CN101251628A - Reconstructing light top and bottom path multiplexer based on two-dimension photon crystal - Google Patents

Abstract

The invention relates to a reconfigurable optical add-drop multiplexer based on a two-dimensional photonic crystal, comprising an upper end waveguide, a lower end waveguide, an upward road waveguide, a downward road waveguide, and a bend waveguide connecting the upward road waveguide and the downward road waveguide, wherein the upper end waveguide, the upward road waveguide and the downward road waveguide are respectively connected through an upward road micro-cavity and a downward road micro-cavity; a wavelength selective reflection micro-cavity is positioned between the upward road micro-cavity and the downward road micro-cavity; resonance frequencies of the three micro-cavities are the same; a ratio of Q factors of the upward road micro-cavity and the downward road micro-cavity and distances between the upward road micro-cavity and corresponding wavelength selective micro-cavity thereof and between the downward road micro-cavity and corresponding wavelength selective micro-cavity thereof meet a certain phase relationship towards the direction of the upper end waveguide, thereby implementing a complete translation of energy among the upper end waveguide, the upward road waveguide and the downward road waveguide; an add-drop multiplexer is formed together by three micro-cavities, the upper end waveguide, the upward road micro-cavity and the downward road micro-cavity, and the bend waveguide and the lower end waveguide are in a parallel placement at a short range to form a 2 multiplied by 2 directional coupling optical switch which is divided into a central coupling area, a decoupling area and an intermediate transitional chirp area, and radiuses of a dielectric cylinder close to the waveguides in the chirp area are gradually changed. The reconfigurable optical add-drop multiplexer of the invention has the advantages of small size and high integration.

Description

Reconstructing light top and bottom path multiplexer based on 2 D photon crystal

Technical field

The present invention relates to a kind of reconstructing light top and bottom path multiplexer, be applicable to optical fiber telecommunications system and loop network based on 2 D photon crystal.

Background technology

Data business volume causes optical-fiber network need go to increase the transmission capacity of network itself rapidly in the explosive increase of optical network node at present.Wavelength-division multiplex (WDM) technology can effectively utilize bandwidth of an optical fiber to realize high capacity, long-distance optical fiber communication, can increase number of services in user allocation system, is extensive use of in optical fiber telecommunications system.Light top and bottom path multiplexer (OADM) allows wavelength signals road about the optical network node quilt, is the Primary Component that makes up wdm optical communication system.In these OADM, reconfigurable light top and bottom path multiplexer (ROADM) can dispose wavelength channel and carry out dynamic wavelength route, is the requisite device of wdm system.Yet the size of utilizing the ROADM that dull and stereotyped loop of traditional silicon or optical fiber obtains is all in a centimetre magnitude.In the development of optical network in future, in order to make full use of most valuable bandwidth resources, it is more and more narrow that wavelength channel becomes at interval, and it is more and more that the number of channel becomes.This just requires the size of ROADM not only enough little, and will be easy to integrated.On the other hand, the research of photonic crystal has become one of focus of integrated optics research at present.This is that as photonic band gap effects, based on this characteristic, many optic communication devices may design and make based on photonic crystal because photonic crystal has a lot of superior characteristic, and they have the not available advantageous characteristic of traditional devices, and size is little and be easy to integrated.Therefore, design and development more small based on 2 D photon crystal, size, be easy to the important development direction that integrated ROADM is following wdm optical communication system.

Based on 2 D photon crystal set out on a journey or down in the path multiplexer, four port systems are promptly placed two photon crystal micro cavities in the middle of two parallel photonic crystal waveguide structures, be a kind of scheme of the comparative maturity of research at present.But the resonance design that this system requirements is comparatively harsh and complicated, promptly two microcavity patterns between two waveguides are wanted complete degeneracy, and this may bring very big difficulty to element manufacturing.Four port systems also have a shortcoming from structure, and the road is integrated up and down to be difficult for carrying out large-scale multi-wavelength exactly.In one three other port system, for obtaining the high efficient of road up and down, main waveguide end is upward stifled so that obtain 100% reflection feedback by crystalline network.But in the light signal of reflection, except the wavelength light signal that will descend the road enters down the waveguide of road, the light of other all wavelengths all will be reflected to the incident end.If using in large-scale integrated optical circuit, this device will bring serious signal to disturb to total system.And in this design, in order to satisfy the respective phase condition, the selection of distance is with descending the road wavelength to change, so can not guarantee same road at present on any multi-wavelength passage between reflecting surface and the waveguide of following road.Therefore based on 2 D photon crystal, studying novel high-level efficiency top and bottom path multiplexer is one of committed step of design ROADM.

