CN110783805A - Erbium silicate waveguide amplifier based on-chip pumping and preparation method thereof - Google Patents
Erbium silicate waveguide amplifier based on-chip pumping and preparation method thereof Download PDFInfo
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- H—ELECTRICITY
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- 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
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/0915—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light
- H01S3/0933—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light of a semiconductor, e.g. light emitting diode
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- H—ELECTRICITY
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- 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
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
- H01S3/16—Solid materials
- H01S3/1601—Solid materials characterised by an active (lasing) ion
- H01S3/1603—Solid materials characterised by an active (lasing) ion rare earth
- H01S3/1608—Solid materials characterised by an active (lasing) ion rare earth erbium
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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
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
- H01S3/16—Solid materials
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- H01S3/1655—Solid materials characterised by a crystal matrix silicate
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Abstract
The embodiment of the invention provides an erbium silicate waveguide amplifier based on-chip pumping and a preparation method thereof, wherein the amplifier comprises a silicon substrate, a DBR bottom reflector, a pumping light source, a gain medium layer and a DBR top reflector which are sequentially arranged on a light path, and the DBR bottom reflector and the DBR top reflector form a DBR resonant cavity; the pumping light source is used for generating pumping light through electroluminescence, and the pumping light is intersected with the transmission direction of the signal light passing through the gain medium layer; the DBR resonant cavity is used for carrying out resonance enhancement on the pump light. According to the erbium silicate waveguide amplifier and the preparation method thereof provided by the embodiment of the invention, the erbium silicate gain medium layer and the III-V family LED active layer are integrated, so that the III-V family semiconductor light source improves the electro-optic conversion efficiency, improves the light absorption and pumping efficiency of the gain material, introduces a reliable light source device for a silicon optical subsystem, and provides a high-speed and large-capacity optical signal amplification basis for the optical amplifier.
Description
Technical Field
The invention relates to the technical field of photoelectrons, in particular to an erbium silicate waveguide amplifier based on-chip pumping and a preparation method thereof.
Background
In the past decade, silicon photonics has been greatly developed, and low-loss optical waveguides, high-speed optical modulators, high-speed transceiver modules, etc. based on silicon photonics technology are gradually put into practical use, so that the application of silicon photonics technology in the fields of optical communication, data centers, etc. is gradually clear, and commercialization is entering into the implementation stage. The silicon optical technology will play a significant role in the fields of high-speed and large-capacity information transmission and processing at present and in the future, and becomes a consensus in academia and industry. Among the many functional devices constituting a silicon optical system, the technologies of optical transmission, optical detection, optical modulation and the like are basically mature. Although silicon material cannot be used as an efficient light source device, a hybrid or heterogeneous integration technology is adopted, for example, an external light source such as a III-V group laser can be integrated on a silicon optical chip to prepare the efficient light source device. With the development and progress of the technology, the functions that the silicon optical system can realize are more and more, and the system is more and more complex. The transmission and processing of optical signals in a silicon optical system inevitably results in losses. Thus, integrated optical amplification functions will become increasingly necessary in more complex silicon optical systems, but integrated optical amplification devices compatible with silicon optical technology face a number of problems and challenges.
For example: erbium doped fiber amplifiers and semiconductor optical amplifiers are common devices for the 1.55 μm communications band. However, scaling and integrating these devices with silicon photonics presents significant challenges. For erbium-doped fiber amplification materials and devices, the optical section of erbium ions is small (10)
-21cm
2) And low solid solubility: (<＝10
20cm
-3) The resulting optical gain per unit distance provided by erbium-doped fiber is so small that erbium-doped fiber typically requires several meters or more to provide sufficient gain to optical signals. When erbium-doped optical gain materials are made into optical waveguides and integrated on a silicon substrate, although the optical gain (dB/cm) per unit distance can be improved, the optical waveguides still need to be made into a spiral shape so as to have a sufficiently long operating distance and occupy an area as small as possible, which is contrary to the requirement of high-density integration. On the other hand, many erbium-doped optical gain materials are insulating media (erbium is doped into semiconductors such as silicon for many yearsBut never achieves true optical gain), the conductivity is poor, and it is difficult to perform direct electrical injection excitation, so the integrated erbium-doped optical waveguide amplifier still needs an external pump light source, which makes the optoelectronic integration scheme very complex.
If a semiconductor optical amplifier with a 1.55 μm band uses indium gallium arsenide phosphide (InGaAsP) material lattice-matched with indium phosphide (InP), its integration with a silicon optical chip faces two major difficulties: firstly, in terms of materials, the lattice mismatch of indium phosphide and silicon reaches about 8%, and the polarities are different, the direct epitaxial growth of indium phosphide and indium gallium arsenic phosphide on a silicon substrate is very difficult, the defect density of the grown materials is high, and the performance and the reliability of the manufactured photoelectric device are poor. While a high quality iii-v device can be obtained by a hybrid integration method such as bonding or thin film transfer, wafer level integration and processing are problematic because the size difference between an indium phosphide substrate (up to 3 inches) and a silicon substrate (12 inches is a mainstream in the industry) is large. Hybrid integration also faces the thermal mismatch problem of group iii-v semiconductors with silicon. Secondly, the semiconductor optical amplifier has inherent problems in performance, and because the service life of the carrier at the upper energy level is too short, the semiconductor optical amplifier can cause larger gain compression and recovery effects along with the pulse density distribution of the data stream, and the semiconductor optical amplifier has larger defects when being used for amplifying the modulated optical signal.
