CN102177455A - Optical transmission/reception module - Google Patents
Optical transmission/reception module Download PDFInfo
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- CN102177455A CN102177455A CN200980130330.XA CN200980130330A CN102177455A CN 102177455 A CN102177455 A CN 102177455A CN 200980130330 A CN200980130330 A CN 200980130330A CN 102177455 A CN102177455 A CN 102177455A
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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
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
- G02B6/4215—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms the intermediate optical elements being wavelength selective optical elements, e.g. variable wavelength optical modules or wavelength lockers
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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
- G02B6/14—Mode converters
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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
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02057—Optical fibres with cladding with or without a coating comprising gratings
- G02B6/02076—Refractive index modulation gratings, e.g. Bragg gratings
- G02B6/0208—Refractive index modulation gratings, e.g. Bragg gratings characterised by their structure, wavelength response
- G02B6/02085—Refractive index modulation gratings, e.g. Bragg gratings characterised by their structure, wavelength response characterised by the grating profile, e.g. chirped, apodised, tilted, helical
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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
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
- G02B6/4207—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms with optical elements reducing the sensitivity to optical feedback
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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
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
- G02B6/4214—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device
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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
- H01S5/02—Structural details or components not essential to laser action
- H01S5/022—Mountings; Housings
- H01S5/0225—Out-coupling of light
- H01S5/02251—Out-coupling of light using optical fibres
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- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Couplings Of Light Guides (AREA)
- Optical Communication System (AREA)
- Semiconductor Lasers (AREA)
Abstract
An optical transmission/reception module which can ensure the transmission quality without providing a collimating optical device and a narrow-band filter. A fiber (7) with a grating which has a function of the narrow-band filter to block transmission of an optical signal in a band other than a narrow band containing a wavelength of 1310 nm, a narrow band containing a wavelength of 1490 nm, and a narrow band containing a wavelength of 1550 nm is used as an optical fiber for transmitting an optical signal with the wavelength of 1310 nm that has passed through WDM filters (4, 5) to a station and transmitting optical signals with the wavelengths of 1490 nm and 1550 nm transmitted from the station to the WDM filter (5).
Description
Technical field
The present invention relates to a kind of light transmitting receiving module, it uses optical fiber, be equipped in the entrant provides entrant's sidelight line termination device (ONU:Optical Network Unit) of GE-PON (Gigabit Ethernet (registered trademark)-Passive Optical Network System) of maximum transfer speed 1G bps Internet service, and to carry out converting optical signals be the processing of electric signal and be the processing of light signal with converting electrical signal.
Background technology
The GE-PON system by the station sidelight line termination device that is arranged on central station (OLT:Optical Line Terminal), make the transmission path maximum branch become 32 optical branching device and be arranged on entrant's entrant's sidelight line termination device within doors and constitute.
Downlink data/voice signal of being transferred to entrant's sidelight line termination device for slave station sidelight line termination device distributes the wavelength of 1490nm, distributes the wavelength of 1550nm for descending analog video signal.
On the other hand, give the wavelength that transmits the upstream data. signals distribution 1310nm of the sidelight line termination device that arrives at a station from entrant's sidelight line termination device.
Like this, the GE-PON system uses and distributes the wavelength multiplexing mode (WDM:Wavelength Division Multiplexing) of a plurality of wavelength to carry out the uni-core bidirectional optical communication.
But, in the GE-PON system, be necessary in the optical wavelength frequency band of the optical wavelength of downlink data/voice signal and analog video signal, guard band to be set.That is, for fear of sending the frequency band optical wavelength in addition that receives these optical wavelength, entrant's sidelight line termination device is necessary to use the light transmitting receiving module that guard band is set.
As mentioned above, though entrant's sidelight line termination device is necessary to use the light transmitting receiving module that guard band is set, but, for example in patent documentation 1 in the disclosed sending/receiving module, by using the WDM wave filter, the light signal that separates multiplexed a plurality of wavelength is realized the uni-core bidirectional optical communication.But, in this sending/receiving module, only only by being connected the Lens Coupling optical element between WDM wave filter and the optical fiber, can not being applicable near the GE-PON system of the guard band of the optical wavelength that is provided with the optical wavelength that is adjacent to downlink data/voice signal and analog video signal.
Here, Figure 14 is the key diagram based on the filter characteristic of diffusion light (diverging light) of disclosed receiver module in the expression patent documentation 1.Rectangle part implication among Figure 14 is a standard format.
As can be seen from Figure 14, under the situation of the narrow band filter of the light transmitting receiving module inside that diffusion light is incided be positioned at entrant's sidelight line termination device, the diffusion light of light transmitting receiving module is passed through guard band (wavestrip λ 1-α).
Here, under the situation of the optical wavelength adjacency of the optical wavelength of guard band and data/voice signal or analog video signal, owing to depend on the incident light angle of this narrow band filter relatively, the filter characteristic of narrow band filter changes, so be necessary to keep the filter characteristic of narrow band filter, guarantee transmission quality.
In order to keep the filter characteristic of narrow band filter, guarantee transmission quality, as long as the collimating optics equipment etc. that the diffusion light from optical fiber output is transformed to directional light (collimated light) is set, the angle of adjusting the relative narrow band filter of incident light gets final product.
For example, the sending/receiving module that is provided with narrow band filter and collimating optics equipment is disclosed in the patent documentation 2.
Here, Figure 15 represents that disclosed sending/receiving module is based on the key diagram of the filter characteristic of directional light in the patent documentation 2.Rectangle part implication among Figure 15 is a standard format.
As can be seen from Figure 15, the guard band of wavestrip (λ 1-α), λ 1, (λ 1+ α) is set, can avoids sending the unwanted optical wavelength of reception.
In addition, the wavelength filter as low reflection and the high transmission loss more than the 40dB discloses the structure that makes after inclined optical fiber grating and non-inclined optical fiber grating make up in the patent documentation 3.Only be difficult for obtaining the characteristic of low reflection and the high transmission loss more than the 40dB, but, then can obtain the characteristic of the above high transmission loss of low reflection and 40dB by making inclination and the combination of non-inclined optical fiber grating with the transmission loss about 20dB by oblique raster.
Up to the present also do not report the structure of the light transmitting receiving module that uses this optical fiber type wavelength filter.
Patent documentation 1: (Fig. 2 a) for Japanese Unexamined Patent Application Publication 2003-524789 communique
Patent documentation 2: TOHKEMY 2005-260220 communique (segment number ［ 0009 ］, ［ 0010 ］, Fig. 4)
Patent documentation 3: No. the 3612780th, Japan's special permission.
Because existing light transmitting receiving module constitutes as mentioned above,, guarantee transmission quality so, then can keep the filter characteristic of narrow band filter if collimating optics equipment is set.But components number increases with collimating optics equipment is set.Therefore, there is the problem be difficult to that miniaturization and component costs also uprise etc.
In addition, the existing wavelength filter that uses fiber grating, when in order to obtain the high transmission loss about 20dB and to strengthen exposure intensity at inclined optical fiber grating, then be easy to generate the residual reflection under Bragg reflection wavestrip or the loss wavestrip, there is the problem that can damage low reflection characteristic.
Summary of the invention
The present invention makes in order to solve above-mentioned problem, and its purpose is to provide a kind of light transmitting receiving module, and collimating optics equipment or narrow band filter are not set, and just can guarantee transmission quality.