In the photoswitch based on 2 D photon crystal, 2 * 2 directional couple photoswitches are wherein important a kind of.In directional coupled structure, obtain short coupling length and High Extinction Ratio simultaneously and have conflicting relation.In uniform directional coupled structure,, will cause short coupling length and low extinction ratio when the propagation constant of parity mode differs greatly.When if the parity mode propagation constant is more or less the same, this directional coupled structure will have long coupling length and High Extinction Ratio.In order to obtain short coupling length and High Extinction Ratio simultaneously, there is the researcher that the photonic crystal chirp structure is incorporated in this directional coupled structure.But this photon crystal structure of warbling relates to the variation of many airport radiuses, may cause bigger manufacture difficulty.In addition, this structure is a static structure, is not implemented in short coupling length and High Extinction Ratio under " opening " and " pass " two states of photoswitch.Therefore research has another committed step that 2 * 2 directional couple photoswitches of short coupling length and High Extinction Ratio are design ROADM.

Summary of the invention

The objective of the invention is at the deficiencies in the prior art, propose a kind of reconstructing light top and bottom path multiplexer based on 2 D photon crystal, it is small to have size, the advantage that integrated level is high.

For realizing this purpose, the present invention will integrate light top and bottom path multiplexer (OADM), curved waveguide and 2 * 2 photoswitches based on 2 D photon crystal and constitute a kind of novel reconstructing light top and bottom path multiplexer.

This restructural top and bottom path multiplexer based on 2 D photon crystal, it is characterized in that comprising the upper end waveguide, the lower end waveguide, set out on a journey waveguide and the waveguide of following road between the upper and lower side waveguide, and the curved waveguide of road waveguide about connecting, the two ends of curved waveguide by the photonic crystal warp architecture respectively with the waveguide of setting out on a journey, the waveguide of following road connects, curved waveguide constitutes one 2 * 2 directional couple photoswitch with the closely parallel placement of lower end waveguide, the upper end waveguide is connected with the following road microcavity of following road waveguide by point defect, and the upper end waveguide is connected with the microcavity of setting out on a journey of waveguide by point defect of setting out on a journey; Wavelength selectivity reflection microcavity is the point defect microcavity that is coupled to the upper end waveguide on one side, set out on a journey between microcavity and the following road microcavity and with road microcavity up and down apart from identical; Set out on a journey microcavity, down the resonant frequency of road microcavity and wavelength selectivity reflection microcavity is identical; The Q factor Q of waveguide on following road microcavity is decayed into ₁The Q factor Q that decays and into descend the road waveguide with following road microcavity ₂Ratio Q ₁/ Q ₂Equal 2, phase differential 2 β d along the last generation of distance of upper end wave guide direction between following road microcavity and the wavelength selectivity reflection microcavity are odd-multiple of π, wherein, d is along the distance between road microcavity and the wavelength selectivity reflection microcavity under the wave guide direction of upper end, the propagation constant of upper end wave guide mode when β is resonant frequency; The structure of microcavity of setting out on a journey and be entirely identical to down the road microcavity with the relation of wavelength selectivity reflection microcavity.Above-described three microcavitys and upper end waveguide and up and down the road waveguide constitute top and bottom path multiplexer together.When designing the 2 D photon crystal top and bottom path multiplexer in view of the above, at first obtain road microcavity and upper end waveguide of line defect single mode and the waveguide of following road under the point defect single mode.Calculate Q earlier with numerical computation method ₁/ Q ₂Be worth, the structure of road microcavity is till satisfying under just adjusting if not 2.Design the limit then and be coupled to the point defect microcavity formation wavelength selectivity reflection microcavity of upper end waveguide, make this single mode wavelength selectivity reflection microcavity have identical resonant frequency with following road microcavity.Calculate the dispersion relation of photonic crystal upper end wave guide mode simultaneously with the method for numerical evaluation,, make the phase differential that produces satisfy the odd-multiple of π so that select the distance between two microcavitys.Process only is to pass by the inverse process of journey down because set out on a journey, so the structural parameters of the microcavity of setting out on a journey and this distance of setting out on a journey between microcavity and the wavelength selectivity reflection microcavity are identical with following road microcavity relevant parameters.The wavelength selectivity reflection microcavity that is in the center can guarantee that energy is in upper end waveguide and the transfer of the total energy between the waveguide of road up and down.