In summary, various bottlenecks still exist in the prior art for the development of integrated optical amplification devices.
Disclosure of Invention
In order to effectively overcome a plurality of defects of an integrated optical amplifier in the prior art, the embodiment of the invention provides an erbium silicate waveguide amplifier based on-chip pumping and a preparation method thereof.
In one aspect, an embodiment of the present invention provides an erbium silicate waveguide amplifier based on-chip pumping, including: the DBR resonant cavity comprises a silicon substrate, a DBR bottom reflector, a pumping light source, a gain medium layer and a DBR top reflector which are sequentially arranged on an optical path, wherein the DBR bottom reflector and the DBR top reflector form a DBR resonant cavity; the pumping light source is used for generating pumping light through electroluminescence, and the pumping light is intersected with the transmission direction of the signal light passing through the gain medium layer; the DBR resonant cavity is used for carrying out resonance enhancement on the pump light.
Further, the gain medium layer is an erbium silicate compound layer; the signal light is transmitted in the waveguide direction in the erbium silicate compound layer.
Furthermore, the pumping light source is a III-V group LED active layer consisting of III-V group semiconductor light sources.
Further, the above group iii-v LED active layer includes: the sandwich structure is formed by a III-V family n-type region, a III-V family quantum well region and a III-V family p-type region, wherein the III-V family quantum well region is an intermediate layer; the III-V family n-type region and the III-V family p-type region are respectively provided with an n electrode and a p electrode and used for providing pumping power for electroluminescence of the III-V family LED active layer.
Furthermore, a bonding layer is arranged between the III-V family LED active layer and the gain medium layer, and the III-V family LED active layer and the gain medium layer are bonded through the bonding layer.
Further, a III-V group laser buffer layer is arranged between the silicon substrate and the DBR top reflector.
Further, the pump light is perpendicular to the transmission direction of the signal light passing through the gain medium layer.
On the other hand, the embodiment of the invention also provides a preparation method of the erbium silicate waveguide amplifier based on-chip pumping, which comprises the following steps:
step S1, preparing an erbium-doped thin film-semiconductor light source integrated structure;
step S2, removing a first silicon substrate in the erbium-doped thin film-semiconductor light source integrated structure by combining a mechanical thinning method and a chemical corrosion method, wherein the first silicon substrate is a substrate of an erbium silicate thin film;
step S3, depositing a DBR top reflector on the upper surface of the erbium silicate film based on a plasma enhanced chemical vapor deposition method;
step S4, preparing a III-V family LED active layer in the erbium-doped thin film-semiconductor light source integrated structure into a sandwich structure consisting of a III-V family n-type region, a III-V family quantum well region and a III-V family p-type region, wherein the III-V family n-type region and the III-V family p-type region are respectively provided with an n electrode and a p electrode.
Further, the step S1 specifically includes:
step S11, depositing an erbium silicate film on a first silicon substrate based on a physical vapor deposition method, and then activating erbium ions in the erbium silicate film by high-temperature annealing;
step S12, depositing a first bonding layer on the erbium silicate film based on the plasma enhanced chemical vapor deposition method, wherein the first bonding layer is SiO
2a/SiN film;
step S13, depositing a DBR bottom reflector on a second silicon substrate based on a plasma enhanced chemical vapor deposition method;
step S14, epitaxially growing a III-V LED active layer on the upper surface of the DBR bottom reflector;
step S15, depositing a second bonding layer on the upper surface of the III-V LED active layer based on the plasma enhanced chemical vapor deposition method, wherein the second bonding layer is SiO
2a/SiN film;
step S16, polishing the first bonding layer and the surface of the first bonding layer by a chemical polishing method, and reducing the content of hydrogen and water in the bonding layer by a thermal annealing method;
and step S17, activating the surfaces of the first bonding layer and the second bonding layer based on the reactive ion etching technology, and then bonding the two layers to complete the integration of the III-V group LED active layer and the erbium silicate film.
Further, before performing the step S13, depositing a iii-v laser buffer layer on the second silicon substrate.