Light transmitting receiving module of the present invention, as when the optical signal transmission that will be separated the 1st wavestrip that multiplexed unit sees through by filtering is arrived at a station side, the optical signal transmission of the 2nd and the 3rd wavestrip that the slave station side is sent is to the optical fiber of Wavelength separation multiplex Multiplexing Unit, use grating belt optical fiber, this grating belt optical fiber stops the seeing through of light signal of the frequency band beyond the 1st, the 2nd and the 3rd wavestrip, and has the function of narrow band filter.
The invention effect
According to the present invention, owing to constitute, as when the optical signal transmission that will be separated the 1st wavestrip that multiplexed unit sees through by filtering is arrived at a station side, the optical signal transmission of the 2nd and the 3rd wavestrip that the slave station side is sent is to the optical fiber of Wavelength separation multiplex Multiplexing Unit, use grating belt optical fiber, this grating belt optical fiber stops the 1st, seeing through of the light signal of the frequency band beyond the 2nd and the 3rd wavestrip, and has a function of narrow band filter, so collimating optics equipment or narrow band filter needn't be set, just can guarantee transmission quality, its result has the effect that can realize that miniaturization and component costs reduce.
Description of drawings
Fig. 1 is the key diagram of expression according to the structure of the light transmitting receiving module of embodiment 1.
Fig. 2 is the key diagram of expression fiber grating characteristic.
Fig. 3 is the key diagram of expression according to the structure of the light transmitting receiving module of embodiment 2.
Fig. 4 is the key diagram of expression according to the structure of the light transmitting receiving module of embodiment 3.
Fig. 5 is the key diagram of expression according to the structure of the light transmitting receiving module of embodiment 4.
Fig. 6 is the structure of fiber grating is used in expression according to the light transmitting receiving module of embodiment 5 a key diagram.
Fig. 7 is example is measured in expression according to the frequency spectrum of the inclined optical fiber grating of embodiment 5 a curve.
Fig. 8 is the curve of expression according to the spectrometer example of the inclined optical fiber grating of embodiment 5.
Fig. 9 be expression according to the change of embodiment 5 curve of measurement result of transmission loss of the inclined optical fiber grating under the situation of optical fiber minister degree of parasitic light (stray light) decay usefulness.
Figure 10 is the structure of fiber grating is used in expression according to the light transmitting receiving module of embodiment 6 a key diagram.
Figure 11 is the curve of expression according to the spectrometer example of the inclined optical fiber grating of embodiment 6.
Figure 12 is the structure of fiber grating is used in expression according to the light transmitting receiving module of embodiment 7 a key diagram.
Figure 13 is the manufacture method of fiber grating is used in expression according to the light transmitting receiving module of embodiment 8 a key diagram.
Figure 14 is the key diagram based on the filter characteristic of diffusion light of the existing sending/receiving module of expression.
Figure 15 is the key diagram based on the filter characteristic of directional light of the existing sending/receiving module of expression.
Embodiment
＜embodiment 1 〉
Fig. 1 is the key diagram of expression according to the structure of the light transmitting receiving module of embodiment of the present invention 1.Light transmitting receiving module shown in Figure 1 is installed on entrant's sidelight line termination device.
Among Fig. 1, sending module 1 is as lower module, will be the light signal (light signal that comprises in the 1st wavestrip) of 1310nm wavelength as the converting electrical signal of upstream data. signals, and this optical wavelength is outputed to WDM wave filter 4.
Receiver module 3 is following the 2nd receiver modules, if from the light signal (light signal that 3rd wavestrip comprise) of WDM wave filter 5 receptions as the 1550nm wavelength of descending analog video signal, be electric signal with this converting optical signals then.
Among Fig. 1, the light signal that the 1st wavestrip that is sent by sending module 1 is shown is the light signal of 1310nm, the light signal of the 2nd wavestrip that is received by receiver module 2 is the light signal of 1490nm, the light signal of the 3rd wavestrip that is received by receiver module 3 is the example of the light signal of 1550nm, but this only is an example, and much less the 1st, the 2nd and the 3rd wavestrip also can be other wavestrips.
Optical fiber ferrule 6 is the parts that hold that are used for accommodating belt grating fibers 7, and among the figure, the right side that is arranged on WDM wave filter 5 is contiguous.
Grating belt optical fiber 7 is following optical fiber, transmission sees through the light signal of the wavelength 1310nm of WDM wave filter 5, and output to connector 8 sides, on the other hand, transmission is from the light signal of wavelength 1490nm, the 1550nm of connector 8 side incidents (light signal that the slave station side sends), and outputs to WDM wave filter 5 sides.This grating belt optical fiber 7 has following function, that is, stop the arrowband (the 1st wavestrip) comprise wavelength 1310nm, comprise the arrowband (the 2nd wavestrip) of wavelength 1490nm and comprise the function of the narrow band filter that the light signal of arrowband (the 3rd wavestrip) frequency band in addition of wavelength 1550nm sees through.
Below, the action according to the light transmitting receiving module of embodiment 1 is described.At first, illustrate that the light transmitting receiving module in entrant's sidelight line termination device sends to upstream data. signals the action of station sidelight line termination device.
When the electric signal that receives as upstream data. signals, sending module 1 is the light signal of 1310nm wavelength with this converting electrical signal, and this light signal is outputed to WDM wave filter 4.
When sending module 1 receives the light signal of wavelength 1310nm, WDM wave filter 4 makes the light signal of wavelength 1310nm see through WDM wave filter 5 sides.
Thus, incide optical fiber ferrule 6, the light signal of wavelength 1310nm is transmitted in grating belt optical fiber 7, and inject to single-mode optical fiber from connector 8 by light signal with wavelength 1310nm.
Secondly, the light transmitting receiving module slave station sidelight line termination device downlink data receiving/voice signal that entrant's sidelight line termination device is interior and the action of analog video signal be describeds.
Slave station sidelight line termination device send as the light signal of the wavelength 1490nm of downlink data/voice signal with as the light signal of the wavelength 1550nm of descending analog video signal, in single-mode optical fiber, transmit, and from connector 8 incidents.
Thus, the light signal of wavelength 1490nm, 1550nm transmits in grating belt optical fiber 7, injects to WDM wave filter 5 from optical fiber ferrule 6.
When optical fiber ferrule 6 receives the light signal of wavelength 1490nm, 1550nm, WDM wave filter 5 separates the light signal of wavelength 1490nm and the light signal of wavelength 1550nm, make the light signal of wavelength 1490nm see through WDM wave filter 4 sides, on the other hand, make the light signal of wavelength 1550nm reflex to receiver module 3 sides.
When WDM wave filter 5 receives the light signal of wavelength 1550nm, receiver module 3 is an electric signal with the converting optical signals of wavelength 1550nm, and output is as the descending analog video signal of electric signal.
When WDM wave filter 4 receives the light signal of wavelength 1490nm, receiver module 2 is an electric signal with the converting optical signals of wavelength 1490nm, and output is as the downlink data/voice signal of electric signal.
Here, when optical fiber was shone by ultraviolet ray, grating belt optical fiber 7 was the optical fiber that utilizes the photo-induced refractive index change of refractive index rising.
