CN100350292C - Two-dimensional micro-electromechanical optical switch using shuffle Benes interstage join rule and method thereof - Google Patents

Abstract

The present invention relates to a method for producing a two-dimension micro light electric and mechanical optical switch, particularly to an optical switch which is produced by the method, and an optical crossing connector which uses the optical switch and is used for a net-shaped wavelength division multiplex optical network. The method comprises the following steps: a 2 log 2 N-1 stage is arranged in an N*N Benes interconnect system, wherein an N is the input/output numbers; the middle stage is a first stage; all levels are orderly marked with a second stage, a third stage till the log 2n stage from the middle part to two sides. The horizontal distance between every two stages from the first stage is 2< log 2N-2 >p, 2< log 2N-3 >p to 2p, p, wherein the p is the distance between adjacent movable micro lenses, and thus, the matrix array of the movable micro lenses is formed, and fixing micro lenses are fixedly formed on the middle lines of two adjacent stages, and are mutually, in parallel, and vertically positioned with substrates. The method adopts interconnect rule of shuffle Benes interstage and is suitable for producing the micro light electric and mechanical optical switch with big port numbers. The using numbers of needed micro lenses are minimum. The present invention loosens the limit of processing technology and crystal wafer size, simultaneously reduces beam divergence loss, reduces the size of micro lenses and the crystal wafer, enhances the repeatability from one port to another and reduces power loss.

Description

Employing shuffle the two-dimensional micro electromechanical photoswitch and the method thereof of Benes inter-stage concatenate rule

Technical field

The present invention relates to the optical communication technique field, particularly a kind of two-dimensional micro electromechanical photoswitch and method thereof are applicable to the optical cross connect networking of optical communication of wavelength-division multiplex and the optical switching system that light path is switched.

Background technology

Along with the use with the high capacity wave division multiplexing transmission system of increasing rapidly of communication service, the requirement of exchange capacity and network reliability is also increased by a wide margin.The configuration optical cross-connect is very important in netted long-reach wavelength division multiplexing optical-fiber network, and this device is finished the exchange of light signal in the light territory, carries out resource reservation and finishes the protection recovery.And along with the sustained growth of network size and increasing sharply of optical fiber/number of wavelengths, the demand of large port being counted optical cross-connect is more and more urgent.In the optical switching technique of the construction optical cross-connect of reporting, low-light electromechanical technology is to build large port to count the most promising a kind of technology of photoswitch, mainly be since its to have a low cross-talk, polarization insensitive, wavelength insensitive, to bit rate with data layout is transparent and can be integrated in the first-class inherent advantages of chip piece to light, electricity and physical construction.

Low-light electromechanical photoswitch arrives output port by rotational micromirror route light beam from input port.The low-light electromechanical photoswitch that proposes has two kinds at present: two-dimentional switch and three-dimensional switch.Micro mirror in the three-dimensional switch rotates on three Spatial Dimensions, and each micro mirror can be in a plurality of positions.For example, in the photoswitch of a N * N, each micro mirror can be in N position.Because this three-dimensional light switch only uses 2N micro mirror.Therefore, expectation utilizes its optical cross-connect of realizing the large port number, such as N is greater than 32.But, multipoint micro mirror array to manufacture process requirement extremely strictness and the control accuracy utmost point cannot say for sure card, thereby influenced stability, reliability and the cost of system.

Two-dimensional micro electromechanical photoswitch is the most ripe photoswitch based on low-light electromechanical technology, and wherein, micro mirror only rotates on two Spatial Dimensions, and two states are only arranged: " opening " state and " pass " state.Obviously, this scale-of-two control is simple, and can directly realize with digital circuit.Current, the micro mirror in the two-dimentional switch is placed on the silicon substrate according to the parallel decussate texture of N * N, and characteristic and control algolithm that it has strictly non-blocking are simple.But parallel decussate texture needs N ²Individual micro mirror; In order to guarantee certain beam spread loss, along with the increase of N, the necessary corresponding growth of micromirror size, still, this has brought great difficulty for again manufacturing process and control.And because the restriction of manufacture craft, the distance between the micro mirror is proportional to the micro mirror radius usually, and this can increase the size of parallel decussate texture photoswitch.In addition, in the Foundry Works the higher wafer size of yield rate usually at 1cm ²About, limited the quantity and the corresponding ports number of micro mirror.Therefore, up to the present, the port number of commercial two-dimensional micro electromechanical photoswitch mostly is 32 most.The repeatability of the port-to-port that another significant problem is parallel decussate texture is poor, that is to say, and is the longest very big with difference shortest path, can cause that the loss between the different port is inconsistent.In order to build the photoswitch of large port number, multilevel two-dimensional low-light electromechanical optical switch construction proposes, still, and the cost height of the interconnection fabric that the photoswitch loss of these structures is big and a large amount of.Though integrated multilevel two-dimensional low-light electromechanical photoswitch has been eliminated the inter-stage interconnection fabric, but, with 2 * 2 optical switch modules is that the photoswitch that elementary cell directly uses Benes interconnection rule to make up has used a large amount of concave mirrors and rotatable micro mirror, this can cause very big reflection loss, and the manufacture craft of concave mirror is very complicated; And the photoswitch of the parallel decussate texture of revising is subjected to the restriction of above-mentioned manufacture craft and wafer size all the time.