Described 2 * 2 directional couple photoswitches are divided into the center coupling regime, the decoupling zone at two ends and the zone of warbling of middle transition, the medium column radius of close waveguide makes that by the variation of homogeneous the differential of this regional parity mode propagation constant is closely zero in the decoupling zone, the medium column radius of close waveguide makes the difference of this regional parity mode propagation constant increase by the variation of homogeneous in the coupling regime, warble in the zone near the medium column radius gradual change of waveguide, carry out the transition to coupling regime from the decoupling zone, the total phase differential of parity mode of two warble zone and coupling regimes is the integral multiple of π.Two decouplings zone and two warble the zone successively symmetry be distributed in the coupling regime both sides, wherein coupling regime has variable refractive index to be used for realizing switching manipulation with the zone of warbling.In the directional couple waveguide dispersion relation, the difference decision coupling length of parity mode propagation constant.At coupling regime, directional coupled structure has short coupling length and low extinction ratio.And warbling zone and decoupling zone at the interface, this structure has long coupling length and High Extinction Ratio.In order to obtain short coupling length and High Extinction Ratio simultaneously, this simple chirp structure is introduced between these two zones and reaches this purpose.It only obtains by the radius of progressive change two waveguide edge dielectric cylinders.These dielectric cylinder radiuses are far away more from coupling regime, and the amplitude that every lattice length changes is just big more, guarantee that the photon crystal wave-guide optical property changes gradually on the one hand, thereby reduce retroreflection.Also can obtain the short length of warbling on the other hand.In order to satisfy the switching manipulation before and after coupling regime and the areas diffract rate of warbling change, the length of warble zone and coupling regime is satisfied the odd even several times that the parity mode phase differential equals π by well-designed.At decoupling area change two waveguide edge dielectric cylinder radiuses, make two complete decouplings of waveguide.

A last light top and bottom path multiplexer and one 2 * 2 directional couple photoswitch that will design based on 2 D photon crystal is integrated into reconfigurable light top and bottom path multiplexer.

It is small that reconstructing light top and bottom path multiplexer of the present invention has size, and the advantage that integrated level is high is applicable to following dense wave division multipurpose optical communication system.Top and bottom path multiplexer wherein has the high characteristics of road efficient up and down, and it is short that 2 * 2 directional couple photoswitches have coupling length, the characteristics that extinction ratio is high.

Description of drawings

Fig. 1 is the ROADM structural representation based on 2 D photon crystal of the present invention.

Among Fig. 1,1 is the upper end waveguide, and 2 is the lower end waveguide, and 3 are the waveguide of setting out on a journey, and 4 are down road waveguide, and 5 be curved waveguide, and 6 are road microcavity down, and 7 for setting out on a journey microcavity, and 8 is that wavelength selectivity reflects microcavity.

Fig. 2 is 2 * 2 directional coupled structure synoptic diagram among the ROADM.

Fig. 3 is the performance plot of 2 * 2 directional coupled structures, wherein, (a) is the decoupling zone, the dispersion relation curve at coupling regime and the decoupling zone and the regional interface of warbling; (b) be under ' bar ' and ' cross ' state, as the switch extinction ratio of normalized frequency function.