That is, when optical fiber was shone by ultraviolet ray, grating belt optical fiber 7 formed diffraction lattice in the core of optical fiber or clad, periodic variations in refractive index.
Thus, grating belt optical fiber 7 is owing to the specific optical wavelength reflection that only can make corresponding to this cycle, so as the optical-fiber type device with optical filter (narrow band filter) function.
In addition, grating belt optical fiber 7 is owing to directly forming diffraction lattice in non-destruction ground in optical fiber, so can low-costly make.In addition, owing to also can easily make changes in optical properties such as centre wavelength, frequency span, reflectivity, has the advantage that obtains low-loss, miniaturization, high reliability.
The grating belt optical fiber 7 that is installed in the light transmitting receiving module of Fig. 1 has the function of narrow band filter, promptly, the light signal of the arrowband that comprises wavelength 1310nm, the light signal of arrowband that comprises wavelength 1490nm and the light signal that comprises the arrowband of wavelength 1550nm are seen through, but make the attenuated optical signal of the frequency band beyond above-mentioned 3 arrowbands.
Therefore, there is no need as existing light transmitting receiving module at the internal configurations narrow band filter.Thus, owing to need not make optical wavelength be transformed to collimated light from diverging light, so there is no need as existing light transmitting receiving module, to dispose collimating optics equipment.
In addition, grating belt optical fiber 7 by the light signal that makes the arrowband that comprises wavelength 1310nm, comprise the arrowband of wavelength 1490nm and comprise the frequency band beyond the arrowband of wavelength 1550nm from the core energy dispersal in the optical fiber to clad, can guarantee the reflection loss amount.
Here, Fig. 2 is the key diagram of expression fiber grating characteristic.As can be seen from Figure 2, narrow band filter and collimating optics equipment be not set, in the GE-PON system of the guard band of wavestrip is set (λ 1-α), λ 1, (λ 1+ α), can avoiding the transmission of unwanted optical wavelength to receive.Rectangle part implication among Fig. 2 is a standard format.
From as can be known above, according to this embodiment 1, constitute and use grating belt optical fiber 7 as in the side of will arriving at a station through the optical signal transmission of the wavelength 1310nm of WDM wave filter 4,5, the optical signal transmission of wavelength 1490nm, the 1550nm that the slave station side is sent is to the optical fiber of WDM wave filter 5 sides, have preventions (making reflection) comprise wavelength 1310nm the arrowband, comprise the arrowband of wavelength 1490nm and comprise the narrow band filter function that the light signal of the arrowband frequency band in addition of wavelength 1550nm sees through.Therefore, narrow band filter and collimating optics equipment are not set, just can guarantee transmission quality, its result has realized the effect that miniaturization and component costs reduce.
＜embodiment 2 〉
Fig. 3 is the key diagram of expression according to the structure of the light transmitting receiving module of embodiment of the present invention 2.Among Fig. 3, with the identical identical or considerable part of symbolic representation of Fig. 1 of explanation in the embodiment 1, so suitably omit explanation.
Grating belt optical fiber ferrule 9 is that the grating department in the grating belt optical fiber 7 that holds with Fig. 1 divides the optical fiber ferrule of suitable part.
One end of optical fiber 10 is connected with grating belt optical fiber in being contained in grating belt optical fiber ferrule 9, transmission sees through the light signal of the wavelength 1310nm of WDM wave filter 5, and output to connector 8 sides, on the other hand, transmission is from the light signal of wavelength 1490nm, the 1550nm of connector 8 side incidents (light signal that the slave station side sends), and outputs to WDM wave filter 5 sides.
In above-mentioned embodiment 1, show the example of connecting band grating fibers 7 between optical fiber ferrule 6 and connector 8, and in the embodiment 2 along with change of refractive, make the thin rectangleization of grating length of this grating belt optical fiber 7, thus the grating department branch is contained in the optical fiber ferrule 6.Specific as follows.
The grating belt optical fiber ferrule 9 of Fig. 3 is conceived to, when refractive index variable quantity is made as n times, and can be with the grating length thin-long to 1/n
2, make grating be formed at the core of the optical fiber in the optical fiber ferrule.
Thus, owing to can cut down the zone that redundant optical fiber is handled, that is, owing to can shorten the length of optical fiber 10, so can realize the save spaceization of entrant's sidelight line termination device.In addition, by with the fiber lengths thin-long, can realize that direct material cost reduces.
Therefore, the light transmitting receiving module of embodiment 2 is compared than the light transmitting receiving module of embodiment 1, has further realized the effect that miniaturization and component costs reduce.
＜embodiment 3 〉
Fig. 4 is the key diagram of expression according to the structure of the light transmitting receiving module of embodiment of the present invention 3.Among Fig. 4, the symbolic representation identical or considerable part identical with Fig. 1 and Fig. 3 is so suitably omit explanation.
Grating belt connector 11 is that the grating department in the grating belt optical fiber 7 that holds with Fig. 1 divides the connector of suitable part.
In the light transmitting receiving module of embodiment 1, show connecting band grating fibers 7 between optical fiber ferrule 6 and connector 8, and in the embodiment 3 along with change of refractive, make the grating length thin-long of this grating belt optical fiber 7, thus, the grating department branch with grating belt optical fiber 7 is contained in the connector 8.Specific as follows.
The grating belt connector 11 of Fig. 4 is conceived to, when refractive index variable quantity is made as n times, and can be with the grating length thin-long to 1/n
2, make grating be formed at the core of the optical fiber in the connector 11, the grating part is set.
Thus, owing to can cut down the zone that redundant optical fiber is handled, so can realize the save spaceization of entrant's sidelight line termination device.In addition, by with the fiber lengths thin-long, can realize that direct material cost reduces.
Therefore, the light transmitting receiving module of embodiment 3 is compared with the light transmitting receiving module of embodiment 1, has further realized the effect that miniaturization and component costs reduce.
＜embodiment 4 〉
Fig. 5 is the key diagram of expression according to the structure of the light transmitting receiving module of embodiment of the present invention 4.Among Fig. 5, the identical or considerable part of the symbolic representation identical with Fig. 1 is so suitably omit explanation.
It is contiguous that grating belt socket 12 is arranged on the right side of WDM wave filter 5 among the figure, and is connected with an end of single-mode optical fiber, and have with the optical axis of optical module and adjust function and and the optical module parts of the bindiny mechanism of aerial lug.
The grating department that grating belt socket 12 holds in the grating belt optical fiber 7 with Fig. 1 divides suitable part.
In embodiment 1, show connecting band grating fibers 7 between optical fiber ferrule 6 and connector 8, and in the embodiment 4 along with change of refractive, make the grating length thin-long of this grating belt optical fiber 7, thus, grating belt optical fiber 7 is contained in the socket.Specific as follows.
The grating belt socket 12 of Fig. 5 is conceived to, when refractive index variable quantity is made as n times, and can be with the grating length thin-long to 1/n
2, make grating be formed at the core of the optical fiber in the socket.
Thus, owing to can cut down the zone that redundant optical fiber is handled, so can realize the save spaceization of entrant's sidelight line termination device.In addition, by with the fiber lengths thin-long, can realize that direct material cost reduces.
Therefore, the light transmitting receiving module of embodiment 4 is compared with the light transmitting receiving module of embodiment 1, has further realized the effect that miniaturization and component costs reduce.