According to the erbium silicate waveguide amplifier based on-chip pumping and the preparation method thereof provided by the embodiment of the invention, firstly, the III-V group LED active layer heteroepitaxially grown on the silicon substrate is used as an electrical injection light source to pump the erbium silicate optical gain device, so that indirect electrical pumping erbium-doped optical amplification is realized. On one hand, the optical gain of the amplifier in unit distance is greatly improved, the size of the device is reduced, and the requirement of high-density integration is met; on the other hand, by integrating the group iii-v semiconductor material with the erbium silicate material on the same substrate, the group iii-v semiconductor material is utilized to provide efficient optical pumping for the erbium silicate material. The three components are combined, the advantages of the erbium-doped optical gain device and the III-V group semiconductor light source are fully exerted, the respective fundamental difficulties are avoided, and a new development direction is opened for the research of the silicon-based integrated optical amplifier.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a schematic diagram of an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention;
fig. 2 is a schematic three-dimensional view of an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention;
FIG. 3 is a schematic cross-sectional diagram of an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention;
FIG. 4 is a schematic structural modeling diagram of an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention;
fig. 5 is a schematic diagram of an energy level structure of a gain material (erbium-ytterbium silicate) in an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention;
FIG. 6 is a diagram illustrating simulation results of a hybrid resonator according to an embodiment of the present invention;
FIG. 7 is a graph showing the results of a spectrum test of the gain material (erbium silicate) in an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention;
fig. 8 is a schematic flow chart of a method for manufacturing an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention;
fig. 9 is a schematic flow chart illustrating a process for manufacturing an integrated structure of an erbium-doped thin film-semiconductor light source in an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention;
fig. 10 is a schematic diagram of another process flow for manufacturing an integrated structure of an erbium-doped thin film-semiconductor light source in an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention;
fig. 11 is a schematic flow chart of another process for manufacturing an integrated structure of an erbium-doped thin film-semiconductor light source in an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Currently, silicon photon technology has entered into a mature stage, but reliable silicon-based light sources such as lasers and optical amplifiers are still short boards; in addition, erbium-doped materials are well-known materials suitable for optical amplifiers, but erbium-doped optical amplifiers cannot be directly electrically pumped.
In view of the deficiencies in the prior art, embodiments of the present invention provide an erbium silicate waveguide amplifier based on-chip pumping, as shown in fig. 1, including but not limited to: a silicon substrate (Si substrate), a DBR bottom reflector (DBR bottom reflector), a pump light source (980nm III-V LED), a gain medium layer (dielectric waveguide) and a DBR top reflector (DBR top reflector) which are arranged on an optical path in sequence; the DBR bottom reflector and the DBR top reflector form a DBR resonant cavity; the pump light source is used for generating pump light (980pumplight) through electroluminescence, and the generated pump light is intersected with the transmission direction of the signal light passing through the gain medium layer; the DBR resonant cavity is used for carrying out resonance enhancement on pump light.
For convenience of description, in all embodiments of the present invention, the example of performing waveguide amplification on signal light with a wavelength of 1535nm by using pump light with a wavelength of 980nm is described, but the present invention is not limited to the scope of the embodiments of the present invention.
Specifically, in the erbium silicate waveguide amplifier based on-chip pumping provided by the embodiment of the invention, the silicon substrate is arranged on a plane formed by an X axis and a Y axis; the pumping light source for generating pumping light is a layered structure and is uniformly paved on the upper surface of the silicon substrate, and the generated pumping light is transmitted towards the direction far away from the silicon substrate along the Z-axis direction. The gain medium layer is bonded with the upper surface of the pumping light source, and the generated pumping light can be used for pumping the optical waveguide structure of the gain medium layer by performing electroluminescence processing on the pumping light source, so that the signal light in the gain medium layer is amplified, and the amplified signal light (amplified signal light) is obtained.
In view of the need to improve the absorption efficiency of the pump light and the light emission intensity of the pump light source in order to further improve the stimulated radiation efficiency in the gain medium layer, in the embodiment of the present invention, the bonding structure formed by the pump light source and the gain medium layer is disposed in the pump resonant cavity to achieve the above object. In this embodiment, the resonant cavity adopts a Distributed Bragg Reflector (DBR) structure, which only generates strong resonance for the pump light but does not resonate for the signal light, so that the pump light is reflected multiple times in the resonant cavity to enhance the absorption of carriers, and a wider gain spectrum can be maintained for the signal light. The gain cavity comprises a DBR bottom reflector arranged between a silicon substrate and a pumping light source and a DBR top reflector arranged on the upper surface of a gain medium layer. The DBR resonant cavity is constructed to perform resonance enhancement on pump light with the wavelength of 980nm in the Z-axis direction in the resonant cavity.
The DBR resonant cavity is used as an assistant, so that the pumping light intensity of the pumping light source can be improved, and the pumping absorption enhancement effect on the gain medium can be realized. For example, a conventional DBR cavity, considering that the reflectivities of the two DBR mirrors as constituent elements are 99.8% and 99.5%, respectively, the resonance absorption enhancement coefficient can reach 460dB/cm, and the absorption efficiency can be improved by two orders of magnitude, so that the excitation intensity of the gain material can be further enhanced.
The erbium silicate waveguide amplifier based on-chip pumping provided by the embodiment of the invention uses the pumping light source active layer which is heteroepitaxially grown on the silicon substrate as an electrical injection light source to pump the erbium silicate optical gain device on the same silicon substrate, thereby realizing indirect electrical pumping erbium-doped optical amplification. On one hand, the optical gain of the amplifier in unit distance is greatly improved, the size of the device is reduced, and the requirement of high-density integration is met; on the other hand, the pumping light source and the gain medium are integrated on the same substrate, and the pumping light source is utilized to provide efficient optical pumping for the material of the gain medium layer. The advantages of the gain medium layer and the pump light source are fully exerted, the respective fundamental difficulties are avoided, and a new development direction is opened up for the research of the silicon-based integrated optical amplifier.