Fig. 4 is the intensity transmission spectrum of three kinds of operations of this ROADM.

Fig. 5 is in the resonant wavelength position, the stable state light wave transmission mode figure of three kinds of operations of ROADM.

Embodiment

Below in conjunction with drawings and Examples technical scheme of the present invention is further described.

As shown in Figure 1, the restructural top and bottom path multiplexer based on 2 D photon crystal of the present invention's design comprises upper end waveguide 1, lower end waveguide 2, set out on a journey waveguide 3 and following road waveguide 4 between the upper and lower side waveguide, and the curved waveguide 5 of road waveguide about connecting, the two ends of curved waveguide 5 by the photonic crystal warp architecture respectively with the waveguide 3 of setting out on a journey, following road waveguide 4 connects, curved waveguide 5 constitutes one 2 * 2 directional couple photoswitch with the closely parallel placement of lower end waveguide 2, upper end waveguide 1 is connected with the following road microcavity 6 of following road waveguide 4 by point defect, and upper end waveguide 1 is connected with the microcavity 7 of setting out on a journey of waveguide 3 by point defect of setting out on a journey.Wavelength selectivity reflection microcavity 8 is the point defect microcavitys that are coupled to upper end waveguide 1 on one side, set out on a journey between microcavity 7 and the following road microcavity 6 and with road microcavity up and down apart from identical.Set out on a journey microcavity 7, down the resonant frequency of road microcavity 6 and wavelength selectivity reflection microcavity 8 is identical.The Q factor Q of upper end waveguide 1 is advanced in microcavity 6 decay in following road ₁Advance the Q factor Q of road waveguide 4 down with 6 decay of following road microcavity ₂Ratio Q ₁/ Q ₂Equal 2, phase differential 2 β d along the last generation of distance of upper end waveguide 1 direction between following road microcavity 6 and the wavelength selectivity reflection microcavity 8 are odd-multiple of π, wherein, d is along the distance between road microcavity 6 and the wavelength selectivity reflection microcavity 8 under the wave guide direction of upper end, the propagation constant of upper end wave guide mode when β is resonant frequency.The structure of microcavity 7 of setting out on a journey and be entirely identical to down road microcavity 6 with the relation of wavelength selectivity reflection microcavity 8, above-described three microcavitys and upper end waveguide and up and down the road waveguide constitute top and bottom path multiplexer together.

In a design implementation example of the present invention, this 2 D photon crystal is that the triangular crystal lattice airport on the silicon flat board is arranged.This photonic crystal only has the photon band gap (PBG) of TE (transverse electric wave, magnetic direction is parallel with the air column direction) pattern.The radius of background airport is 0.35a, and a is a grating constant here, and the relative index of refraction of silicon is 3.4.The road microcavity is that 0.526a obtains by increasing the airport radius up and down.To wavelength selectivity reflection microcavity, its point defect airport radius is 0.525a.As shown in Figure 1, in order to make each microcavity that identical resonant frequency be arranged, careful adjustment around some airport radiuses of the big airport in corresponding microcavity center.The road waveguide obtains by removing along an emptying pore of 60 ° of lattice FK direction rotations and 120 ° respectively up and down.Calculating is not having wavelength selectivity reflection microcavity, and the system transmissions frequency spectrum of following road microcavity is only arranged.Can obtain in this case under the wavelength-division demultiplexing road efficient only 42%.Can be easy to obtain this according in good time coupled mode theory descends the Q factor of road microcavity to compare Q ₁/ Q ₂Value is approximately equal to 2.These results calculate in conjunction with optimum matching layer boundary condition by the two-dimensional time-domain finite difference method and obtain.Next utilize the plane wave development method to calculate the modal dispersion relation curve of upper end waveguide, obtain the propagation constant β when this descends the road wavelength.And then according to the phase condition of 2 β d=(2n+1) π calculate between two microcavitys apart from d, n is an integer here.So wavelength selectivity reflection microcavity and up and down between the microcavity of road the distance along the upper end wave guide direction be 16a.An end of road waveguide links to each other with road microcavity up and down respectively up and down, and an other end links to each other respectively with curved waveguide two ends in the directional coupled structure by 120 ° warp architecture.This warp architecture obtains wide bandwidth high-transmission efficient by the annular air groove is set at the bending angle place.

