EP1346242A1 - Optically active waveguide device comprising a channel on an optical substrate - Google Patents
Optically active waveguide device comprising a channel on an optical substrateInfo
- Publication number
- EP1346242A1 EP1346242A1 EP01990613A EP01990613A EP1346242A1 EP 1346242 A1 EP1346242 A1 EP 1346242A1 EP 01990613 A EP01990613 A EP 01990613A EP 01990613 A EP01990613 A EP 01990613A EP 1346242 A1 EP1346242 A1 EP 1346242A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- substrate
- active layer
- channel
- active
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/011—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour in optical waveguides, not otherwise provided for in this subclass
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/122—Basic optical elements, e.g. light-guiding paths
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/13—Integrated optical circuits characterised by the manufacturing method
- G02B6/134—Integrated optical circuits characterised by the manufacturing method by substitution by dopant atoms
- G02B6/1347—Integrated optical circuits characterised by the manufacturing method by substitution by dopant atoms using ion implantation
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B2006/12035—Materials
- G02B2006/1208—Rare earths
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B2006/12083—Constructional arrangements
- G02B2006/121—Channel; buried or the like
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B2006/12133—Functions
- G02B2006/12142—Modulator
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/30—Optical coupling means for use between fibre and thin-film device
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/011—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour in optical waveguides, not otherwise provided for in this subclass
- G02F1/0113—Glass-based, e.g. silica-based, optical waveguides
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/0147—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on thermo-optic effects
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
- H01S5/204—Strongly index guided structures
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
- H01S5/22—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure
- H01S5/223—Buried stripe structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/50—Amplifier structures not provided for in groups H01S5/02 - H01S5/30
Definitions
- the present invention relates to an optically active device comprising a channel on an optical substrate.
- the field of the invention is that of integrated optics on a substrate, a field to which in particular the active devices which essentially provide an amplification, modulation or switching function of a light signal.
- active devices include an active waveguide and a control element which modulates one of the characteristics of this signal conveyed by the waveguide, this characteristic generally being either the amplitude or the phase.
- a guide comprises a core which is produced on the substrate, this core having a higher refractive index than that of the surrounding medium.
- a first method uses the technology of thin layers.
- the substrate is either silica or silicon on which a thermal oxide has been grown, so that its upper face, the optical substrate, is made of silicon dioxide.
- a layer with an index higher than that of silicon dioxide is deposited on the optical substrate using any known technique such as flame hydrolysis deposition ("Flame Hydrolysis Deposition in English terminology) chemical vapor deposition high or low pressure and assisted or not by plasma, evaporation under vacuum, sputtering or deposition by centrifugation.
- this layer is often silicon dioxide doped with a rare earth such as erbium (signal wavelength 1.55 microns) or neodymium (wavelength signal of 1, 3 microns). If on the other hand it is envisaged to produce a modulator or a switch, the layer is often made of a material having electro-optical properties which is in particular the case of certain polymers. This layer can also have thermo-optical properties, which is for example the case of silicon dioxide.
- a mask defining the heart is then applied to the deposited layer by means of a photolithography technique.
- the core is produced by a chemical etching or dry etching process such as plasma etching, reactive ion etching or ion beam etching.
- the mask is removed after etching and, commonly, a covering layer is deposited on the substrate to bury the heart.
- This covering layer the refractive index of which is lower than that of the core, is intended to limit the disturbances exerted by the surrounding environment, in particular those due to humidity.
- the document GB 2 346 706 teaches a heart produced by means of two layers which are etched successively by means of a single mask. This heart therefore takes the form of two superimposed ribbons having the same dimensions in the plane of the substrate.
- a second method described in document US 4,834,480 uses ion exchange technology.
- the substrate is a glass having a high concentration of mobile ions (Na for example) at relatively low temperature.
- the substrate is again provided with a mask and it is then immersed in a bath containing active ions (K for example).
- the core is thus produced by increasing the refractive index following the exchange of the active ions of the bath with the mobile ions of the substrate.
- the heart is buried by application of an electric field perpendicular to the face of the substrate.
- This method is very simple. However, it requires the selection of a particular substrate which does not necessarily have all the desired characteristics.
- a third method used for the production of passive components implements ion implantation technology.
- the document “Channel waveguides formed in fused silica and silica on silicon by Si, P and Ge ion implantation - LEECH PW et al - IEEE Proceedings: Optoelectronics, Institution of Electrical Engineers, Stevenage GB - Volume 1 3 n ° 5, pages 281 to 286 ” teaches a device deposited on an optical substrate of silicon dioxide. A germanium doped layer is deposited on the substrate, then a mask is applied and the channel is produced by ion implantation of the deposited layer. This layer produces mechanical stresses which cause deformation of the substrate. The deformation, the greater the thicker the layer, is detrimental to the optical specifications of the waveguide and poses difficulties during the photolithography step.
- the present invention thus relates to an optically active device having a suitable spatial resolution and a good surface condition.
- this device comprises a core on an optical substrate and a control element, this core comprising a channel and at least one active layer arranged on the channel, the refractive index of this channel and that of the active layer being greater than that of the substrate; the optical substrate is practically free of mobile ions.
- the geometric definition of the core only depends on that of the channel because the active layer is not etched.
- the device comprises at least one covering layer disposed on the active layer, the index of this covering layer being lower than that of the active layer and that of the channel.
- the channel is integrated into the substrate.
- the channel projects from the substrate.
- the index of the active layer is that of the substrate multiplied by a factor greater than 1.001.
- the thickness of all of the active layers is between 1 and 20 microns.
- the channel results from an ion implantation in the substrate.
- the face of the substrate on which the ion implantation is carried out is made of silicon dioxide.
- the active layer is for example made of silicon dioxide doped with a rare earth, or else in a material which has either electrooptic or thermo-optical properties, this depending on the function of the device.
- the invention also relates to a method of manufacturing an active device on an optical substrate.
- this method comprises the following steps: production of a mask on the optical substrate to define the pattern of a channel,
- the method comprises the following steps:
- the method comprises a step of annealing the substrate which follows the step of ion implantation.
- This method is also adapted to the realization of the various characteristics of the device mentioned above.
- FIG. 1 a sectional diagram of an active waveguide core
- FIG. 2 the manufacture of the heart according to a first variant
- FIG. 3 the manufacture of the heart according to a second variant
- the substrate is made of silicon on which an insulation layer has been produced, either by growth of a thermal oxide, or by deposition of a layer of silicon dioxide SiO 2 or another material such as Si 3 N 4 , AI 2 O 3 , or SiON.
- silicon dioxide SiO 2 or another material such as Si 3 N 4 , AI 2 O 3 , or SiON.
- SiO 2 silicon dioxide
- SiON another material
- These are dielectric materials commonly used in both electronics and optics. opposition to glasses charged with mobile ions. However, it is impossible to guarantee that these materials have a zero concentration of mobile ions. We can only specify that this concentration is very low, less than 0.01% for example.
- the substrate thus has an upper face or optical substrate 11, commonly made of silicon dioxide, with a thickness of 5 to 20 microns, for example.
- the channel 12 produced by ion implantation is here integrated into the optical substrate which is itself covered with an active layer 13.
- the refractive index of the channel is naturally higher than that of silicon dioxide.
- the active layer 5 microns thick for example, is made of erbium-doped silicon dioxide and has a refractive index higher than that of the optical substrate, for example 0.3%. It can possibly result from a stack of thin layers.