Many counting in the framework of photoswitch based on 2 * 2 switch modules construction large port of having proposed, the multistage interconnected framework of Benes is to use the framework of 2 * 2 switch module number minimums.N * N Benes switch configuration needs N (log ₂N-1/2) individual micro mirror is far smaller than the required N of parallel decussate texture ²Individual micro mirror.It is the choke free displacement photoswitch of a restructural framework, and the point-to-point connection of promptly setting up between arbitrary idle input port and any idle output port may need the connection of having set up is reset.The clog-free less use of restructural in traditional electric treatment network, because port number is huge, the path of reconstruct is oversize computing time, might be greater than connection setup time.In wavelength division multiplexed optical network, port number can lack much with respect to electric network, and because optical fiber/wavelength loaded service amount is huge, be generally several gigabits, or even bit or higher too, and the duration is very long, so acceptable connection setup time can be very long.Therefore, the reconfigurable optical switch is applicable to optical-fiber network, and, reduced required optical switch module number significantly.

Summary of the invention

Technical matters to be solved by this invention is to provide a kind of new integrated multilevel low-light electromechanical micro mirror light switch design method.This method adopts the Benes inter-stage interconnection rule of shuffling, and it is very suitable for building the two-dimensional micro electromechanical photoswitch of large port number.And it makes required micro mirror number reach minimum, loosen the restriction of above-mentioned manufacture craft and wafer size, improved performance simultaneously, such as: the beam spread loss reduced, reduced micromirror size and wafer size, strengthened the repeatability of port-to-port and reduced power attenuation.

Because beam propagation must be observed reflection law, promptly incident angle equals reflection angle, and therefore the light that is reflected by micro mirror can not be propagated along any direction.If as module among Fig. 4 (4,1,1), realize that it is impossible that a branch of in the two bundle incident lights propagates simultaneously according to light gray paths that another restraints according to the Dark grey propagated with a Double sided mirror.Therefore, build the photoswitch satisfy the Benes interconnected relationship as the basic switch module, the rearrangement of must shuffling of the position of basic module in the Benes framework with the simplest 2 * 2 two-dimensional micro electro-mechanical switches/Double sided mirrors.Through scrutinizing, find that be the integrated multilevel two-dimensional low-light electromechanical photoswitch of basic module as long as each grade optical switch module, can be built what satisfy that Benes interconnection rule satisfies reflection law simultaneously according to certain reordering rule and increase some fixedly micro mirrors of shuffling with 2 * 2 Double sided mirror optical switch modules.

First aspect present invention provides a kind of method of constructing two-dimensional micro electromechanical photoswitch, and it may further comprise the steps: structure N * N photoswitch need be provided with 2log ₂The N-1 level, wherein N is the input/output end port number, intergrade is the 1st grade, with at different levels by the centre to both sides be labeled as the 2nd grade, 3rd level successively, until log ₂The N level.Wherein each grade made up by movable the simplest in other words 2 * 2 two-dimensional micro electromechanical optical switch modules of micro mirror of the N/2 that lines up a team from top to bottom, this N/2 movable micro mirror minute surface be parallel to each other and per two adjacent movable micro mirrors between distance be p.Corresponding movable micro mirror is on the same horizontal line between all levels, constitutes matrix structure.And, be 2 since the horizontal range between the 1st grade of every two-stage ^Log2N-2P, 2 ^Log2N-3P ..., 2p, p, so just constituted the matrix array of movable micro mirror, on the center line of two adjacent levels, place and maintain static, be parallel to each other and perpendicular to the fixedly micro mirror of substrate.