Based on the content of the above embodiment, as an optional embodiment, the gain medium layer is an erbium silicate compound layer, and the upper and lower surfaces of the gain medium layer are silicon nitride layers; the signal light is transmitted along a waveguide direction in the waveguide structure.
Specifically, as shown in fig. 1 and 2, although the monolithic erbium (Er) -doped silicon-based laser in the present stage has the advantages of temperature insensitivity, long luminescence lifetime, low noise and compatibility with Complementary Metal Oxide Semiconductor (CMOS) technology, due to the limitation of solid solubility, the erbium concentration in the erbium-doped medium can only reach-10 at the maximum
20cm
-3The highest gain can only reach 2-5 dB/cm, so that the further improvement of the output performance of the laser is limited. To further improve the gain characteristics of the material, it is necessary to increase the erbium concentration in the erbium-doped medium.
On the other hand, the current silicon-based erbium-doped laser has high requirements on pumping efficiency and pumping power, so that the cavity linewidth of DBR resonance is strictly limited by the length and loss factor of a resonator, and the cavity feedback is still at a lower level, high-quality narrow linewidth laser output cannot be realized, and the requirements on a silicon-based optoelectronic chip cannot be met.
In this embodiment, the gain medium layer is a waveguide structure formed by alternating silicon nitride layers and erbium silicate layers. Ytterbium ions can be introduced into the erbium silicate material to optimize the amplification characteristic of the material, on one hand, the ytterbium ions and the erbium ions have similar ion radii, the distance between the erbium ions can be properly increased, and the non-radiative energy transfer process between the erbium ions is inhibited; on the other hand, the absorption cross section of ytterbium ion to pump light is one order of magnitude higher than that of erbium ion, and the ytterbium ion has strong sensitization effect on the pump light absorption of erbium ion. The gain medium layer made of erbium-ytterbium co-doped silicate compound material can improve the concentration of erbium ions by one to two orders of magnitude, and the maximum concentration can reach 10 to 10 under the condition of no influence of solid solubility
22cm
-3And the doping of ytterbium ion can improve the absorption cross section of the material to the pump light by one order of magnitude, and the maximum absorption cross section can reach 10 to below
22cm
-3And the doping of ytterbium ion can improve the absorption cross section of the material to the pump light by one order of magnitude, and the characteristics greatly improve the optical gain of the amplifier per unit distance to 10
2dB/cm, thereby further improving the performances of the laser such as output power, conversion efficiency and the like, reducing the size of the device and meeting the requirement of high-density integration.
Moreover, due to the low loss characteristic of silicon nitride (silicon nitride has a higher refractive index than Er silicate), the erbium silicate and the silicon nitride form an alternate mixed thin film structure, so that the transmission loss during waveguide transmission can be effectively reduced, and the net gain of the material is improved. In addition, the silicon nitride layer can also be used as a thermal expansion buffer layer, and the thermal expansion coefficient of the silicon nitride layer is between that of the substrate and the erbium silicate, so that the erbium silicate-silicon nitride alternate mixed film can effectively inhibit the stress generated by the film after high-temperature annealing and reduce the surface loss.
The thickness and number of layers of the erbium silicate film and the silicon nitride sub-layer can be respectively optimized in the embodiment of the invention, so that the pump and signal modes in the gain layer have higher limiting factors to provide enough gain and lower waveguide loss.
Based on the above description of the embodiments, as an alternative embodiment, the pumping light source can be a iii-v LED active layer composed of iii-v semiconductor light sources.
The wider spectrum of the common pumping light source causes the pumping efficiency of the erbium silicate gain medium layer to be low, so how to effectively compress the spectral width of the pumping light and improve the light absorption and pumping efficiency of the erbium silicate gain material is the key to whether the low pumping threshold can be realized.
In the embodiment of the invention, the pumping light source is set as a III-V group LED active layer consisting of III-V group semiconductor light sources. A semiconductor composed of group iii elements and group v elements in the periodic table is called a group iii-v compound semiconductor. The group iii-v LED active layer used in embodiments of the invention may be any of GaAs, GaP, InP and InSb, but is preferably GaAs, and since GaAs is grown epitaxially on silicon with a lower defect density than InP and the like, a silicon-based GaAs based electrical injection light source (e.g., LED) is more reliable than silicon-based InP and the like.
Based on the above description of the embodiments, as an alternative embodiment, as shown in fig. 3, the active layer of the iii-v LED includes: the sandwich structure is formed by a III-V family n type region (n-type III-V), a III-V family quantum well region (III-V MQW) and a III-V family p type region (p-type III-V), wherein the III-V family quantum well region is an intermediate layer. The III-V family n-type region and the III-V family p-type region are respectively provided with an n electrode (n electrode) and a p electrode (p electrode) for providing a pumping power supply for electroluminescence of the III-V family LED active layer.