- a covering layer 14 which may also consist of a stack of thin layers is provided on the active layer 13. This covering layer, also 5 microns thick, has a lower index than that of the active layer and to that of the canal; in this case it is made of undoped silicon dioxide.
- the substrate does not have an insulation layer so that it merges with the optical substrate.
- It is, for example, a III-V type semiconductor compound, for example InP, GaAs, AIGaAs or InGaAsP.
- the channel is implanted before the deposition of the active layer obtained with a doped material similar to that of the substrate.
- the various materials commonly used in optics such as silica or lithium niobate can be suitable as an optical substrate.
- the core formed by the association of the channel 12 and the active layer 13 can support one or more propagation modes whose properties are a function of the optical and geometric characteristics adopted.
- the extended propagation mode GM extends widely in the active layer 13.
- the width of the channel 7.5 microns for example, and the thickness of this active layer are chosen so that the GM propagation mode is as close as possible to that of optical fibers.
- the effective guide mode index is lower than the refraction of the active layer and that of the channel; it is greater than the refractive index of the upper face 11 and that of the covering layer 14.
- the core can also support a reduced propagation mode PM which extends much less in the active layer 13.
- the channel index should then be relatively high, 1.90 for example.
- the width of the channel can be significantly reduced.
- the effective index of the guided mode is here higher than that of the active layer and lower than that of the channel.
- the lateral confinement of the reduced PM mode is very important.
- the technique of ion implantation was chosen because it makes it possible to precisely define a very thin channel, of the order of a few hundred nanometers.
- the silicon dioxide optical substrate has a refractive index which exhibits little or no variation, it follows that very high accuracy can be obtained on the index of the channel. For example, for an implanted dose of titanium of 10 / cm respectively 10 17 / cm 2 , the precision on the refractive index reaches 10 ⁇ 4 respectively 10 "3. This precision is particularly important when looking for the extended propagation mode GM because the channel index is a parameter which very significantly affects the coupling to the optical fibers.
- a first method of manufacturing the core comprises a first step which consists in carrying out a mask 16 on the optical substrate 15, this by means of a conventional photolithography process
- the mask 16 is made of resin, metal or any other material capable of constituting an impassable barrier for ions during implantation.
- the mask can be obtained by a direct writing process.
- the channel 17 is produced by ion implantation of the masked substrate.
- the implantation dose is between 10 16 / cm 2 and 10 18 / cm 2 and the energy is between a few tens and a few hundred KeV.
- the mask is removed, for example by means of a chemical etching process.
- the substrate is then annealed to reduce losses from propagation within the heart. Annealing notably makes it possible to eliminate the defects of the crystal structure and the absorbent colored centers, to stabilize the new chemical compounds and to restore the canal stoichiometry.
- the temperature is between 400 and 500 ⁇ C
- the atmosphere is controlled or it is open air, while the duration is of the order of a few tens of hours.
- the active layer 18 is then deposited on the substrate 15 by means of any of the known techniques provided that this leads to a low loss material whose refractive index can be easily controlled .
- the covering layer 19 is optionally deposited on the active layer 18.
- this first method has the advantage of defining an active waveguide whose structure is perfectly planar since it does not include an etching step.
- a second method of manufacturing the wave core comprises a first step which consists in implanting the entire optical substrate 20.
- the dose and the implantation energy can be identical to the values mentioned in relation to the first method.
- the next step is to make a mask 21 on the substrate 20.
- This mask has the same pattern as that used during the first method but it must not undergo the implantation step.
- the channel 25 is obtained by etching the optical substrate to a depth at least equal to the implantation depth. Any of the known etching techniques is suitable provided that this leads to acceptable geometrical characteristics of the channel, in particular the profile and the surface condition of its sides.
- the mask is removed and then the substrate is here also subjected to annealing.
- the active layer 22 and possibly the covering layer 23 are then deposited in accordance with the first method.
- an amplifier comprises a first rectilinear channel 31 which, associated with the active layer, constitutes the heart of the active waveguide.
- the control element here takes the form of a second curved channel 32 having a rectilinear coupling section 33 arranged in the immediate vicinity of the first channel 31 and parallel to the latter.
- the second channel 32 is provided for convey an optical pumping signal. It is produced at the same time as the first channel by means of the mask which in fact defines the two channels.
- a modulator consists of an so-called "Mach Zehnder" interferometer.
- the mask now delimits a guide 34 which is subdivided into a first 35 and a second 36 channels, these two channels coming together to reform a single guide.
- a section of the second channel 36 is surrounded by a pair of elongate electrodes 37 whose connections are not shown in the figure.
- These electrodes are for example deposited by means of a thin film technology on the active layer.
- This layer is here made of a material provided with electro-optical properties, that is to say a material whose refractive index is a function of an electric field which is applied to it.
- the control element consists of the combination of the second channel 36 and the pair of electrodes 37.
- a switch consists of a coupler having a first 38 and a second 39 parallel channels which approach in a coupling section to move away again. These two channels made with the same mask are coated with the active layer.
- this layer is made of a material provided with thermooptical properties, ie a material whose refractive index is a function of temperature.
- an electrode 40 is deposited on the active layer, an electrode whose function is the local heating of this layer.
- the electrode 40 constitutes the control element.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Nonlinear Science (AREA)
- Optical Integrated Circuits (AREA)
Abstract
The invention concerns an optically active device comprising an optical waveguide core on an optical substrate (11, 15, 20) and a control element (32-33, 37, 40). The core comprises a channel (12, 17, 25, 35-36, 38-39) and at least an active layer (13, 18, 22) arranged on said channel, the refractive index of the channel and that of the active layer being higher than that of the substrate. The optical substrate (11, 15, 20) has a mobile ion concentration less than 0.01 %. Advantageously, the device further comprises a covering layer (14, 19, 23) arranged on the active layer (13, 18, 22), the index of said covering layer being less than that of the active layer and of the channel. The invention also concerns a method for making said device.
Description
DISPOSITIF A GUIDE D'ONDES OPTIQUES OPTIQUEMENT ACTIF COMPORTANT UN CANAL SUR UN SUBSTRAT OPTIQUEOPTICALLY ACTIVE OPTICAL WAVEGUIDE DEVICE HAVING A CHANNEL ON AN OPTICAL SUBSTRATE
La présente invention concerne un dispositif optiquement actif comportant un canal sur un substrat optique.The present invention relates to an optically active device comprising a channel on an optical substrate.
Le domaine de l'invention est celui de l'optique intégrée sur substrat, domaine auquel appartiennent notamment les dispositifs actifs qui assurent essentiellement une fonction d'amplification, de modulation ou de commutation d'un signal lumineux. De tels dispositifs comportent un guide d'onde actif et un élément de commande qui module une des caractéristiques de ce signal véhiculé par le guide d'onde, cette caractéristique étant généralement soit l'amplitude, soit la phase. Un tel guide comporte un cœur qui est réalisé sur le substrat, ce cœur ayant un indice de réfraction plus élevé que celui du milieu environnant.The field of the invention is that of integrated optics on a substrate, a field to which in particular the active devices which essentially provide an amplification, modulation or switching function of a light signal. Such devices include an active waveguide and a control element which modulates one of the characteristics of this signal conveyed by the waveguide, this characteristic generally being either the amplitude or the phase. Such a guide comprises a core which is produced on the substrate, this core having a higher refractive index than that of the surrounding medium.