＜embodiment 5 〉
Fig. 6 is the structure of fiber grating is used in expression according to the light transmitting receiving module of embodiment of the present invention 5 a key diagram.
As shown in Figure 6, shape ground, the center of circle covers core 13 clad 14 is set, and core 13 has inclined optical fiber grating portion 15 and parasitic light decay optical fiber portion 16.
In embodiment 5, use inclined optical fiber grating as wavelength filter.Below, the method for making of inclined optical fiber grating portion 15 at first is described.The fiber grating utilization is made the ultraviolet photoetching of optical fiber.As the optical fiber that uses, preferably, the type that on optical characteristics such as core diameter or numerical aperture, has interchangeability with the optical fiber that is connected to light transmitting receiving module from outside (connector 8 sides (with reference to Fig. 1) see through the light incident side of light).If non-interchangeability on the optics, then connecting through the joints of optical fibre etc. under the situation of light transmitting receiving module and external fiber, the generation junction loss becomes the reason of signal degradation.In the present embodiment, using interpolation Ge and B (boron) to improve the so-called light-sensitive optical fibre of exposure sensitivity, is optical fiber (by quartz glass clad and the core formation of adding Ge (germanium)) and do not use the quartz glass that uses in the optical communication.Particularly, use clad to be quartz glass equally, to add Ge and B, mode field (mode field) diameter, numerical aperture and clad diameter are made as optical fiber with the same standard of single-mode optical fiber of outside to core, the mode field diameter is about 10 μ m, numerical aperture is about 0.13, and the clad diameter is 125 μ m.
Before fiber grating exposure, in order to improve the exposure sensitivity, in high pressure hydrogen (100 air pressure) atmosphere gas, carry out the processing in 2 weeks after, irradiation Nd-YAG laser (output 200mW, wavelength 266nm) forms grating.The laser of exposure usefulness also can use excimer laser.The part of irradiating ultraviolet light is after the covering of removing optical fiber, and clad exposes, and exposes near the state of phase mask.
Phase mask is configured to, and be adjusted so that wavelength 1.55 μ m frequency bands become the mode cycle of bragg wavelength, and the perpendicular line of the length direction of the relative optical fiber of periodical configuration of mask tilts with angle θ (with reference to Fig. 6).θ be defined as greater than-90 °, less than 90 ° scope in.
In inclined optical fiber grating portion 15,, produce the transmission loss that is called the clad pattern than the short wavelength side of bragg wavelength.In uniform grating of cycle, the clad modal loss forms periodic comb shape spectral shape, but in make the linear modulation grating that the cycle changes in grating, spectral shape averages out, and becomes wide spectral shape.
For the optical characteristics of fiber grating is described, use the frequency spectrum of the inclined optical fiber grating portion 15 shown in Fig. 7 to measure routine curve.Fiber grating is using light-sensitive optical fibre, makes phase mask about 3.1 degree that tilt, and establishing grating length is 5mm, and exposing under the condition of the about 0.4nm of linear modulation amount obtains.Transmission loss and reflecting spectrum have been shown among Fig. 7.Bragg reflection is present among the wavelength 1556-1557nm, but because the angle of inclination is adjusted into the condition that Bragg reflection diminishes, so reflection strength becomes-the following little value of 30dB.Because reflection strength is enough little, so above-mentioned wavelength does not present structure in the transmission loss frequency spectrum.The loss that presents in the wavelength side shorter than 1553nm in the transmission loss frequency spectrum comes from above-mentioned clad pattern.Because the fiber grating linear modulation, so the frequency spectrum of comb shape structure averages out.Near the 1555nm loss is to come from from the frequency spectrum structure of basic communication mode to the reflection of high order LP11 pattern, is also referred to as the afterimage grating.In the optical fiber before the exposure, this mode propagation loss is big, also is not rendered as the frequency spectrum structure, but when exposing by grating, the mean refractive index of core uprises, and when propagation loss reduces, as shown in Figure 7, just increases as transmission loss.The LP11 pattern is because can decay under the fiber area that grating is not exposed, thus think that originally reflection strength is just little, but because the influence of the unevenness of grating etc. can produce residual reflection.Structure about the reflection strength-25dB that presents among the wavelength 1554-1555nm of Fig. 7 is just based on this residual reflection.
Owing to depending on the grating slope angle, the transmission loss of Bragg reflection intensity and clad pattern and afterimage grating changes, so in order to obtain desired characteristics, the mask angle of inclination when being necessary to adjust exposure.Especially, Bragg reflection has the character that depends on the grating slope angle sensitively.Fiber grating length is long more, and then the variations in refractive index based on exposure is just big more, and it is big that transmission loss becomes, but by the optic fibre characteristic of variations in refractive index because of using that exposure produces, has been determined the upper limit.Therefore, for the transmission loss that obtains expecting, at first the intrinsic suitable variations in refractive index of optical fiber of hypothesis use is followed the grating length of considering only to obtain necessary transmission loss, exposes.
In order to use in light transmitting receiving module at GE-PON, characteristic as wavelength filter, be necessary to be, among the use wavelength X B of the use wavelength X A of wavelength 1310nm frequency band and 1490nm frequency band, the use wavelength X C of 1550nm frequency band, transmission loss is little, use near the middle transmission loss of the guard band (for example wavestrip λ C-α) of wavelength big, be low reflection under these wavestrips.
It is that the angle of inclination of 50mm, grating is 4.5 degree, is 2 * 10 based on the variations in refractive index of exposure that the curve of Fig. 8 shows the hypothesis grating length
-3The time the seeing through/reflecting spectrum (result of calculation) of fiber grating.
Wavelength width (for example 1.5nm) in order to realize desired transmission loss is made as the linear modulation grating.If the linear modulation amount as the difference of the maximal value of the bragg wavelength of fiber grating and minimum value is 2.7nm.In addition, in order to reduce reflection, suppose the toe (apodized) of cutting that refractive index variable quantity slowly diminishes to be handled at the both ends of grating.
Can confirm that from Fig. 8 the transmission loss under the use wavelength X C of 1552nm is little, be 40dB above (with reference to Fig. 8 (a)) than the transmission loss under the guard band wavestrip (λ C-α) of using the short wavelength side of wavelength, reflection strength little (with reference to Fig. 8 (b)), required standard satisfies on calculating as can be known.Grating slope in the fiber cores is about 1.45 times of mask angle of inclination, so the mask angle of inclination is made as 3.1 degree when making.But, the fiber grating of measuring actual trial-production see through frequency spectrum the time, distinguish the following problem that produced, promptly produce the parasitic light of propagating in the clad part, the problem that transmission loss diminishes at grating department.At this problem, discovery utilizes the clad propagates light owing to the loss on the ferrule interface decays, by end parasitic light decay optical fiber portion is set at fiber grating, can avoid the minimizing of transmission loss, in order to obtain the transmission loss more than the 40dB, as long as in mensuration, confirm to be provided with parasitic light decay optical fiber portion.Fig. 9 represents to have measured the result's of transmission loss curve to after the length of same inclined optical fiber grating portion's 15 change parasitic lights decay with optical fiber portion 16.As can be seen from Figure 9, in order to obtain the transmission loss more than the 40dB, as long as the above parasitic light decay optical fiber portion 16 of 16cm is set.