In the embodiment of the invention, the III-V family p-type region and the III-V family n-type region are not specifically limited to be positioned on the upper surface or the lower surface of the III-V family quantum well region and have various thicknesses, but the III-V family p-type region and the III-V family n-type region are required to be sequentially bonded to form a sandwich structure, wherein the III-V family quantum well region is positioned on the middle layer. The plane formed by the three components is positioned on the plane formed by the X axis and the Y axis (namely, a horizontal plane).
Further, in order to facilitate the electro-stimulation of the III-V LED active layer, an electrode n is arranged in the III-V n-type region, and the electrode protrudes out of the surface of the III-V n-type region; similarly, an electrode p is also provided in the group III-V p-type region. If a pumping voltage is applied between the electrode n and the electrode p, corresponding pumping light is generated in the III-V family quantum well region.
Based on the content of the above embodiments, as shown in fig. 2 and fig. 3, as an alternative embodiment, a bonding layer (bondlayer) is further disposed between the group iii-v LED active layer and the gain medium layer, and the group iii-v LED active layer and the gain medium layer are bonded through the bonding layer.
Specifically, the bonding layer may be SiO
2The first bonding layer positioned on the lower surface of the erbium silicate film and the second bonding layer positioned on the upper surface of the pumping light source are bonded by using a wafer bonding method, and the erbium silicate medium layer and the pumping light source are integrated into a whole by the bonding layer generated after bonding, so that the bonding strength is effectively improved.
Based on the content of the above embodiments, as shown in fig. 2 and fig. 3, in the present embodiment, a iii-v laser buffer layer (buffer layer) is further disposed between the silicon substrate and the DBR top mirror.
Wherein the laser buffer layer may be SiO
2The film-shaped structural layer formed by/SiN can effectively isolate the leakage of the pumping light source from the plane where the pumping light source is located, and the pumping efficiency is improved.
Based on the content of the above embodiments, further, in the present embodiment, the pump light is perpendicular to the transmission direction of the signal light passing through the gain medium layer.
Specifically, in this embodiment, as shown in fig. 4, the DBR cavity formed by the DBR bottom mirror (bottom-DBR) and the DBR top mirror (top-DBR) is vertical (i.e., Z-axis direction), the erbium silicate gain material (Er silicate waveguide) located in the DBR cavity has an optical waveguide effect on the signal light in the horizontal direction, and the pump light (980nm pump in) generated by the pump light source (pumping) is repeatedly reflected in the cavity to generate resonance, so that optical gain can be obtained when the signal light (1535nm signal in) horizontally passes through the erbium silicate waveguide. The absorption efficiency of the silicate material to the pump light and the luminous intensity of the LED light source can be further improved.
It should be noted that, the mutual influence between the resonant cavity and the optical waveguide is obtained by performing simulation design and optimization on the optical field distribution in the resonant cavity and in the optical waveguide provided in this embodiment, so that the resonant cavity has a strong absorption enhancement effect on the erbium-doped material, and the loss of the optical waveguide is small.
Further, fig. 5 is a schematic diagram of an energy level structure of a gain material (erbium-ytterbium silicate) in an on-chip pumping-based erbium silicate waveguide amplifier, in which erbium ions and ytterbium ions are based on a five-energy-level-two-energy-level system model, and the model relates to various energy level transition processes, including transition processes that promote optical amplification such as ground-state absorption, stimulated emission, and transition processes that suppress optical amplification such as excited-state absorption, cooperative up-conversion, cross relaxation, spontaneous emission, and the like. According to the erbium-ytterbium energy level structure model, rate equations of erbium ions and ytterbium ions distributed at different energy levels can be obtained:
wherein A is
ij＝1/τ
21Description of spontaneous radiative and non-radiative relaxation probabilities (τ)
21Indicating the lifetime between level i and level j). C
2And C
3For first and second order co-up-conversion coefficients, C
14Is Er
3+Cross relaxation coefficient, K
trIs Yb
3+To Er
3+Coefficient of energy transfer, N
ErAnd N
YbAre respectively Er
3+And Yb
3+Concentration, W
12/W
21For stimulated emission and absorption transition speed of signal lightRate, R
13/R
31Indicating the stimulated emission and absorption transition rates for the pump light.
Further, fig. 4 is a simulation diagram of modeling an erbium silicate waveguide amplifier based on-chip pumping according to an embodiment of the present invention, as shown in fig. 4, the pump light power varies along the x direction, the signal light power varies along the z direction, and since the pump light simultaneously propagates in the forward direction and in the reverse direction in the vertical resonant cavity (x direction), the propagation equation of the pump should change in two directions. The transmission equation of the pump light and the signal light is as follows:
by combining the rate equation and the transmission equation, the amplification characteristics of the erbium silicate waveguide amplifier can be predicted and revised.
Fig. 6 is a schematic diagram of simulation results of the erbium silicate waveguide amplifier based on-chip pumping provided in this embodiment, and as can be seen from fig. 6, when the gain medium layer is pumped by using pump light sources with pump powers of 150mW, 100mW and 50mW, simulation curves are L1, L2 and L3, respectively, from which it can be known that: when the power of the pumping light source is larger, the signal amplification effect of the erbium silicate waveguide amplifier is stronger.