Plusieurs méthodes ont été proposées pour fabriquer le cœur du guide d'onde actif. Une première méthode met en oeuvre la technologie des couches minces. Généralement, le substrat est soit en silice soit en silicium sur lequel on a fait croître un oxyde thermique, si bien que sa face supérieure, le substrat optique, est en dioxyde de silicium. Une couche d'indice supérieur à celui du dioxyde de silicium est déposée sur le substrat optique au moyen d'une quelconque technique connue telle que dépôt par hydrolyse à la flamme ("Flame Hydrolysis Déposition en terminologie anglo-saxonne) dépôt chimique en phase vapeur haute ou basse pression et assisté ou non par plasma, évaporation sous vide, pulvérisation cathodique ou dépôt par centrifugation.Several methods have been proposed for manufacturing the core of the active waveguide. A first method uses the technology of thin layers. Generally, the substrate is either silica or silicon on which a thermal oxide has been grown, so that its upper face, the optical substrate, is made of silicon dioxide. A layer with an index higher than that of silicon dioxide is deposited on the optical substrate using any known technique such as flame hydrolysis deposition ("Flame Hydrolysis Deposition in English terminology) chemical vapor deposition high or low pressure and assisted or not by plasma, evaporation under vacuum, sputtering or deposition by centrifugation.
Lorsqu'il s'agit de réaliser un amplificateur, cette couche est souvent du dioxyde de silicium dopé avec une terre rare telle que l'erbium (longueur d'onde du signal de 1,55 microns) ou le néodyme (longueur d'onde du signal de 1 ,3 microns). Si par contre il est envisagé de produire un modulateur ou un commutateur, la couche est souvent constituée d'un matériau présentant des propriétés électro-optiques ce qui est notamment le cas de certains polymères. Cette couche peut également présenter des propriétés thermo-optiques, ce qui est par exemple le cas du dioxyde de silicium.When it comes to making an amplifier, this layer is often silicon dioxide doped with a rare earth such as erbium (signal wavelength 1.55 microns) or neodymium (wavelength signal of 1, 3 microns). If on the other hand it is envisaged to produce a modulator or a switch, the layer is often made of a material having electro-optical properties which is in particular the case of certain polymers. This layer can also have thermo-optical properties, which is for example the case of silicon dioxide.
Un masque définissant le cœur est alors appliqué sur la couche déposée au moyen d'une technique de photolithographie. Ensuite, le cœur est réalisé par un procédé de gravure chimique ou de gravure sèche tel que gravure plasma, gravure ionique réactive ou gravure par faisceau d'ions. Le masque est retiré après la gravure et, couramment, une couche de recouvrement est
déposée sur le substrat pour enterrer le cœur. Cette couche de recouvrement dont l'indice de réfraction est inférieur à celui du cœur est prévue pour limiter les perturbations exercées par le milieu environnant, notamment celles dues à l'humidité. Ainsi, le document GB 2 346 706 enseigne un cœur réalisé au moyen de deux couches qui sont gravées successivement au moyen d'un seul masque. Ce cœur prend donc la forme de deux rubans superposés présentant les mêmes dimensions dans le plan du substrat.A mask defining the heart is then applied to the deposited layer by means of a photolithography technique. Then, the core is produced by a chemical etching or dry etching process such as plasma etching, reactive ion etching or ion beam etching. The mask is removed after etching and, commonly, a covering layer is deposited on the substrate to bury the heart. This covering layer, the refractive index of which is lower than that of the core, is intended to limit the disturbances exerted by the surrounding environment, in particular those due to humidity. Thus, the document GB 2 346 706 teaches a heart produced by means of two layers which are etched successively by means of a single mask. This heart therefore takes the form of two superimposed ribbons having the same dimensions in the plane of the substrate.
Cette méthode requiert une opération de gravure qu'il est difficile de maîtriser tant sur le plan de la résolution spatiale que sur l'état de surface des flancs du cœur. Ainsi, la gravure du dioxyde de silicium dopé à l'erbium au moyen d'un gaz réactif fluoré tel que le CHF3 produit du fluorure d'erbium, composé qui augmente sensiblement la rugosité de la surface gravée. Or l'état de surface et la géométrie du cœur conditionnent directement les pertes à la propagation du guide d'onde actif.This method requires an engraving operation which is difficult to master both in terms of spatial resolution and in terms of the surface condition of the sides of the heart. Thus, the etching of silicon dioxide doped with erbium by means of a fluorinated reactive gas such as CHF 3 produces erbium fluoride, a compound which appreciably increases the roughness of the etched surface. However, the surface condition and the geometry of the core directly condition the losses on propagation of the active waveguide.
Une deuxième méthode décrite dans le document US 4 834 480 met en oeuvre la technologie d'échange d'ions. Dans ce cas, le substrat est un verre présentant une forte concentration d'ions mobiles (Na par exemple) à température relativement basse. Le substrat est là aussi pourvu d'un masque et il est ensuite immergé dans un bain contenant des ions actifs (K par exemple). Le cœur est ainsi réalisé par augmentation de l'indice de réfraction consécutive à l'échange des ions actifs du bain avec les ions mobiles du substrat. Puis, généralement, le cœur est enterré par application d'un champ électrique perpendiculaire à la face du substrat. Cette méthode présente une grande simplicité. Cependant, elle impose la sélection d'un substrat particulier qui n'a pas nécessairement toutes les caractéristiques souhaitées. Il n'est par exemple pas possible de réaliser un échange d'ions à partir du silicium alors que ce matériau offre de nombreux avantages tant au niveau du coût, des procédés de traitement qui sont ceux utilisés en microélectronique, de ses propriétés thermiques que de sa caractérisation. De plus, l'échange d'ions provoque une diffusion latérale importante des ions actifs, si bien que la résolution spatiale est ici aussi sérieusement limitée.A second method described in document US 4,834,480 uses ion exchange technology. In this case, the substrate is a glass having a high concentration of mobile ions (Na for example) at relatively low temperature. The substrate is again provided with a mask and it is then immersed in a bath containing active ions (K for example). The core is thus produced by increasing the refractive index following the exchange of the active ions of the bath with the mobile ions of the substrate. Then, generally, the heart is buried by application of an electric field perpendicular to the face of the substrate. This method is very simple. However, it requires the selection of a particular substrate which does not necessarily have all the desired characteristics. It is for example not possible to carry out an ion exchange from silicon while this material offers many advantages both in terms of cost, treatment methods which are those used in microelectronics, its thermal properties and its characterization. In addition, the ion exchange causes significant lateral diffusion of the active ions, so that the spatial resolution here is also seriously limited.
Une troisième méthode employée pour la réalisation de composants passifs met en œuvre la technologie d'implantation ionique. Le document « Channel waveguides formed in fused silica and silica on silicon by Si, P and
Ge ion implantation - LEECH P W et al - IEEE Proceedings : Optoelectronics, Institution of Electrical Engineers, Stevenage GB - Volume 1 3 n° 5, pages 281 à 286 » enseigne un dispositif déposé sur un substrat optique en dioxyde de silicium. Une couche dopée au germanium est déposée sur le substrat puis un masque est appliqué et le canal est réalisé par implantation ionique de la couche déposée. Cette couche produit des contraintes mécaniques qui entraînent une déformation du substrat. La déformation, d'autant plus importante que la couche est épaisse, est préjudiciable aux spécifications optiques du guide d'onde et pose des difficultés lors de l'étape de photolithographie. La présente invention a ainsi pour objet un dispositif optiquement actif présentant une résolution spatiale convenable et un bon état de surface.A third method used for the production of passive components implements ion implantation technology. The document “Channel waveguides formed in fused silica and silica on silicon by Si, P and Ge ion implantation - LEECH PW et al - IEEE Proceedings: Optoelectronics, Institution of Electrical Engineers, Stevenage GB - Volume 1 3 n ° 5, pages 281 to 286 ”teaches a device deposited on an optical substrate of silicon dioxide. A germanium doped layer is deposited on the substrate, then a mask is applied and the channel is produced by ion implantation of the deposited layer. This layer produces mechanical stresses which cause deformation of the substrate. The deformation, the greater the thicker the layer, is detrimental to the optical specifications of the waveguide and poses difficulties during the photolithography step. The present invention thus relates to an optically active device having a suitable spatial resolution and a good surface condition.