Therefore, in order to use in light transmitting receiving module, as long as the parasitic light decay more than the subsidiary length 16cm is with the structure of optical fiber portion 16 in above-mentioned inclined optical fiber grating portion 15 at GE-PON.
Change the trial-production at angle of inclination with regard to reflection characteristic, confirmed that reflection strength is minimum near 3.1 degree.The angle of inclination is adjusted into the best,, can obtains good low reflection characteristic by the uniform exposure grating.
By the fiber grating that illustrates in the above present embodiment, obtain GE-PON with wavelength characteristic essential in the wavelength region may of using in the light transmitting receiving module, so can realize the action of the example of explanation in embodiment 1 and the embodiment 3, can realize the save spaceization of entrant's sidelight line termination device.
＜embodiment 6 〉
Figure 10 is the structure of fiber grating is used in expression according to the light transmitting receiving module of embodiment of the present invention 6 a key diagram.
As shown in figure 10, in the present embodiment, as fiber grating, use to link by linking with inclined optical fiber grating 17a of portion (the 1st kind of grating belt optical fiber group) and the structure that links two grating departments that constitute with the non-inclined optical fiber grating 17b of portion (the 2nd kind of grating belt optical fiber group).Identical or the considerable part of the symbolic representation identical with Fig. 6 is so suitably omit explanation.
Use the light-sensitive optical fibre identical in the optical fiber with the situation of embodiment 5.Below, the characteristic of each grating is described.
Linking with the 17a of inclined optical fiber grating portion making becomes the angle of inclination that Bragg reflection diminishes, and has based on the transmission loss more than the 12.5dB of clad pattern.In addition, binding is produced on the non-inclined optical fiber grating 17b of portion and links the position of using the inclined optical fiber grating 17a of portion under the cycle that produces Bragg reflection under the above-mentioned clad modal loss wavelength of using the inclined optical fiber grating 17a of portion near binding.Finally, link with the inclined optical fiber grating 17a of portion, link with non-inclined optical fiber grating 17b of portion and parasitic light decay and make by this sequence interlock of optical fiber portion 16.Link with the 17a of inclined optical fiber grating portion and become the side that is connected with outside (connector 8 sides (with reference to Fig. 1)).Each grating both can expose respectively, also can use the phase mask that forms two kinds of corresponding patterns to unify exposure, can reduce cost but unification exposes, so preferably unified exposure.
Binding has based on the big wavestrip of the reflection strength of Bragg reflection with the non-inclined optical fiber grating 17b of portion, and its centre wavelength is bragg wavelength.By making the enough big wavestrip of transmission loss that links with the 17a of inclined optical fiber grating portion comprise the reflection wavestrip of binding, can reduce the binding seen from outer side intensity with the Bragg reflection of the non-inclined optical fiber grating 17b of portion with the non-inclined optical fiber grating 17b of portion.Comprise the little wavelength of transmission loss that links with the inclined optical fiber grating 17a of portion in the Bragg reflection wavestrip with the non-inclined optical fiber grating 17b of portion if link, then the reflection strength of seeing from outer side under this wavelength can become big.
As mentioned above, under the state of the binding that reduces to see with the intensity of the Bragg reflection of the non-inclined optical fiber grating 17b of portion from outer side, because the transmission loss of whole fiber grating becomes big especially in the Bragg reflection wavestrip that links with the non-inclined optical fiber grating 17b of portion, so, stop wavelength coverage to be contained in the wavestrip of above-mentioned Prague as long as see through as the wavelength filter that uses in the light transmitting receiving module.In addition, seeing through under the wide situation of prevention wavelength coverage,, can enlarge wavelength coverage by making the linearity of raster modulation.
Relativeness as wavelength location, because the transmission loss based on the clad pattern produces under than the short wavelength of Bragg reflection, stop wavelength coverage to be made as so will link seeing through of comprising in the transmission loss wavelength band with the non-inclined optical fiber grating 17b of portion than linking with the short wavelength side of the bragg wavelength frequency band of the inclined optical fiber grating 17a of portion based on Bragg reflection, in the long wavelength side of bragg wavelength frequency band of using the inclined optical fiber grating 17a of portion than binding, do not produce Bragg reflection, thus, as mentioned above, can reduce the binding seen from outer side intensity with the Bragg reflection of the non-inclined optical fiber grating 17b of portion.Because the Bragg reflection intensity that links with the 17a of inclined optical fiber grating portion diminishes by adjusting the angle of inclination, so can be in the long little wavelength filter characteristic of reflection strength that obtains of all-wave.
When establish expectation see through to stop in the wavelength coverage, link when being respectively L1 (dB), L2 (dB) with the light transmission loss of the non-oblique raster of the non-inclined optical fiber grating 17b of portion with the light transmission loss of the oblique raster of the 17a of inclined optical fiber grating portion and binding, satisfy " L1 ≧ 12.5, L1+L2 ≧ 40 " (the 1st condition).
In addition, be respectively R1 (dB), R2 (dB) when establishing the above-mentioned light reflectivity that sees through the oblique raster in the bragg wavelength frequency band that stops wavelength coverage and oblique raster, when being R0 (dB), be necessary to satisfy following formula (1) (the 2nd condition) through the reflectivity that stops the non-oblique raster in the wavelength coverage.
［ formula 1 ］
In addition, can adjust the angle of inclination, cycle and the parasitic light decay that link with the oblique raster among the inclined optical fiber grating 17a of the portion fiber lengths of optical fiber portion 16, with when satisfying the above-mentioned the 1st and the 2nd condition, make that above-mentioned see through to stop in the wavelength coverage minimum value as the light transmission loss of optical filter integral body be more than the 40dB, and spreading all over the long frequency band of all-wave, light reflectivity is-below the 25dB.
For example, illustrated in the curve of Figure 11 that to establish the length that links with the 17a of inclined optical fiber grating portion be 45mm, link length with the non-inclined optical fiber grating 17b of portion be 10mm, phase mask angle of inclination be 3.1 spend, the linear modulation amount is that 2.7nm, refractive index variable quantity are 1.2 * 10
-3, the optical characteristics result of calculation of the binding fiber grating when cutting toe and handling arranged.Above-mentioned standard (condition) is all satisfied in transmission loss (with reference to Figure 11 (a)), reflection (with reference to Figure 11 (b)) as can be known.Cut toe and handle and to be made as this shape of superelevation 6 times, but also 2 times or 4 these shapes of superelevation.
Among Figure 11 (a), at the 1550nm frequency band, the big transmission loss about wavelength width 2nm more than the discovery-40dB, but this is as mentioned above, based on the Bragg reflection that links with the non-inclined optical fiber grating 17b of portion.On the other hand, the wide transmission loss from this wavestrip to short wavelength side is based on the transmission loss that links with the clad pattern of the inclined optical fiber grating 17a of portion as can be known, and the relativeness of the wavelength location of two gratings as mentioned above.In addition, in two kinds of zones of reflections of the 1550nm frequency band of seeing among Figure 11 (b), the binding of short wavelength side reduces by the transmission loss of binding with the clad pattern of the 17a of inclined optical fiber grating portion with the Bragg reflection of the non-inclined optical fiber grating 17b of portion.Long wavelength side be the Bragg reflection intensity that links with the inclined optical fiber grating 17a of portion, reduce by adjusting the angle of inclination.