Fig. 7 is a graph showing the results of the spectrum test of the gain material (erbium-ytterbium silicate) in the erbium silicate waveguide amplifier based on-chip pumping according to the embodiment of the present invention, and it can be seen from fig. 7 that the erbium-ytterbium silicate thin film has a wider gain spectrum around the wavelength of 1.5 μm due to the photoluminescence performance. The thickness of the gain material can be designed accordingly.
Fig. 8 is a schematic flow chart of a process for manufacturing an integrated structure of an erbium-doped thin film-semiconductor light source in an on-chip pumping-based erbium silicate waveguide amplifier according to an embodiment of the present invention, and as shown in fig. 8 and fig. 11, a method for manufacturing an on-chip pumping-based erbium silicate waveguide amplifier according to an embodiment of the present invention includes, but is not limited to, the following steps:
step S1, preparing an erbium-doped thin film-semiconductor light source integrated structure;
step S2, removing a first silicon substrate in the erbium-doped thin film-semiconductor light source integrated structure by combining a mechanical thinning method and a chemical corrosion method, wherein the first silicon substrate is a substrate of an erbium silicate thin film;
step S3, depositing a DBR top reflector on the upper surface of the erbium silicate film based on a plasma enhanced chemical vapor deposition method;
step S4, preparing the III-V family LED active layer in the erbium-doped thin film-semiconductor light source integrated structure into a sandwich structure consisting of a III-V family n-type region, a III-V family quantum well region and a III-V family p-type region, wherein the III-V family n-type region and the III-V family p-type region are respectively provided with an n electrode and a p electrode.
As shown in fig. 9 and 10, an embodiment of the present invention further provides a method for integrating an active layer of a iii-v LED with the erbium silicate film, that is, a method for preparing an integrated structure of an erbium-doped thin film-semiconductor light source in step 1, including, but not limited to, the following steps:
step S11, depositing an erbium silicate film on a first silicon substrate based on a physical vapor deposition method, and then activating erbium ions in the erbium silicate film by high-temperature annealing;
step S12, depositing a first bonding layer on the erbium silicate film based on the plasma enhanced chemical vapor deposition method, wherein the first bonding layer is SiO
2a/SiN film;
step S13, depositing a DBR bottom reflector on a second silicon substrate based on a plasma enhanced chemical vapor deposition method;
step S14, epitaxially growing a III-V LED active layer on the upper surface of the DBR bottom reflector;
step S15, depositing a second bonding layer on the upper surface of the III-V LED active layer based on the plasma enhanced chemical vapor deposition method, wherein the second bonding layer is SiO
2a/SiN film;
step S16, after the first bonding layer and the surface of the first bonding layer are polished by a chemical polishing method, the content of hydrogen and water in the bonding layer is reduced by a thermal annealing method;
and step S17, activating the surfaces of the first bonding layer and the second bonding layer based on the reactive ion etching technology, and then bonding the two layers to complete the integration of the III-V group LED active layer and the erbium silicate film.
The steps described above are now described with reference to fig. 10 and fig. 11, but only as a specific example, and in the steps shown, some of the steps that may be changed in sequence are not specifically limited.
First, an erbium silicate film and a DBR bottom mirror are deposited on two different silicon substrates (a first silicon substrate and a second silicon substrate), respectively. The method in which the erbium silicate thin film is deposited on the first silicon substrate may utilize a physical vapor deposition method; the method of depositing the DBR bottom mirror on the second silicon substrate may be a vapor deposition method using plasma enhanced chemistry.
Further, after the erbium silicate film is manufactured, erbium ions in the erbium silicate film can be activated through a high-temperature annealing method, so that the pumping efficiency is further improved.
And further epitaxially growing a III-V group LED active layer on the upper surface of the DBR bottom reflector, wherein the III-V group LED active layer comprises a III-V group n-type region, a III-V group quantum well region and a III-V group p-type region which are sequentially grown, or a III-V group p-type region, a III-V group quantum well region and a III-V group n-type region which are sequentially grown.
Further, a bonding layer (defined as a first bonding layer and a second bonding layer) is deposited on the upper surface of the silicate film and the upper surface of the active layer of the iii-v LED, respectively, wherein the deposition method may be a vapor deposition method using plasma enhanced chemistry.
And further, carrying out chemical mechanical polishing treatment on the two bonding layers to enable the roughness of the surfaces to meet the bonding requirement. The content of hydrogen and water in the bonding layer can be reduced by simultaneously utilizing a thermal annealing method so as to further improve the bonding strength.
And finally, performing further activation treatment on the two surfaces by using a Reactive Ion Etching (RIE) technology, inverting the obtained silicate film (comprising the first bonding layer), bonding the first bonding layer and the second bonding layer, and fusing the two bonding layers into a whole by using a bonding device (such as a forging device) to obtain the bonded erbium-doped film-semiconductor light source integrated structure.
Furthermore, the original substrate outside the erbium silicate film in the erbium-doped film-semiconductor light source integrated structure is removed by using a mechanical thinning method or a chemical etching method so as to reduce the size of the device, and the DBR top reflector is deposited at the position of the original substrate, wherein the deposition method can also be a vapor deposition method based on plasma enhanced chemistry to generate a DBR resonant cavity formed by the DBR top reflector and the DBR bottom reflector.