Selon l'invention, ce dispositif comporte un cœur sur un substrat optique et un élément de commande, ce cœur comprenant un canal et au moins une couche active agencée sur le canal, l'indice de réfraction de ce canal et celui de la couche active étant supérieurs à celui du substrat ; le substrat optique est pratiquement exempt d'ions mobiles.According to the invention, this device comprises a core on an optical substrate and a control element, this core comprising a channel and at least one active layer arranged on the channel, the refractive index of this channel and that of the active layer being greater than that of the substrate; the optical substrate is practically free of mobile ions.
Sur un substrat approprié, la définition géométrique du cœur dépend seulement de celle du canal car la couche active n'est pas gravée.On a suitable substrate, the geometric definition of the core only depends on that of the channel because the active layer is not etched.
De préférence, le dispositif comporte au moins une couche de recouvrement disposée sur la couche active, l'indice de cette couche de recouvrement étant inférieur à celui de la couche active et à celui du canal.Preferably, the device comprises at least one covering layer disposed on the active layer, the index of this covering layer being lower than that of the active layer and that of the channel.
Suivant un premier mode de réalisation, le canal est intégré dans le substrat.According to a first embodiment, the channel is integrated into the substrate.
Suivant un deuxième mode de réalisation, le canal fait saillie sur le substrat.According to a second embodiment, the channel projects from the substrate.
Avantageusement, l'indice de la couche active vaut celui du substrat multiplié par un facteur supérieur à 1,001.Advantageously, the index of the active layer is that of the substrate multiplied by a factor greater than 1.001.
A titre d'exemple, l'épaisseur de l'ensemble des couches actives est comprise entre 1 et 20 microns. Selon une caractéristique privilégiée, le canal résulte d'une implantation ionique dans le substrat.For example, the thickness of all of the active layers is between 1 and 20 microns. According to a privileged characteristic, the channel results from an ion implantation in the substrate.
Par ailleurs, il est conseillé que la face du substrat sur laquelle est réalisée l'implantation ionique soit en dioxyde de silicium.In addition, it is recommended that the face of the substrate on which the ion implantation is carried out is made of silicon dioxide.
La couche active est par exemple en dioxyde de silicium dopé avec une terre rare, ou bien dans un matériau qui présente des propriétés soit électrooptiques, soit thermo-optiques, ceci selon la fonction du dispositif.
L'invention vise également une méthode de fabrication d'un dispositif actif sur un substrat optique.The active layer is for example made of silicon dioxide doped with a rare earth, or else in a material which has either electrooptic or thermo-optical properties, this depending on the function of the device. The invention also relates to a method of manufacturing an active device on an optical substrate.
Selon une première variante, cette méthode comprend les étapes suivantes : - réalisation d'un masque sur le substrat optique pour définir le motif d'un canal,According to a first variant, this method comprises the following steps: production of a mask on the optical substrate to define the pattern of a channel,
- implantation ionique du substrat masqué,- ion implantation of the masked substrate,
- retrait du masque,- removal of the mask,
- dépôt d'au moins une couche active sur le substrat, l'indice de réfraction de cette couche active étant supérieur à celui du substrat. Selon une deuxième variante, la méthode comprend les étapes suivantes :depositing at least one active layer on the substrate, the refractive index of this active layer being greater than that of the substrate. According to a second variant, the method comprises the following steps:
- implantation ionique du substrat,- ion implantation of the substrate,
- réalisation d'un masque sur le substrat pour définir le motif d'un canal,- production of a mask on the substrate to define the pattern of a channel,
- gravure du substrat sur une profondeur au moins égale à la profondeur d'implantation,- etching of the substrate to a depth at least equal to the implantation depth,
- retrait du masque,- removal of the mask,
- dépôt d'au moins une couche active sur le substrat, l'indice de réfraction de cette couche active étant supérieur à celui du substrat.depositing at least one active layer on the substrate, the refractive index of this active layer being greater than that of the substrate.
Avantageusement, la méthode comprend une étape de recuit du substrat qui fait suite à l'étape d'implantation ionique.Advantageously, the method comprises a step of annealing the substrate which follows the step of ion implantation.
Cette méthode est d'autre part adaptée à la réalisation des différentes caractéristiques du dispositif mentionnées ci-dessus.This method is also adapted to the realization of the various characteristics of the device mentioned above.
La présente invention apparaîtra maintenant avec plus de détails dans le cadre de la description qui suit d'exemples de réalisation donnés à titre illustratif en se référant aux figures annexées qui représentent :The present invention will now appear in more detail in the context of the following description of exemplary embodiments given by way of illustration with reference to the appended figures which represent:
- la figure 1 , un schéma en coupe d'un cœur de guide d'onde actif,FIG. 1, a sectional diagram of an active waveguide core,
- la figure 2, la fabrication du cœur selon une première variante,FIG. 2, the manufacture of the heart according to a first variant,
- la figure 3, la fabrication du cœur selon une deuxième variante, etFIG. 3, the manufacture of the heart according to a second variant, and
- la figure 4, un ensemble de dispositifs actifs vus de dessus. Dans un premier temps, afin de simplifier la présentation de l'invention, seule la réalisation du cœur du guide d'onde actif sera exposée.- Figure 4, a set of active devices seen from above. Initially, in order to simplify the presentation of the invention, only the production of the core of the active waveguide will be exposed.
En référence à la figure 1a, selon une première variante, le substrat est en silicium sur lequel une couche d'isolation a été réalisée, soit par croissance d'un oxyde thermique, soit par dépôt d'une couche de dioxyde de silicium SiO2 ou d'un autre matériau tel que Si3N4, AI2O3, ou SiON. Il s'agit là de matériaux diélectriques couramment utilisés tant en électronique qu'en optique par
opposition aux verres chargés en ions mobiles. Il est toutefois impossible de garantir que ces matériaux présentent une concentration nulle en ions mobiles. On peut seulement préciser que cette concentration est très faible, inférieure à 0,01% par exemple. Le substrat présente ainsi une face supérieure ou substrat optique 11 , couramment en dioxyde de silicium, d'une épaisseur de 5 à 20 microns, par exemple. Le canal 12 réalisé par implantation ionique est ici intégré dans le substrat optique qui est lui-même recouvert d'une couche active 13. L'indice de réfraction du canal est naturellement plus élevé que celui du dioxyde de silicium. La couche active de 5 microns d'épaisseur, par exemple, est en dioxyde de silicium dopé à l'erbium et présente un indice de réfraction supérieur à celui du substrat optique, de 0,3% par exemple. Elle peut éventuellement résulter d'un empilement de couches minces. De préférence, une couche de recouvrement 14 qui peut également consister en un empilement de couches minces est prévue sur la couche active 13. Cette couche de recouvrement, de 5 microns d'épaisseur également, a un indice inférieur à celui de la couche active et à celui du canal ; dans le cas présent elle est en dioxyde de silicium non dopé.With reference to FIG. 1a, according to a first variant, the substrate is made of silicon on which an insulation layer has been produced, either by growth of a thermal oxide, or by deposition of a layer of silicon dioxide SiO 2 or another material such as Si 3 N 4 , AI 2 O 3 , or SiON. These are dielectric materials commonly used in both electronics and optics. opposition to glasses charged with mobile ions. However, it is impossible to guarantee that these materials have a zero concentration of mobile ions. We can only specify that this concentration is very low, less than 0.01% for example. The substrate thus has an upper face or optical substrate 11, commonly made of silicon dioxide, with a thickness of 5 to 20 microns, for example. The channel 12 produced by ion implantation is here integrated into the optical substrate which is itself covered with an active layer 13. The refractive index of the channel is naturally higher than that of silicon dioxide. The active layer 5 microns thick, for example, is made of erbium-doped silicon dioxide and has a refractive index higher than that of the optical substrate, for example 0.3%. It can possibly result from a stack of thin layers. Preferably, a covering layer 14 which may also consist of a stack of thin layers is provided on the active layer 13. This covering layer, also 5 microns thick, has a lower index than that of the active layer and to that of the canal; in this case it is made of undoped silicon dioxide.