The structure of described 2 * 2 directional couple photoswitches as shown in Figure 2, be divided into the center coupling regime, the decoupling zone at two ends and the zone of warbling of middle transition, the medium column radius of close waveguide makes that by the variation of homogeneous the differential of this regional parity mode propagation constant is closely zero in the decoupling zone, the medium column radius of close waveguide makes the difference of this regional parity mode propagation constant increase by the variation of homogeneous in the coupling regime, warble in the zone near the medium column radius gradual change of waveguide, carry out the transition to coupling regime from the decoupling zone, the total phase differential of parity mode of two warble zone and coupling regimes is the integral multiple of π.

In a design implementation example of the present invention, this directional coupler switch is made of two parallel photon crystal wave-guides of interval three emptying pores, as shown in Figure 2.This structure is divided into three parts, two decoupling zones, two zones of warbling, and a coupling regime.At coupling regime, the interface in the decoupling and the zone of warbling, and decoupling zone, the radius of two directional couple waveguides (curved waveguide and lower end waveguide) edge airport is respectively 0.38a, 0.35a and 0.31a.In the coupling and the zone of warbling, the radius of center one emptying pore is added to 0.41a between two waveguides, and this is in order to improve the difference between the coupling regime parity mode propagation constant, thereby can reduce coupling length.

Fig. 3 (a) has shown coupling regime respectively, decoupling zone and warble the zone at the interface and the dispersion relation curve in decoupling zone, and these results calculate with the plane wave development method and obtain.It is 0.239095 place that the operating frequency of pecked line display switch is arranged on normalized frequency.When the hole of coupling regime was charged into air, the propagation constant of the super mould of idol was obviously different with strange super mould propagation constant at the switching frequency of setting, shown in Fig. 3 (a).This structure has short coupling length and low extinction ratio.Opposite with this example, Fig. 3 (a) has also shown the dispersion relation curve of the photonic crystal directional coupled structure that is in coupling regime and warbles regional interface, and they represent with short dash line and solid line that respectively parity mode propagation constant difference is very little as can be seen.For such structure, we will obtain long coupling length and High Extinction Ratio.In order to overcome the contradiction between short coupling length and the High Extinction Ratio, there has been the researcher in directional coupled structure, to introduce heterogeneous texture and gone to realize.But 2 D photon crystal needs a more large-scale airport change in radius in this structure.Here, introduce two fairly simple chirp structures as the transitional region between coupling regime and the decoupling zone, they obtain by the radius of waveguide edge airport is reduced to 0.35a from 0.38a gradually.

When coupling regime was airport with the zone of warbling, the directional coupler switch structure was in ' bar ' state when the frequency of setting.And when the refractive index in these holes is changed (for example, liquid crystal charges into these airports), switch then should be in ' cross ' state.The region design of below discussion being warbled is the phase difference p of the super mould of this area unit length odd even reducing and change with border airport radius.Δ p can regard the function of the difference of the airport radius of waveguide edge and 0.35a as, and this difference table is shown Δ r, and this variable depends on propagation distance z again.The regional parity mode phase differential of warbling behind the propagation distance L so can be expressed as,

$P_{\mathrm{chirp}}={\∫}_0^L\mathrm{\Δp}\left(\mathrm{\Δr}\left(z\right)\right)\mathrm{dz}---\left(1\right)$

In these holes in the zone of warbling, charge into other medium, refractive index is 1.08 o'clock, regional waveguide edge pore radius is respectively 0.35a warbling, 0.355,0.36,0.37,0.378a when reaching 0.38a, according to the dispersion relation curve in corresponding directional couple zone, obtain the expression that Δ p changes with Δ r with the least square method quadratic fit