The situation of a kind of inclined optical fiber grating of explanation is compared in the fiber grating of this binding structure and the embodiment 5, for identical refractive index variable quantity, obtains high transmission loss under short fiber lengths, is easy to effect so have to make to become.In addition, owing to can increase the linear modulation amount of the per unit length of oblique raster, has the effect of the low reflection characteristic of easy acquisition.
By the fiber grating that illustrates in the above present embodiment, acquisition is essential wavelength characteristic in the wavelength region may that GE-PON uses in light transmitting receiving module, so can realize the action of the example of explanation in embodiment 1 and the embodiment 3, can realize the save spaceization of entrant's sidelight line termination device.
＜embodiment 7 〉
Figure 12 is the structure of fiber grating is used in expression according to the light transmitting receiving module of embodiment of the present invention 7 a key diagram.
As shown in figure 12, in the present embodiment, as fiber grating, use will link with the 1st 18a of oblique raster portion and link the structure that links with the non-inclined optical fiber grating 17b of portion (the 2nd kind of grating belt optical fiber group) with the 2nd 18b of oblique raster portion (the 1st kind of grating belt optical fiber group) and binding.Therefore, oblique raster portion presents the structure that links two kinds of 18a of oblique raster portion, 18b.The symbolic representation identical or considerable part identical with Fig. 6 or Figure 10 is so suitably omit explanation.
Use the identical light-sensitive optical fibre of situation in the optical fiber with embodiment 5 and embodiment 6.Below, the characteristic of each grating is described.
The angle of inclination that diminishes with Bragg reflection in the oblique raster portion makes and links with the 1st 18a of oblique raster portion (the 1st (inclination) grating), also makes with identical angle of inclination to link with the 2nd 18b of oblique raster portion (the 2nd (inclination) grating).In the 1st grating and the 2nd grating, under the linear modulation amount of same period and identical size, the transmission loss wavelength overlaps, but the 1st grating reduces FBG (Fiber Bragg Grating) length, and promptly the linear modulation quantitative change of per unit length is big.Thus, can make the 1st grating reflection rate become little than the 2nd grating reflection rate.
The same with the situation of embodiment 6, make to link and decay with optical fiber portion 16 with non-inclined optical fiber grating 17b of portion and parasitic light.Link be produced on oblique raster with the non-inclined optical fiber grating 17b of portion (non-oblique raster) above-mentioned clad modal loss wavelength down under cycle of generation Bragg reflection near the position of oblique raster 18b.Finally, link with the 1st 18a of oblique raster portion, link, link with non-inclined optical fiber grating 17b of portion and parasitic light decay and make by this sequence interlock of optical fiber portion 16 with the 2nd 18b of oblique raster portion.Link with the 1st 18a of oblique raster portion and become and the outside side that is connected.Each grating both can expose respectively, also can use the phase mask that forms three kinds of corresponding patterns to unify exposure, can reduce cost but unification exposes, so preferably unified exposure.
When the light transmission loss that see through to stop light transmission loss in the wavelength coverage, the light transmission loss of above-mentioned the 1st oblique raster, above-mentioned the 2nd oblique raster and above-mentioned non-oblique raster of establishing expectation is respectively L11 (dB), L21 (dB), L2 (dB), be necessary to satisfy " L11 ≧ 2.5; L11+L21 ≧ 12.5, L2 ≧ 15 " (the 3rd condition).
Light reflectivity in establishing the described bragg wavelength frequency band that see through to stop wavelength coverage and above-mentioned the 1st oblique raster, above-mentioned the 1st oblique raster is respectively R11 (dB), R12 (dB), when being respectively R21 (dB), R22 (dB), be necessary to satisfy following formula (2) and formula (3) (the 4th condition) based on light reflectivity in the bragg wavelength frequency band of the transmission loss wavelength band of the Bragg reflection of above-mentioned non-oblique raster and the above-mentioned the 1st and the 2nd oblique raster, above-mentioned the 2nd oblique raster.
［ formula 2 ］
［ formula 3 ］
And, the angle of inclination of adjustable lay the grain grid, cycle and parasitic light decay fiber lengths, with when satisfying the above-mentioned the 3rd and the 4th condition, make that above-mentioned see through to stop in the wavelength coverage minimum value as the light transmission loss of optical filter integral body be more than the 40dB, and spreading all over the long frequency band of all-wave, light reflectivity is-below the 25dB.
For example, be that 10mm, binding are that 35mm, binding are that 10mm, phase mask angle of inclination are that 3.1 degree, linear modulation amount are that 2.7nm, refractive index variable quantity are 1.2 * 10 with the length of the non-inclined optical fiber grating 17b of portion with the length of the 2nd 18b of oblique raster portion if establish the length that links with the 1st 18a of oblique raster portion
-3, cut toe and handle identically with the situation of embodiment 6, then obtain transmission loss, reflect the characteristic that all satisfies above-mentioned standard (condition).
The situation of two kinds of inclined optical fiber gratings of explanation is compared the effect that has the low reflection characteristic of easy acquisition and make easily in the fiber grating of this binding structure and the embodiment 6.This be because, when considering the reflection characteristic of wavelength filter integral body, because above-mentioned the 1st oblique raster can increase the linear modulation amount of oblique raster per unit length,, be lowered based on the contribution of the reflection of above-mentioned the 2nd oblique raster transmission loss by above-mentioned the 1st oblique raster so can hang down reflection.
See through stoping near the wavelength coverage, as the grating integral body of seeing from outer side, owing to be low reflection characteristic, so be necessary to comprise more reflected wavelength range by the oblique raster of private side near the transmission loss wavelength coverage of the oblique raster of outer side.In addition, the linear modulation amount of oblique raster per unit length is big more, the grating of the low reflection of then easy more acquisition, but transmission loss intensity also reduces.Therefore, for for the oblique raster of outer side, adjust whole linear modulation amounts, so that the transmission loss wavelength coverage becomes more than the reflected wavelength range of the oblique raster that more leans on private side, and the linear modulation amount and the fiber grating length of adjustment per unit length, to have the transmission loss intensity more than the reflection reduction outstanding effect 1dB, also adjust wavelength location, so that the transmission loss wavelength coverage comprises the reflected wavelength range of more leaning on the oblique raster of private side, thus, as the grating integral body of seeing from outer side, can obtain low reflection characteristic.
In addition, for the reflection under the transmission loss wavelength of the oblique raster that reduces the most external side, for example, as described below.As shown in Figure 7, because the transmission loss wavelength is identical wavelength with reflection wavelength substantially, so, be identical wavelength location with Prague wavestrip of the 2nd oblique raster for example if establish Prague wavestrip of above-mentioned the 1st oblique raster, more than whole linear modulation amounts of whole linear modulation amounts with the 1st oblique raster as the 2nd oblique raster, Prague wavestrip of the 1st oblique raster comprises Prague wavestrip of the 2nd oblique raster, then the transmission loss wavestrip of the 1st oblique raster can comprise the reflection wavestrip of the 2nd oblique raster, as the grating integral body of seeing from outer side, can obtain low reflection characteristic.