Selon une deuxième variante, le substrat ne présente pas de couche d'isolation si bien qu'il se confond avec le substrat optique. Il s'agit par exemple d'un composé semi-conducteur de type lll-V, par exemple InP, GaAs, AIGaAs ou InGaAsP. Le canal est implanté avant le dépôt de la couche active obtenue avec un matériau dopé similaire à celui du substrat. Naturellement, les différents matériaux couramment employés en optique tels que la silice ou le niobate de lithium peuvent convenir en tant que substrat optique. Quelle que soit la variante adoptée, le cœur formé par l'association du canal 12 et de la couche active 13 peut supporter un ou plusieurs modes de propagation dont les propriétés sont fonction des caractéristiques optiques et géométriques adoptées.According to a second variant, the substrate does not have an insulation layer so that it merges with the optical substrate. It is, for example, a III-V type semiconductor compound, for example InP, GaAs, AIGaAs or InGaAsP. The channel is implanted before the deposition of the active layer obtained with a doped material similar to that of the substrate. Naturally, the various materials commonly used in optics such as silica or lithium niobate can be suitable as an optical substrate. Whatever the variant adopted, the core formed by the association of the channel 12 and the active layer 13 can support one or more propagation modes whose properties are a function of the optical and geometric characteristics adopted.
En référence à la figure 1 b, lorsque l'indice de réfraction du canal est relativement faible, 1,56 par exemple, le mode de propagation étendu GM s'étend largement dans la couche active 13. La largeur du canal, 7,5 microns par exemple, et l'épaisseur de cette couche active sont choisies de sorte que le mode de propagation GM soit aussi voisin que possible de celui des fibres optiques. On peut alors obtenir un coefficient de couplage aux fibres d'une valeur de 90%. L'indice effectif du mode guidé est inférieur à l'indice de
réfraction de la couche active et à celui du canal ; il est supérieur à l'indice de réfraction de la face supérieure 11 et à celui de la couche de recouvrement 14. En référence à la figure 1c, il faut noter que le cœur peut également supporter un mode de propagation réduit PM qui s'étend beaucoup moins dans la couche active 13. Il convient alors que l'indice du canal soit relativement élevé, 1,90 par exemple. La largeur du canal peut être sensiblement réduite.With reference to FIG. 1 b, when the refractive index of the channel is relatively low, 1.56 for example, the extended propagation mode GM extends widely in the active layer 13. The width of the channel, 7.5 microns for example, and the thickness of this active layer are chosen so that the GM propagation mode is as close as possible to that of optical fibers. We can then obtain a fiber coupling coefficient of a value of 90%. The effective guide mode index is lower than the refraction of the active layer and that of the channel; it is greater than the refractive index of the upper face 11 and that of the covering layer 14. With reference to FIG. 1c, it should be noted that the core can also support a reduced propagation mode PM which extends much less in the active layer 13. The channel index should then be relatively high, 1.90 for example. The width of the channel can be significantly reduced.
L'indice effectif du mode guidé est ici supérieur à celui de la couche active et inférieur à celui du canal. Le confinement latéral du mode réduit PM est très important. La technique de l'implantation ionique a été retenue car elle permet de définir précisément un canal de très faible épaisseur, de l'ordre de quelques centaines de nanomètres.The effective index of the guided mode is here higher than that of the active layer and lower than that of the channel. The lateral confinement of the reduced PM mode is very important. The technique of ion implantation was chosen because it makes it possible to precisely define a very thin channel, of the order of a few hundred nanometers.
Par ailleurs, cette technique bénéficie maintenant d'une très grande précision sur les doses d'ions implantés, typiquement 1%. Le substrat optique en dioxyde de silicium a un indice de réfraction qui ne présente pas ou peu de variations, il s'ensuit que l'on peut obtenir une très grande précision sur l'indice du canal. A titre d'exemple, pour une dose implantée de titane de 10 /cm respectivement 1017/cm2, la précision sur l'indice de réfraction atteint 10~4 respectivement 10"3. Cette précision est particulièrement importante lorsque l'on recherche le mode de propagation étendu GM car l'indice du canal est un paramètre qui affecte de manière très sensible le couplage aux fibres optiques. En référence à la figure 2a, une première méthode de fabrication du cœur comporte une première étape qui consiste à réaliser un masque 16 sur le substrat optique 15, ceci au moyen d'un procédé classique de photolithographie. Le masque 16 est en résine, en métal ou en tout autre matériau susceptible de constituer une barrière infranchissable pour les ions lors de l'implantation.Furthermore, this technique now benefits from very high precision on the doses of implanted ions, typically 1%. The silicon dioxide optical substrate has a refractive index which exhibits little or no variation, it follows that very high accuracy can be obtained on the index of the channel. For example, for an implanted dose of titanium of 10 / cm respectively 10 17 / cm 2 , the precision on the refractive index reaches 10 ~ 4 respectively 10 "3. This precision is particularly important when looking for the extended propagation mode GM because the channel index is a parameter which very significantly affects the coupling to the optical fibers. With reference to FIG. 2a, a first method of manufacturing the core comprises a first step which consists in carrying out a mask 16 on the optical substrate 15, this by means of a conventional photolithography process The mask 16 is made of resin, metal or any other material capable of constituting an impassable barrier for ions during implantation.
Eventuellement, le masque peut être obtenu par un procédé d'écriture directe.Optionally, the mask can be obtained by a direct writing process.
En référence à la figure 2b, le canal 17 est produit par implantation ionique du substrat masqué. A titre d'exemple, pour une implantation de titane, la dose d'implantation est comprise entre 1016/cm2 et 1018/cm2 et l'énergie est comprise entre quelques dizaines et quelques centaines de KeV.With reference to FIG. 2b, the channel 17 is produced by ion implantation of the masked substrate. For example, for a titanium implantation, the implantation dose is between 10 16 / cm 2 and 10 18 / cm 2 and the energy is between a few tens and a few hundred KeV.