Further, by using the conventional methods such as photolithography and etching, two electrodes of the iii-v LED active layer are etched on the basis of the prepared semi-finished product, which is not described in detail in this embodiment.
Based on the disclosure of the foregoing embodiment, as an alternative embodiment, before performing step S13, depositing a group iii-v laser buffer layer on the second silicon substrate is further included. After the deposition of the DBR bottom reflector is completed, a III-V group laser buffer layer is deposited on the upper surface of the DBR bottom reflector, the III-V group laser buffer layer can effectively prevent the leakage of pump light in a resonant cavity, and the amplification efficiency is improved.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. An erbium silicate waveguide amplifier based on-chip pumping, comprising: the laser diode comprises a silicon substrate, a DBR bottom reflector, a pumping light source, a gain medium layer and a DBR top reflector which are sequentially arranged on an optical path, wherein the DBR bottom reflector and the DBR top reflector form a DBR resonant cavity;
the pumping light source is used for generating pumping light through electroluminescence, and the pumping light is intersected with the transmission direction of the signal light passing through the gain medium layer;
the DBR resonant cavity is used for carrying out resonance enhancement on the pump light.
2. An erbium silicate waveguide amplifier based on-chip pumping according to claim 1 wherein the gain medium layer is an erbium silicate compound layer; the signal light is transmitted in a waveguide direction in the erbium silicate compound layer.
3. An erbium silicate waveguide amplifier based on-chip pumping according to claim 1 wherein the pumping light source is a group iii-v LED active layer composed of group iii-v semiconductor light sources.
4. An on-chip pumping based erbium silicate waveguide amplifier according to claim 3, characterized in that the group III-V LED active layers comprise: the sandwich structure is formed by a III-V family n-type region, a III-V family quantum well region and a III-V family p-type region, wherein the III-V family quantum well region is an intermediate layer;
and the III-V family n-type region and the III-V family p-type region are respectively provided with an n electrode and a p electrode and used for providing pumping power supply for electroluminescence of the III-V family LED active layer.
5. The on-chip pumping based erbium silicate waveguide amplifier according to claim 3, wherein a bonding layer is further disposed between the group III-V LED active layer and the gain medium layer, and the group III-V LED active layer and the gain medium layer are bonded through the bonding layer.
6. An on-chip pumping based erbium silicate waveguide amplifier according to claim 1, characterized in that a iii-v laser buffer layer is provided intermediate the silicon substrate and the DBR top mirror.
7. An erbium silicate waveguide amplifier based on-chip pumping according to claim 1, wherein the pump light is perpendicular to the direction of transmission of the signal light through the gain medium layer.
8. A preparation method of an erbium silicate waveguide amplifier based on-chip pumping is characterized by comprising the following steps:
step S1, preparing an erbium-doped thin film-semiconductor light source integrated structure;
step S2, removing a first silicon substrate in the erbium-doped thin film-semiconductor light source integrated structure by combining a mechanical thinning method and a chemical corrosion method, wherein the first silicon substrate is a substrate of an erbium silicate thin film;
step S3, depositing a DBR top reflector on the upper surface of the erbium silicate film based on a plasma enhanced chemical vapor deposition method;
step S4, preparing the III-V family LED active layer in the erbium-doped thin film-semiconductor light source integrated structure into a sandwich structure consisting of a III-V family n-type region, a III-V family quantum well region and a III-V family p-type region, wherein the III-V family n-type region and the III-V family p-type region are respectively provided with an n electrode and a p electrode.
9. The method of manufacturing an on-chip pumping based erbium silicate waveguide amplifier according to claim 8, wherein the step S1 comprises:
step S11, depositing the erbium silicate film on the first silicon substrate based on a physical vapor deposition method, and then activating erbium ions in the erbium silicate film by using a high-temperature annealing method;
step S12, depositing a first bonding layer on the erbium silicate film based on a plasma enhanced chemical vapor deposition method, wherein the first bonding layer is SiO
2a/SiN film;
step S13, depositing a DBR bottom reflector on a second silicon substrate based on a plasma enhanced chemical vapor deposition method;
step S14, epitaxially growing the III-V LED active layer on the upper surface of the DBR bottom reflector;
step S15, depositing a second bonding layer on the upper surface of the III-V LED active layer based on the plasma enhanced chemical vapor deposition method, wherein the second bonding layer is SiO
2a/SiN film;
step S16, after the first bonding layer and the surface of the first bonding layer are polished by a chemical polishing method, the content of hydrogen and water in the bonding layer is reduced by a thermal annealing method;
step S17, based on the reactive ion etching technique, activating the surfaces of the first bonding layer and the second bonding layer, and then bonding the two layers to complete the integration of the iii-v LED active layer and the erbium silicate film.