Δp(Δr)＝687.4576πΔr ²/a ³-12.0756πΔr/a ²+0.0292π/a (2)

The length of setting coupling regime is 5a.Relation between Δ r and the z can realize switching manipulation by design flexible.Here, the radius of these border airports progressively diminishes from 0.38a to 0.37a with per step 0.001a.And be reduced to 0.36a from 0.37a with per step 0.002a.Next, these border airport radiuses are reduced to 0.35a with per step 0.005a.Along with these radiuses are reduced, the step-length that per step airport radius changes becomes big.Reason is that parity mode propagation constant difference is with the reducing and diminish of these radiuses, so in order to obtain the step-length that little coupling length can increase these change in radius.Simultaneously, the change progressively of the optical characteristics of two waveguides quilt can avoid producing strong retroreflection.Δ r can be expressed as the functional form of z,

$\mathrm{\&Delta;r}=\left\{\begin{array}{c}0.005z,(0\&le;z<2a)\\ 0.002z+0.006a,(2a\&le;z<7a)\\ 0.001z+0.013a,(7a\&le;z<17a)\\ -0.001z+0.051a,(21a\&le;z<31a)\\ -0.002z+0.02a,(31a\&le;z<36a)\\ -0.005z+0.19a,(36a\&le;z\&le;38a)\end{array}\right.---\left(3\right)$

So in this directional couple, the total phase differential of parity modes can obtain by the parity mode phase differential that calculates the coupling regime and the zone of warbling respectively,

P _total＝P _coupling+2P _chirp (4)

At the switching frequency of setting, according to equation (1) and (4), the total phase differential between the super mould of odd even is 4.74 π.

In these holes in the zone of warbling, when charging into air, be respectively 0.35a according to the regional waveguide edge airport radius of warbling, dispersion relation when 0.375a and 0.38a, the quadratic fit that can obtain Δ p represents,

Δp＝36.8177πΔr ²/a ³+8.7647πΔr/a ²+0.0057π/a (5)

In the decoupling zone, the dispersion relation curve display of parity mode is in Fig. 3 (a).At the switching frequency of setting, because the super mould of odd even has identical propagation constant, so two waveguides can realize complete decoupling.According to above Equation for Calculating, the total phase differential between the super mould of odd even is 8.132 π.In Fig. 2, when port one as the incident end, calculated this structure with the finite time-domain difference method.As Fig. 3 (b), at the switching frequency place that sets, 4 pairs of ports 2 of port are-30.52dB, the retroreflection of port 3 to the extinction ratio of port 2 be-17.92dB. this confirmed that switch is in ' bar ' state.This total phase differential is near the even-multiple of π, and this explanation can be used for designing chirp structure with this result.Along with the coupling regime and the regional hole refractive index of warbling become 1.08, coupling regime and decoupling zone are presented among Fig. 3 (a) with the dispersion curve at the regional interface of warbling.According to the total phase differential of above result of calculation is the odd-multiple that 4.74 π approach π.When light when port one is imported, shown in Fig. 3 (b), the extinction ratio of port 2 and 3 pairs of ports 4 is respectively-34.55dB and-22.27dB.Illustrate that this moment, switch was in " cross " state.Because match or phase place have reasons such as transition with step change, total the phase value by the dispersion relation curve calculation of this moment has bigger departing from from 5 π, but these calculating still can be used for designing chirp structure to satisfy the needs of realizing on off state.Because the little variations in refractive index in these holes, corresponding dispersion curve when the dispersion relation at coupling regime and coupling regime and interface, decoupling zone is similar to these holes and charges into air.At the interface of warbling zone and coupling regime and decoupling zone, avoid the optical property mismatch of waveguide so, thereby avoided producing bigger retroreflection.