En référence à la figure 2c, le masque est retiré, par exemple au moyen d'un procédé de gravure chimique. Le substrat est ensuite soumis à un recuit pour réduire les pertes à la propagation au sein du cœur. Le recuit permet notamment d'éliminer les défauts de la structure cristalline et les centres colorés absorbants, de stabiliser les nouveaux composés chimiques et de restituer la
stœchiométrie du canal. A titre d'exemple, la température est comprise entre 400 et 500βC, l'atmosphère est contrôlée ou bien il s'agit de l'air libre, tandis que la durée est de l'ordre de quelques dizaines d'heures.Referring to Figure 2c, the mask is removed, for example by means of a chemical etching process. The substrate is then annealed to reduce losses from propagation within the heart. Annealing notably makes it possible to eliminate the defects of the crystal structure and the absorbent colored centers, to stabilize the new chemical compounds and to restore the canal stoichiometry. For example, the temperature is between 400 and 500 β C, the atmosphere is controlled or it is open air, while the duration is of the order of a few tens of hours.
En référence à la figure 2d, la couche active 18 est alors déposée sur le substrat 15 au moyen de l'une quelconque des techniques connues pourvu que celle-ci conduise à un matériau à faibles pertes dont l'indice de réfraction peut être aisément contrôlé. Enfin, la couche de recouvrement 19 est éventuellement déposée sur la couche active 18.With reference to FIG. 2d, the active layer 18 is then deposited on the substrate 15 by means of any of the known techniques provided that this leads to a low loss material whose refractive index can be easily controlled . Finally, the covering layer 19 is optionally deposited on the active layer 18.
On remarque que cette première méthode présente l'avantage de définir un guide d'onde actif dont la structure est parfaitement plane puisqu'elle ne comprend pas d'étape de gravure.Note that this first method has the advantage of defining an active waveguide whose structure is perfectly planar since it does not include an etching step.
En référence à la figure 3a, une deuxième méthode de fabrication du cœur d'onde comporte une première étape qui consiste à implanter la totalité du substrat optique 20. La dose et l'énergie d'implantation peuvent être identiques aux valeurs mentionnées en rapport avec la première méthode.With reference to FIG. 3a, a second method of manufacturing the wave core comprises a first step which consists in implanting the entire optical substrate 20. The dose and the implantation energy can be identical to the values mentioned in relation to the first method.
En référencera la figure 3b, l'étape suivante consiste à réaliser un masque 21 sur le substrat 20. Ce masque a le même motif que celui employé au cours de la première méthode mais il ne doit pas subir l'étape d'implantation.Referring to Figure 3b, the next step is to make a mask 21 on the substrate 20. This mask has the same pattern as that used during the first method but it must not undergo the implantation step.
En référence à la figure 3c, le canal 25 est obtenu par gravure du substrat optique sur une profondeur au moins égale à la profondeur d'implantation. L'une quelconque des techniques connues de gravure convient pourvu que celle-ci conduise à des caractéristiques géométriques acceptables du canal, notamment le profil et l'état de surface de ses flancs.Referring to Figure 3c, the channel 25 is obtained by etching the optical substrate to a depth at least equal to the implantation depth. Any of the known etching techniques is suitable provided that this leads to acceptable geometrical characteristics of the channel, in particular the profile and the surface condition of its sides.
En référence à la figure 3d, le masque est retiré puis le substrat est ici aussi soumis à un recuit. La couche active 22 et éventuellement la couche de recouvrement 23 sont alors déposées conformément à la première méthode.With reference to FIG. 3d, the mask is removed and then the substrate is here also subjected to annealing. The active layer 22 and possibly the covering layer 23 are then deposited in accordance with the first method.
Selon cette deuxième méthode, les inconvénients liés à la gravure sont considérablement limités car le canal présente une faible épaisseur.According to this second method, the drawbacks associated with etching are considerably limited because the channel has a small thickness.
Il convient maintenant d'exposer comment l'invention permet de réaliser des dispositifs optiquement actifs.It is now necessary to explain how the invention makes it possible to produce optically active devices.
En référence à la figure 4a, un amplificateur comporte un premier canal rectiligne 31 qui, associé à la couche active, constitue le cœur du guide d'onde actif. L'élément de commande prend ici la forme d'un deuxième canal 32 incurvé présentant une section de couplage 33 rectiligne disposée à proximité immédiate du premier canal 31 et parallèle à celui-ci. Le second canal 32 est prévu pour
véhiculer un signal de pompage optique. Il est réalisé en même temps que le premier canal au moyen du masque qui définit de fait les deux canaux.With reference to FIG. 4a, an amplifier comprises a first rectilinear channel 31 which, associated with the active layer, constitutes the heart of the active waveguide. The control element here takes the form of a second curved channel 32 having a rectilinear coupling section 33 arranged in the immediate vicinity of the first channel 31 and parallel to the latter. The second channel 32 is provided for convey an optical pumping signal. It is produced at the same time as the first channel by means of the mask which in fact defines the two channels.
En référence à la figure 4b, un modulateur consiste en un interféromètre dit de "Mach Zehnder". Le masque délimite maintenant un guide 34 qui se subdivise en un premier 35 et un second 36 canaux, ces deux canaux se rejoignant pour reformer un guide unique. Une section du second canal 36 est ceinte d'une paire d'électrodes 37 longilignes dont les connexions ne sont pas représentées dans la figure. Ces électrodes sont par exemple déposées au moyen d'une technologie couches minces sur la couche active. Cette couche est ici en un matériau pourvu de propriétés électro-optiques, c'est à dire un matériau dont l'indice de réfraction est fonction d'un champ électrique qui lui est appliqué. L'élément de commande consiste dans la combinaison du second canal 36 et de la paire d'électrodes 37.With reference to FIG. 4b, a modulator consists of an so-called "Mach Zehnder" interferometer. The mask now delimits a guide 34 which is subdivided into a first 35 and a second 36 channels, these two channels coming together to reform a single guide. A section of the second channel 36 is surrounded by a pair of elongate electrodes 37 whose connections are not shown in the figure. These electrodes are for example deposited by means of a thin film technology on the active layer. This layer is here made of a material provided with electro-optical properties, that is to say a material whose refractive index is a function of an electric field which is applied to it. The control element consists of the combination of the second channel 36 and the pair of electrodes 37.
En référence à la figure 4c, un commutateur consiste en un coupleur comportant un premier 38 et un second 39 canaux parallèles qui se rapprochent dans une section de couplage pour s'éloigner à nouveau. Ces deux canaux réalisés avec un même masque sont revêtus de la couche active. A titre d'exemple, cette couche est en un matériau pourvu de propriétés thermooptiques, c'est à dire un matériau dont l'indice de réfraction est fonction de la température. Au niveau de la section de couplage, au dessus du second canal 39, une électrode 40 est déposée sur la couche active, électrode dont la fonction est le chauffage local de cette couche. L'électrode 40 constitue l'élément de commande.Referring to Figure 4c, a switch consists of a coupler having a first 38 and a second 39 parallel channels which approach in a coupling section to move away again. These two channels made with the same mask are coated with the active layer. By way of example, this layer is made of a material provided with thermooptical properties, ie a material whose refractive index is a function of temperature. At the coupling section, above the second channel 39, an electrode 40 is deposited on the active layer, an electrode whose function is the local heating of this layer. The electrode 40 constitutes the control element.
Les exemples de réalisation de l'invention présentés ci-dessus ont été choisis pour leur caractère concret. Il ne serait cependant pas possible de répertorier de manière exhaustive tous les modes de réalisation que recouvre cette invention. En particulier, toute étape ou tout moyen décrit peut-être remplacé par une étape ou un moyen équivalent sans sortir du cadre de la présente invention.