The multiplexed of this oblique raster has if link the effect that further increases the low reflection characteristic of the then easier acquisition of multiplexed rate from 2.At this moment, as long as the cycle is identical in each oblique raster, near the outside oblique raster that connects side, the linear modulation amount of per unit length is big more, all the linear modulation amounts identical or on get final product.
By the fiber grating that illustrates in the above present embodiment, can obtain essential wavelength characteristic in the wavelength region may that GE-PON uses in light transmitting receiving module, so can realize the action of the example of explanation in embodiment 1 and the embodiment 3, can realize the save spaceization of entrant's sidelight line termination device.
＜embodiment 8 〉
Figure 13 is the key diagram of the method for making of the fiber grating that uses in the light transmitting receiving module of expression according to embodiment of the present invention 8.
Fiber grating is made by ultraviolet photoetching, but owing to cause light refraction when the ultraviolet light by phase mask sees through the optical fibre packages clad surface, so the angle of inclination of the structure of the interior actual exposure of optical fiber becomes about 1.45 times of angle of inclination of phase mask.In addition, because of optically focused effect, there is the structure of the grating uneven possibility that becomes based on the barrel surface of clad.
In the present embodiment, shown in Figure 13 (a), on dielectric plate 19, be full of optical fiber (core 13, clad 14) on every side, expose through phase mask 20 with irradiating ultraviolet light 21 by exposure with ultraviolet light permeability liquid 22.
For example, under the situation that makes water as ultraviolet light permeability liquid 22, because the refractive index of water is near the refractive index of optical fibre packages coating, so reduce the refraction effect on clad 14 surfaces.Its result, the angle of inclination of the structure of actual exposure converges to about 1.1 times of angle of inclination of phase mask 20 in the optical fiber.The adjustment precision at the angle of inclination of phase mask 20 is determined by mechanical tolerance, but when making fiber grating with the angle of inclination of expecting as if consideration, then the ratio at the angle of inclination of the structure of actual exposure and the angle of inclination of phase mask 20 hour in the optical fiber can improve the precision at the angle of inclination of the structure of actual exposure in the optical fiber.At this moment, angle precision can improve about 30%.In order to obtain to hang down reflection characteristic, be necessary the angle of inclination is adjusted into the size of expectation, if angular misalignment, then Bragg reflection intensity can increase, so have if improve the then easy effect of manufacturing change of low reflection characteristic of angle precision.
Same angle precision improves effect shown in Figure 13 (b), also can optical fiber (core 13, clad 14) be set by among the 23g of ditch portion that is provided with in the dielectric plate 23 of band ditch, and exposing through phase mask 20 with irradiating ultraviolet light 21 by exposing obtains.
For example, ditch is set in quartz glass plate, is used as under the situation with the dielectric plate 23 of ditch and since with the refractive index of optical fibre packages coating do not have do not have poor, so cover surface does not produce ray refraction.Its result, the angle of inclination of the structure of actual exposure is identical with the angle of inclination of phase mask in the optical fiber, and the angle precision of grating can further improve.The 23g of ditch portion that is arranged in the dielectric plate 23 of being with ditch needn't be in full accord with the shape of optical fibre packages coating, even if for example easy V-shape ditch that forms also can obtain same effect.
By the fiber grating that illustrates in the above present embodiment, can obtain essential wavelength characteristic in the wavelength region may that GE-PON uses in light transmitting receiving module, so can realize the action of the example of explanation in embodiment 1 and the embodiment 3, can realize the save spaceization of entrant's sidelight line termination device.
Though describe the present invention in detail, above-mentioned explanation only is an example in all respects, the invention is not restricted to this.Being interpreted as not the countless variation of example can not depart from the scope of the present invention and obtain.
Claims (13)
1. light transmitting receiving module is characterized in that possessing:
Sending module (1) sends the light signal of the 1st wavestrip;
The 1st receiver module (2) receives the light signal of 2nd wavestrip different with described the 1st wavestrip;
The 2nd receiver module (3) receives the light signal of 3rd wavestrip different with the described the 1st and the 2nd wavestrip;
Wavelength separation multiplex Multiplexing Unit (4,5), the light signal of the 1st wavestrip of sending from described sending module is seen through, and separate the described the 2nd and the light signal of the 3rd wavestrip, when the light signal with described the 2nd wavestrip outputs to described the 1st receiver module, the light signal of described the 3rd wavestrip is outputed to described the 2nd receiver module; With
Grating belt optical fiber (7), when the optical signal transmission of the 1st wavestrip that will see through by described Wavelength separation multiplex Multiplexing Unit is arrived at a station side, the optical signal transmission of the 2nd and the 3rd wavestrip that will send from described station side is to described Wavelength separation multiplex Multiplexing Unit, and stop the seeing through of light signal of the frequency band beyond described the 1st, the 2nd and the 3rd wavestrip, have the function of narrow band filter.
2. light transmitting receiving module according to claim 1 is characterized in that:
Described Wavelength separation multiplex Multiplexing Unit is made of the 1st Wavelength separation multiplex multiplex filter (4) and the 2nd Wavelength separation multiplex multiplex filter (5),
Described the 1st Wavelength separation multiplex multiplex filter (4) sees through the light signal of described the 1st wavestrip of sending from described sending module, and makes the light signal of described the 2nd wavestrip by described grating belt Optical Fiber Transmission reflex to described the 1st receiver module side,
Described the 2nd Wavelength separation multiplex multiplex filter (5) sees through the light signal of the light signal that sees through described the 1st wavestrip that described the 1st Wavelength separation multiplex multiplex filter comes and described the 2nd wavestrip by described grating belt Optical Fiber Transmission, and makes the light signal of described the 3rd wavestrip by described grating belt Optical Fiber Transmission reflex to described the 2nd receiver module side.
3. light transmitting receiving module according to claim 1 is characterized in that:
Described grating belt optical fiber passes through the light signal of the frequency band of core beyond described the 1st, the 2nd and the 3rd wavestrip of clad energy dispersal internally, guarantees the reflection loss amount.
4. according to any described light transmitting receiving module among the claim 1-3, it is characterized in that:
Between described Wavelength separation multiplex Multiplexing Unit and described grating belt optical fiber, optical fiber ferrule (9) is set, the connector (8) of one end of the end that connects described grating belt optical fiber and single-mode optical fiber is set simultaneously, pass through change of refractive, grating grating length thin-long partly with described grating belt optical fiber is contained in described grating department branch in the described optical fiber ferrule.
5. according to any described light transmitting receiving module among the claim 1-3, it is characterized in that:
Between described Wavelength separation multiplex Multiplexing Unit and described grating belt optical fiber, described optical fiber ferrule (6) is set, the connector (11) of one end of the end that connects described grating belt optical fiber and single-mode optical fiber is set simultaneously, according to change of refractive, grating grating length thin-long partly with described grating belt optical fiber is contained in described grating department branch in the described connector.
6. according to any described light transmitting receiving module among the claim 1-3, it is characterized in that:
Also possess: be arranged on the socket (12) of described station side,
According to change of refractive,, the grating department branch of described grating belt optical fiber is contained in the described socket the grating length thin-long of described grating belt optical fiber.
7. according to any described light transmitting receiving module among the claim 1-3, it is characterized in that:
The light signal of the 1st wavestrip that is sent by described sending module is the light signal of 1310nm, the light signal of the 2nd wavestrip that is received by described the 1st receiver module is the light signal of 1490nm, and the light signal of the 3rd wavestrip that is received by described the 2nd receiver module is the light signal of 1550nm.