Calculated restructural shown in Figure 1 road add-drop multiplexer architecture up and down with the time domain finite difference method at last.When light wave when port A incident and switch are in ' cross ' state, at port B, the transmission spectrum at C and D place is presented among Fig. 4 (a), the transmission signals of setting wavelength can be with surpassing under 90% the efficient road to port D.Same, as port C during as the incident end, port A, the transmission spectrum of B and D are presented among Fig. 4 (b), and the signal band and surpassed 90% following road efficient and can upload to port B.Shown in Fig. 4 (c), when this 2 * 2 switch is in the OFF state,, following road signal can realize that the energy above 80% uploads to port B again thereby can uploading to the waveguide of setting out on a journey once more by the waveguide of setting out on a journey.The loss of signal comes from the reflection accumulation of these photonic crystal optical devices.Fig. 5 (a) (b) and (c) has shown that respectively the stationary field that emission operative wavelength continuous wave obtains under these three kinds of operational circumstances distributes.

Analog result shows that reconstructing light top and bottom path multiplexer of the present invention (ROADM) can dispose wavelength channel and carry out dynamic wavelength route at optical network node.When the communication window operative wavelength was 1550nm, the size of this device architecture was 30 μ m * 22 μ m, was far smaller than the size of present traditional devices.Therefore, it is small that reconstructing light top and bottom path multiplexer of the present invention has size, and the advantage that integrated level is high is applicable to following dense wave division multipurpose optical communication system.Top and bottom path multiplexer wherein has the high characteristics of road efficient up and down, and it is short that 2 * 2 directional couple photoswitches have coupling length, the characteristics that extinction ratio is high.

Claims (1)

1, a kind of restructural top and bottom path multiplexer based on 2 D photon crystal, it is characterized in that comprising upper end waveguide (1), lower end waveguide (2), waveguide of setting out on a journey (3) between the upper and lower side waveguide and following road waveguide (4), and the curved waveguide (5) of road waveguide about connecting, the two ends of curved waveguide (5) by the photonic crystal warp architecture respectively with the waveguide of setting out on a journey (3), following road waveguide (4) connects, curved waveguide (5) constitutes one 2 * 2 directional couple photoswitch with the closely parallel placement of lower end waveguide (2), upper end waveguide (1) is connected with the following road microcavity (6) of following road waveguide (4) by point defect, and upper end waveguide (1) is connected with the microcavity of setting out on a journey (7) of the waveguide of setting out on a journey (3) by point defect; Wavelength selectivity reflection microcavity (8) is the point defect microcavity that is coupled to upper end waveguide (1) on one side, be positioned between the microcavity of setting out on a journey (7) and the following road microcavity (6) and with road microcavity up and down apart from identical; Set out on a journey microcavity (7), down the resonant frequency of road microcavity (6) and wavelength selectivity reflection microcavity (8) is identical; The Q factor Q of upper end waveguide (1) is advanced in following road microcavity (6) decay ₁Advance the Q factor Q of road waveguide (4) down with following road microcavity (6) decay ₂Ratio Q ₁/ Q ₂Equal 2, phase differential 2 β d along the last generation of distance of upper end waveguide (1) direction between following road microcavity (6) and the wavelength selectivity reflection microcavity (8) are odd-multiple of π, wherein, d is along the distance between road microcavity (6) and the wavelength selectivity reflection microcavity (8) under the wave guide direction of upper end, the propagation constant of upper end wave guide mode when β is resonant frequency, the structure of microcavity (7) of setting out on a journey and be entirely identical to down road microcavity (6) with the relation of wavelength selectivity reflection microcavity (8), above-described three microcavitys and upper end waveguide and up and down the road waveguide constitute top and bottom path multiplexer together; Described 2 * 2 directional couple photoswitches are divided into a center coupling regime, the decoupling zone at two ends and the zone of warbling of two middle transition, the medium column radius of close waveguide makes that by the variation of homogeneous the differential of this regional parity mode propagation constant is closely zero in the decoupling zone, the medium column radius of close waveguide makes the difference of this regional parity mode propagation constant increase by the variation of homogeneous in the coupling regime, warble in the zone near the medium column radius gradual change of waveguide, carry out the transition to coupling regime from the decoupling zone, the total phase differential of parity mode of two warble zone and coupling regimes is the integral multiple of π.

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