The embodiments of the invention presented above have been chosen for their specific nature. However, it would not be possible to exhaustively list all the embodiments covered by this invention. In particular, any step or any means described may be replaced by a step or equivalent means without departing from the scope of the present invention.
Claims
REVENDICATIONS
1 ) Dispositif optiquement actif comportant un cœur sur un substrat optique1) Optically active device comprising a core on an optical substrate
(11 , 15, 20) et un élément de commande (32-33, 37, 40), ce cœur comprenant un canal (12, 17, 25, 31 , 35-36, 38-39) et au moins une couche active (13, 18, 22) agencée sur ledit canal, l'indice de réfraction de ce canal et celui de la couche active étant supérieurs à celui du substrat, caractérisé en ce que ledit substrat optique (11 , 15, 20) présente une concentration en ions mobiles inférieure à 0,01%.(11, 15, 20) and a control element (32-33, 37, 40), this core comprising a channel (12, 17, 25, 31, 35-36, 38-39) and at least one active layer (13, 18, 22) arranged on said channel, the refractive index of this channel and that of the active layer being greater than that of the substrate, characterized in that said optical substrate (11, 15, 20) has a concentration in mobile ions less than 0.01%.
2) Dispositif selon la revendication 1 , caractérisé en ce qu'il comporte au moins une couche de recouvrement (14, 19, 23) disposée sur ladite couche active (13, 18, 22), l'indice de cette couche de recouvrement étant inférieur à celui de la couche active et à celui du canal (12, 17, 25, 31 , 35-36, 38-39).2) Device according to claim 1, characterized in that it comprises at least one covering layer (14, 19, 23) disposed on said active layer (13, 18, 22), the index of this covering layer being lower than that of the active layer and that of the channel (12, 17, 25, 31, 35-36, 38-39).
3) Dispositif selon l'une quelconque des revendications 1 ou 2, caractérisé en ce que ledit canal (12, 17) est intégré dans ledit substrat (11 , 15). 4) Dispositif selon l'une quelconque des revendications 1 ou 2, caractérisé en ce que ledit canal (25) fait saillie sur ledit substrat (20). 5) Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que l'indice de ladite couche active (13, 18, 22) vaut celui du substrat (11 , 15, 20) multiplié par un facteur supérieur à 1 ,001. 6) Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que l'épaisseur de l'ensemble des couches actives (13, 18, 22) est comprise entre 1 et 20 microns.3) Device according to any one of claims 1 or 2, characterized in that said channel (12, 17) is integrated in said substrate (11, 15). 4) Device according to any one of claims 1 or 2, characterized in that said channel (25) projects from said substrate (20). 5) Device according to any one of the preceding claims, characterized in that the index of said active layer (13, 18, 22) is equal to that of the substrate (11, 15, 20) multiplied by a factor greater than 1, 001 . 6) Device according to any one of the preceding claims, characterized in that the thickness of all the active layers (13, 18, 22) is between 1 and 20 microns.
7) Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que ledit canal (12, 17, 25, 31 , 35-36, 38-39) résulte d'une implantation ionique dans ledit substrat (11, 15, 20).7) Device according to any one of the preceding claims, characterized in that said channel (12, 17, 25, 31, 35-36, 38-39) results from an ion implantation in said substrate (11, 15, 20 ).
8) Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que la face du substrat (11 , 15, 20) sur laquelle est réalisée l'implantation ionique est en dioxyde de silicium.8) Device according to any one of the preceding claims, characterized in that the face of the substrate (11, 15, 20) on which the ion implantation is carried out is made of silicon dioxide.
9) Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que ladite couche active (13, 18, 22) est en dioxyde de silicium dopé avec une terre rare.9) Device according to any one of the preceding claims, characterized in that said active layer (13, 18, 22) is made of silicon dioxide doped with a rare earth.
10) Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que ladite couche active (13, 18, 22) présente des propriétés électro-optiques.
11) Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que ladite couche active (13, 18, 22) présente des propriétés thermo-optiques.10) Device according to any one of the preceding claims, characterized in that said active layer (13, 18, 22) has electro-optical properties. 11) Device according to any one of the preceding claims, characterized in that said active layer (13, 18, 22) has thermo-optical properties.
12) Méthode de fabrication d'un dispositif actif sur un substrat optique comprenant une étape de réalisation d'au moins un élément de commande (32-12) Method for manufacturing an active device on an optical substrate comprising a step of producing at least one control element (32-
33, 37, 40), caractérisée en ce qu'elle comprend de plus les étapes suivantes :33, 37, 40), characterized in that it further comprises the following steps:
- réalisation d'un masque (16) sur ledit substrat (15) pour définir le motif d'un canal (17),- production of a mask (16) on said substrate (15) to define the pattern of a channel (17),
- implantation ionique du substrat masqué, - retrait dudit masque,- ion implantation of the masked substrate, - removal of said mask,
- dépôt d'au moins une couche active (18) sur le substrat, l'indice de réfraction de cette couche active étant supérieur à celui du substrat.- Deposition of at least one active layer (18) on the substrate, the refractive index of this active layer being greater than that of the substrate.
13) Méthode de fabrication d'un dispositif actif sur un substrat optique comprenant une étape de réalisation d'au moins un élément de commande (32- 33, 37, 40), caractérisée en ce qu'elle comprend de plus les étapes suivantes :13) Method for manufacturing an active device on an optical substrate comprising a step of producing at least one control element (32- 33, 37, 40), characterized in that it further comprises the following steps:
- implantation ionique du substrat (20),- ion implantation of the substrate (20),
- réalisation d'un masque (21 ) sur ledit substrat pour définir le motif d'un canal (25),- production of a mask (21) on said substrate to define the pattern of a channel (25),
- gravure du substrat sur une profondeur au moins égale à la profondeur d'implantation,- etching of the substrate to a depth at least equal to the implantation depth,
- retrait dudit masque,- removal of said mask,
- dépôt d'au moins une couche active (22) sur le substrat, l'indice de réfraction de cette couche active étant supérieur à celui du substrat.- Deposition of at least one active layer (22) on the substrate, the refractive index of this active layer being greater than that of the substrate.
14) Méthode selon l'une quelconque des revendications 12 ou 13, caractérisée en ce qu'elle comprend une étape de recuit du substrat (15, 20) qui fait suite à l'étape d'implantation ionique.14) Method according to any one of claims 12 or 13, characterized in that it comprises a step of annealing the substrate (15, 20) which follows the step of ion implantation.
15) Méthode selon l'une quelconque des revendications 12 ou 13, caractérisée en ce qu'elle comprend une étape de dépôt d'une couche de recouvrement (19, 23) sur ladite couche active (18, 22), l'indice de cette couche de recouvrement étant inférieur à celui de la couche active et à celui du canal (17, 25).15) Method according to any one of claims 12 or 13, characterized in that it comprises a step of depositing a covering layer (19, 23) on said active layer (18, 22), the index of this covering layer being lower than that of the active layer and that of the channel (17, 25).
16) Méthode selon l'une quelconque des revendications 12 ou 13, caractérisée en ce que l'indice de ladite couche active (18, 22) vaut celui du substrat (15, 20) multiplié par un facteur supérieur à 1 ,001.