10. The method of fabricating an erbium silicate waveguide amplifier based on-chip pumping according to claim 9,
further comprising, prior to performing the step S13, depositing a group iii-v laser buffer layer on the second silicon substrate.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111934196A (en) * | 2020-06-28 | 2020-11-13 | 北京大学 | Electrically-driven on-chip integrated erbium-doped waveguide amplifier and preparation method thereof |
| CN111987575A (en) * | 2020-07-23 | 2020-11-24 | 中山大学 | Hybrid integration method of erbium-doped optical waveguide amplifier of on-chip indirect electric pump |
| CN112505976A (en) * | 2021-02-03 | 2021-03-16 | 深圳市汇海鑫科技有限公司 | Optical signal amplification method |
| CN113594852A (en) * | 2021-09-29 | 2021-11-02 | 苏州长光华芯光电技术股份有限公司 | Narrow-linewidth semiconductor device and preparation method thereof |
| CN116107131A (en) * | 2023-02-13 | 2023-05-12 | 中山大学 | Preparation method of gain substrate type optical waveguide amplifier and optical waveguide amplifier |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5796771A (en) * | 1996-08-19 | 1998-08-18 | The Regents Of The University Of California | Miniature self-pumped monolithically integrated solid state laser |
| US20050141078A1 (en) * | 2003-12-30 | 2005-06-30 | Jung Sun-Tae | Optical signal amplifier, optical communication module comprising same and method for fabricating same |
| CN1778021A (en) * | 2003-03-21 | 2006-05-24 | 英特尔公司 | System and method for an improved light-emitting device |
| US20090284830A1 (en) * | 2008-05-16 | 2009-11-19 | Samsung Electronics Co., Ltd. | Optical amplifying medium, method of manufacturing the optical amplifying medium, and optical device comprising the optical amplifying medium |
| EP2538505A2 (en) * | 2011-06-23 | 2012-12-26 | Raytheon Company | System and method for suppressing parasitics in an optical device |
| US20170018902A1 (en) * | 2015-07-14 | 2017-01-19 | International Business Machines Corporation | Monolithically integrated laser with led pump |
| WO2018085509A1 (en) * | 2016-11-07 | 2018-05-11 | Dicon Fiberoptics, Inc. | Solid-state optical amplifier having an active core and doped cladding in a single chip |
| CN108683079A (en) * | 2013-07-03 | 2018-10-19 | 英菲尼斯有限责任公司 | Wavelength-tunable vertical-cavity surface emitting laser for swept-source optical coherence chromatographic imaging system |
-
2019
- 2019-11-01 CN CN201911060974.8A patent/CN110783805B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5796771A (en) * | 1996-08-19 | 1998-08-18 | The Regents Of The University Of California | Miniature self-pumped monolithically integrated solid state laser |
| CN1778021A (en) * | 2003-03-21 | 2006-05-24 | 英特尔公司 | System and method for an improved light-emitting device |
| US20050141078A1 (en) * | 2003-12-30 | 2005-06-30 | Jung Sun-Tae | Optical signal amplifier, optical communication module comprising same and method for fabricating same |
| US20090284830A1 (en) * | 2008-05-16 | 2009-11-19 | Samsung Electronics Co., Ltd. | Optical amplifying medium, method of manufacturing the optical amplifying medium, and optical device comprising the optical amplifying medium |
| EP2538505A2 (en) * | 2011-06-23 | 2012-12-26 | Raytheon Company | System and method for suppressing parasitics in an optical device |
| CN108683079A (en) * | 2013-07-03 | 2018-10-19 | 英菲尼斯有限责任公司 | Wavelength-tunable vertical-cavity surface emitting laser for swept-source optical coherence chromatographic imaging system |
| US20170018902A1 (en) * | 2015-07-14 | 2017-01-19 | International Business Machines Corporation | Monolithically integrated laser with led pump |
| WO2018085509A1 (en) * | 2016-11-07 | 2018-05-11 | Dicon Fiberoptics, Inc. | Solid-state optical amplifier having an active core and doped cladding in a single chip |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111934196A (en) * | 2020-06-28 | 2020-11-13 | 北京大学 | Electrically-driven on-chip integrated erbium-doped waveguide amplifier and preparation method thereof |
| CN111934196B (en) * | 2020-06-28 | 2021-12-10 | 北京大学 | Electrically-driven on-chip integrated erbium-doped waveguide amplifier and preparation method thereof |
| CN111987575A (en) * | 2020-07-23 | 2020-11-24 | 中山大学 | Hybrid integration method of erbium-doped optical waveguide amplifier of on-chip indirect electric pump |
| CN111987575B (en) * | 2020-07-23 | 2022-02-18 | 中山大学 | Hybrid integration method of erbium-doped optical waveguide amplifier of on-chip indirect electric pump |
| CN112505976A (en) * | 2021-02-03 | 2021-03-16 | 深圳市汇海鑫科技有限公司 | Optical signal amplification method |
| CN112505976B (en) * | 2021-02-03 | 2021-08-10 | 深圳市汇海鑫科技有限公司 | Optical signal amplification method |
| CN113594852A (en) * | 2021-09-29 | 2021-11-02 | 苏州长光华芯光电技术股份有限公司 | Narrow-linewidth semiconductor device and preparation method thereof |
| CN116107131A (en) * | 2023-02-13 | 2023-05-12 | 中山大学 | Preparation method of gain substrate type optical waveguide amplifier and optical waveguide amplifier |
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