8. according to any described light transmitting receiving module among the claim 1-3, it is characterized in that:
Described grating belt optical fiber is the grating belt optical fiber portion (15) and the optical fiber of the parasitic light decay that is used for making the parasitic light decay of propagating at the clad of optical fiber with optical fiber portion (16) that optics connects the grating with the direct of travel inclination that sees through light relatively.
9. according to any described light transmitting receiving module among the claim 1-3, it is characterized in that:
As described grating belt optical fiber, optics connects at least two grating belt optical fiber portions (17a, 17b, 18a, 18b) and the parasitic light decay optical fiber portion (16) that is used for making the parasitic light decay of propagating at the clad of optical fiber,
At least more than one of described at least two grating belt optical fiber portions, the 1st kind of grating belt optical fiber group (17a, 18a, 18b) as the direct of travel that sees through light relatively tilts is configured in the light incident side through light,
And the decay of described parasitic light is formed at emitting side through light with optical fiber portion,
And, other of described at least two grating belt optical fiber portions at least one, as second kind of grating belt optical fiber group (17b), form the angle that sees through the basic quadrature of direct of travel of light relatively, be configured in the decay of described the 1st kind of grating belt optical fiber group and described parasitic light with between the optical fiber portion.
10. light transmitting receiving module according to claim 9 is characterized in that:
Described the 1st kind of grating belt optical fiber group is made of the linear modulation diffraction lattice,
And, seeing through of comprising in will the transmission loss wavelength band based on the 2nd kind of grating belt optical fiber group's Bragg reflection stops wavelength coverage, be made as the wavelength side shorter, do not produce Bragg reflection in the wavelength side longer than the 1st kind of grating belt optical fiber group's bragg wavelength frequency band than the 1st kind of grating belt optical fiber group's bragg wavelength frequency band.
11. light transmitting receiving module according to claim 10 is characterized in that:
Described the 1st kind of grating belt optical fiber group is made of the linear modulation diffraction lattice (18a, 18b) that at least two above optics connect,
Among the 1st kind of grating belt optical fiber group, be configured in through the linear modulation amount of the per unit length of the diffraction lattice of the initial light incident side of light bigger than the linear modulation amount of the per unit length of other grating belt optical fiber,
And, be configured in the reflection wavelength frequency band that comprises other grating belt optical fiber through the transmission loss wavelength band of the grating belt optical fiber of the initial light incident side of light.
12. light transmitting receiving module according to claim 10 is characterized in that:
When the seeing through the light transmission loss that stops light transmission loss in the wavelength coverage, described the 1st kind of grating belt optical fiber group and described the 2nd kind of grating belt optical fiber group and be respectively L1 (dB), L2 (dB) of the expectation that comprises in the transmission loss wavelength band of establishing based on described the 2nd kind of grating belt optical fiber group's Bragg reflection, satisfy L1 ≧ 12.5, L1+L2 ≧ 40
Be respectively R1 (dB), R2 (dB) when establishing the described light reflectivity that sees through the 1st kind of grating belt optical fiber group in the bragg wavelength frequency band that stops wavelength coverage and the 1st kind of grating belt optical fiber group, when the described reflectivity that sees through the 2nd kind of grating belt optical fiber group in the prevention wavelength coverage is R0 (dB), satisfy following formula 1
［ formula 1 ］
And then, adjust the fiber lengths of angle of inclination, cycle and the parasitic light decay usefulness of grating, so that described see through to stop in the wavelength coverage minimum value as the light transmission loss of optical filter integral body be more than the 40dB, and spread all over whole wavelength bands, light reflectivity becomes-below the 25dB.
13. light transmitting receiving module according to claim 10 is characterized in that:
When establish described see through to stop in the wavelength coverage, be configured among described the 1st kind of grating belt optical fiber group removed the light transmission loss that is configured in through the grating belt optical fiber behind the grating belt optical fiber of the initial light incident side of light among light transmission loss through the diffraction lattice of the initial light incident side of light, the 1st kind of grating belt optical fiber group, when being respectively L11 (dB), L21 (dB), L2 (dB) with described the 2nd kind of grating belt optical fiber group's light transmission loss, satisfy L11 ≧ 2.5, L11+L21 ≧ 12.5, L2 ≧ 15
Light reflectivity in establishing the described bragg wavelength frequency band that see through to stop wavelength coverage and the 1st kind of grating belt optical fiber group, that be configured among the 1st kind of grating belt optical fiber group through the diffraction lattice of the initial light incident side of light is respectively R11 (dB), R12 (dB),
Based in the transmission loss wavelength band of the 2nd kind of grating belt optical fiber group's Bragg reflection and the 1st kind of grating belt optical fiber group's the bragg wavelength frequency band, when having removed the light reflectivity that is configured in through the grating belt optical fiber behind the grating belt optical fiber of the initial light incident side of light among the 1st kind of grating belt optical fiber group and being respectively R21 (dB), R22 (dB), satisfy following formula 2, formula 3
［ formula 2 ］
［ formula 3 ］
And then, adjust the fiber lengths of angle of inclination, cycle, linear modulation amount and the parasitic light decay usefulness of grating, so that described see through to stop in the wavelength coverage minimum value as the light transmission loss of optical filter integral body be more than the 40dB, and all the light reflectivity of wavelength bands become-below the 25dB.
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|---|---|---|---|
| PCT/JP2009/050226 WO2010079611A1 (en) | 2009-01-09 | 2009-01-09 | Optical transmission/reception module |
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| CN102177455B CN102177455B (en) | 2015-08-12 |
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| JP (1) | JP5279847B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104808299A (en) * | 2015-05-08 | 2015-07-29 | 福州宏旭科技有限公司 | Multi-wavelength component for fiber optic communication |
| CN107424246A (en) * | 2017-04-11 | 2017-12-01 | 京东方科技集团股份有限公司 | Visible light communication password tripper and method |
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| JP3591932B2 (en) * | 1995-08-28 | 2004-11-24 | 住友電気工業株式会社 | Semiconductor light receiving element |
| WO1999057594A1 (en) * | 1998-04-30 | 1999-11-11 | Infineon Technologies Ag | Bidirectional optical module for multichannel utilization |
| CN1200290C (en) * | 2003-05-30 | 2005-05-04 | 中国科学院上海光学精密机械研究所 | Bandwidth-adjustable bevel fiber grating and manufacturing method thereof |
| JP2004361502A (en) * | 2003-06-02 | 2004-12-24 | Sumitomo Electric Ind Ltd | Optical transmission reception module |
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2009
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104808299A (en) * | 2015-05-08 | 2015-07-29 | 福州宏旭科技有限公司 | Multi-wavelength component for fiber optic communication |
| CN107424246A (en) * | 2017-04-11 | 2017-12-01 | 京东方科技集团股份有限公司 | Visible light communication password tripper and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102177455B (en) | 2015-08-12 |
| JPWO2010079611A1 (en) | 2012-06-21 |
| WO2010079611A1 (en) | 2010-07-15 |
| TWI402550B (en) | 2013-07-21 |
| JP5279847B2 (en) | 2013-09-04 |
| TW201027154A (en) | 2010-07-16 |
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