17) Méthode selon l'une quelconque des revendications 12 ou 13, caractérisée en ce que l'épaisseur de l'ensemble des couches actives (18, 22) est comprise entre 1 et 20 microns.16) Method according to any one of claims 12 or 13, characterized in that the index of said active layer (18, 22) is that of the substrate (15, 20) multiplied by a factor greater than 1, 001. 17) Method according to any one of claims 12 or 13, characterized in that the thickness of all the active layers (18, 22) is between 1 and 20 microns.
18) Méthode selon l'une quelconque des revendications 12 ou 13, caractérisée en ce que la face (15, 20) du substrat sur laquelle est réalisée l'implantation ionique est en dioxyde de silicium.18) Method according to any one of claims 12 or 13, characterized in that the face (15, 20) of the substrate on which the ion implantation is carried out is made of silicon dioxide.
19) Méthode selon l'une quelconque des revendications 12 ou 13, caractérisée en ce que le matériau de ladite couche active (18, 22) est du dioxyde de silicium dopé avec une terre rare. 20) Méthode selon l'une quelconque des revendications 12 ou 13, caractérisée en ce que le matériau de ladite couche active (18, 22) présente des propriétés électro-optiques.19) Method according to any one of claims 12 or 13, characterized in that the material of said active layer (18, 22) is silicon dioxide doped with a rare earth. 20) Method according to any one of claims 12 or 13, characterized in that the material of said active layer (18, 22) has electro-optical properties.
21) Méthode selon l'une quelconque des revendications 12 ou 13, caractérisée en ce que le matériau de ladite couche active (18, 22) présente des propriétés thermo-optiques.
21) Method according to any one of claims 12 or 13, characterized in that the material of said active layer (18, 22) has thermo-optical properties.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR0017003A FR2818755B1 (en) | 2000-12-26 | 2000-12-26 | OPTICALLY ACTIVE DEVICE HAVING A CHANNEL ON AN OPTICAL SUBSTRATE |
FR0017003 | 2000-12-26 | ||
PCT/FR2001/004204 WO2002052312A1 (en) | 2000-12-26 | 2001-12-21 | Optically active waveguide device comprising a channel on an optical substrate |
Publications (1)
Publication Number | Publication Date |
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EP1346242A1 true EP1346242A1 (en) | 2003-09-24 |
Family
ID=8858179
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP01990613A Withdrawn EP1346242A1 (en) | 2000-12-26 | 2001-12-21 | Optically active waveguide device comprising a channel on an optical substrate |
Country Status (6)
Country | Link |
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US (1) | US20040091225A1 (en) |
EP (1) | EP1346242A1 (en) |
CN (1) | CN1264032C (en) |
CA (1) | CA2432815A1 (en) |
FR (1) | FR2818755B1 (en) |
WO (1) | WO2002052312A1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2818390B1 (en) * | 2000-12-15 | 2003-11-07 | Ion Beam Services | WAVEGUIDE HAVING A CHANNEL ON AN OPTICAL SUBSTRATE |
WO2005067412A2 (en) * | 2003-12-17 | 2005-07-28 | The Trustees Of Columbia University In The City Of New York | Methods for fabrication of localized membranes on single crystal substrate surfaces |
FR2871812B1 (en) * | 2004-06-16 | 2008-09-05 | Ion Beam Services Sa | IONIC IMPLANTER OPERATING IN PLASMA PULSE MODE |
ITCZ20040017A1 (en) * | 2004-11-08 | 2005-02-08 | Carlo Gavazzi Space Spa | INTEGRATED MICRO-INTERFEROMETER AND METHOD OF REALIZATION |
FR2902575B1 (en) * | 2006-06-14 | 2008-09-05 | Ion Beam Services Sa | APPARATUS FOR OPTICALLY CHARACTERIZING THE DOPING OF A SUBSTRATE |
CN104950478B (en) * | 2015-05-20 | 2017-08-01 | 吉林大学 | A kind of active composite optical wave guide based on organic polymer material and preparation method thereof |
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FR2152464B1 (en) * | 1971-09-16 | 1974-05-31 | Thomson Csf | |
US4834480A (en) * | 1988-04-21 | 1989-05-30 | Bell Communications Research, Inc. | Composite channel waveguides |
US5119460A (en) * | 1991-04-25 | 1992-06-02 | At&T Bell Laboratories | Erbium-doped planar optical device |
SE514675C2 (en) * | 1993-08-13 | 2001-04-02 | Ericsson Telefon Ab L M | Optical coupler or modulator and laser including a waveguide |
US5491768A (en) * | 1994-07-27 | 1996-02-13 | The Chinese University Of Hong Kong | Optical waveguide employing modified gallium arsenide |
JPH103100A (en) * | 1996-04-15 | 1998-01-06 | Matsushita Electric Ind Co Ltd | Optical waveguide parts, optical parts, manufacture of optical waveguide parts, and manufacture of periodic polarization inversion structure |
GB2316185B (en) * | 1996-08-10 | 1998-11-18 | Northern Telecom Ltd | Optical waveguide Bragg reflection gratings |
US6026205A (en) * | 1997-01-21 | 2000-02-15 | Molecular Optoelectronics Corporation | Compound optical waveguide and filter applications thereof |
JPH11295543A (en) * | 1998-04-15 | 1999-10-29 | Nippon Telegr & Teleph Corp <Ntt> | Production of optical waveguide |
GB2346706A (en) * | 1999-02-05 | 2000-08-16 | Univ Glasgow | Multiple core waveguide |
JP2000266952A (en) * | 1999-03-18 | 2000-09-29 | Nec Corp | Manufacture of optical wave-guide element, and optical wave-guide element |
JP3706496B2 (en) * | 1999-03-25 | 2005-10-12 | 京セラ株式会社 | Manufacturing method of optical waveguide |
FR2818390B1 (en) * | 2000-12-15 | 2003-11-07 | Ion Beam Services | WAVEGUIDE HAVING A CHANNEL ON AN OPTICAL SUBSTRATE |
US6583917B2 (en) * | 2000-12-22 | 2003-06-24 | Pirelli Cavi E Sistemi S.P.A. | Optical intensity modulation device and method |
FR2871812B1 (en) * | 2004-06-16 | 2008-09-05 | Ion Beam Services Sa | IONIC IMPLANTER OPERATING IN PLASMA PULSE MODE |
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2000
- 2000-12-26 FR FR0017003A patent/FR2818755B1/en not_active Expired - Fee Related
-
2001
- 2001-12-21 CN CNB018214010A patent/CN1264032C/en not_active Expired - Fee Related
- 2001-12-21 EP EP01990613A patent/EP1346242A1/en not_active Withdrawn
- 2001-12-21 WO PCT/FR2001/004204 patent/WO2002052312A1/en not_active Application Discontinuation
- 2001-12-21 US US10/465,973 patent/US20040091225A1/en not_active Abandoned
- 2001-12-21 CA CA002432815A patent/CA2432815A1/en not_active Abandoned
Non-Patent Citations (1)
Title |
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PASCHOTTA R.: "Planar and Channel Waveguides", INTERNET CITATION, 2008, XP001167263, Retrieved from the Internet <URL:http://spie.org/x32444.xml> [retrieved on 20100706] * |
Also Published As
Publication number | Publication date |
---|---|
CA2432815A1 (en) | 2002-07-04 |
WO2002052312A1 (en) | 2002-07-04 |
US20040091225A1 (en) | 2004-05-13 |
FR2818755B1 (en) | 2004-06-11 |
FR2818755A1 (en) | 2002-06-28 |
CN1264032C (en) | 2006-07-12 |
CN1483151A (en) | 2004-03-17 |
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