And then according to the method for the structure two-dimensional micro electromechanical photoswitch that the third aspect provided of first aspect present invention, wherein said fixedly micro mirror is installed according to the following steps: the 1st step, the fixing micro mirror of N/2 of configuration on the center line of the 1st grade and the 2nd inter-stage, it is divided into two parts up and down, every part by N/4 fixedly micro mirror forms and adjacent fixed micro mirror p apart, there is the individual fixedly micro mirror of N/8 to be in the movable micro mirror array zone in every part, and fixedly micro mirror wherein is in same horizontal line with corresponding movable micro mirror, and the individual fixedly micro mirror of all the other N/8 is in beyond the movable micro mirror array zone; The 2nd step, the fixing micro mirrors of two groups of configurations on the center line between the 2nd grade and 3rd level, every group fixedly the configuration mode of micro mirror is similar with the configuration mode between the 1st grade and the 2nd grade, but every group of required fixedly micro mirror number is for its half be N/4, correspondingly, also the movable micro mirror in the 2nd grade and the 3rd level is divided into two groups, every from top to bottom N/4 is one group, allow every group of fixedly corresponding every group of movable micro mirror of micro mirror, two parts about fixedly micro mirror is divided into every group then, every part is made up of the individual fixedly micro mirror of N/8, and the fixedly micro mirror minute surface of every part is parallel to each other and at a distance of p, micro mirror in every part in fixedly micro mirror of half and the movable micro mirror array of respective sets is on the same horizontal line, and second half is in beyond the movable micro mirror array zone; Up to the s step, on the center line of s level and s+1 inter-stage, dispose 2 ^S-1Group is micro mirror fixedly, correspondingly, and the movable micro mirror per from top to bottom 2 of s level and s+1 level ^Log2N-sIndividual mirror is one group, totally 2 ^S-1Group, every group fixedly micro mirror is corresponding with every group of movable micro mirror, two parts about every group fixedly micro mirror is divided into, every part is by 2 ^Log2N-s-1Individual mirror composition and neighboring micro are at a distance of p.The micro mirror of half is in the array region that the movable micro mirror group of corresponding group constituted in every part, and is in same horizontal line with corresponding movable micro mirror minute surface, and second half micro mirror is in beyond the movable micro mirror array of the corresponding group zone.Repeat above-mentioned steps, the micro mirror between every two-stage is all settled and is finished.Wherein, log ₂N-1 and log ₂Between the N level, the fixedly micro mirror of the top in every group is in the horizontal top that the movable micro mirror minute surface of the top delegation of corresponding group in the movable micro mirror array constitutes

The place, following fixedly micro mirror is in the horizontal below of the movable micro mirror minute surface formation of delegation bottom of corresponding group in the movable micro mirror array

The place; And the fixedly micro mirror of two adjacent groups location overlap replaces with Double sided mirror, that is, required fixedly micro mirror number is between s level and the s+1 level

Wherein, the Double sided mirror number is

Therefore, construct a N * N two-dimensional micro electromechanical photoswitch, required fixedly micro mirror adds up to

Wherein, Double sided mirror adds up to

According to the described method of first aspect present invention, when described movable micro mirror is 2 * 2 two-dimensional micro electromechanical optical switch modules, its movable micro mirror array and the fixing micro mirror array N * N photoswitch of realizing having the Benes interconnected relationship jointly, but its each movable micro mirror or 2 * 2 optical switch module positions are with respect to the rearrangement of must shuffling of each 2 * 2 optical switch module position in traditional N * N Benes interconnect architecture, now define the module No. of describing each 2 * 2 optical switch modules position in framework in traditional N * N Benes interconnect architecture, this module No. is defined by following method: traditional N * NBenes interconnect architecture is removed the ragged edge two-stage, the network that all intergrades constitute is symmetrical up and down, identical two parts, every part all is Benes networks of N/2 * N/2, and the module of each part only is connected with module in this part, each part in these two parts is again to remove the ragged edge two-stage, the centre is to be made of the Benes network of two N/4 * N/4 up and down, module in the s level is correspondingly divided into groups, the module that guarantees the s-1 level that the module in every group connects does not have identical, like this, log ₂The N level comprises one group, is labeled as group 1; Log ₂The N-1 level comprises two groups, is labeled as group 1, group 2 from top to bottom; The group number of s level is 1/2 of a s-1 level; The 2nd grade is divided into N/4 group, is labeled as group 1 from top to bottom, and group 2 is up to group N/4; The 1st grade is divided into N/2 group, is labeled as group 1 from top to bottom, group 2, up to group N/2, in each group, module is labeled as 1 from top to bottom, 2, and the like, like this, array (the s that each 2 * 2 switch module can constitute with three numbers, g m) comes mark, and s represents level number in this array, g represents the group number in this grade, and m represents the module No. in this group.

Described according to a third aspect of the invention we method, wherein said movable micro mirror is determined by following steps corresponding to the module No. of corresponding module in traditional N * N Benes interconnect architecture:

The 1st step is at s level, s=log ₂N-n, wherein n=(0,1 ..., log ₂N-1), the micromirror position of arranging from top to bottom in movable this level of micro mirror array is pressed the module No. that the m value is arranged from small to large corresponding to this level in the traditional B enes interconnect architecture successively, and the module No. that the m value is identical has 2 ⁿIndividual, 2 of correspondence ⁿIndividual micromirror position is first position to the 2 from top to bottom ⁿIndividual position, module No. (s, 1, m) corresponding to the micro mirror that is in first position, module No. (s, 2, m) corresponding to be in first position at a distance of 2 ^N-1The 2nd of p ^N-1The micro mirror of+1 position;

The 2nd step was a benchmark with this two sides mirror micro mirror, the mirror micro mirror (s, 1, m) below with its at a distance of 2 ^N-2The 2nd of p ^N-2The mirror micro mirror of+1 position corresponding to module No. (s, 3, m); The mirror micro mirror (s, 2, m) below with its at a distance of 2 ^N-2The 2nd of p ^N-1+ 2 ^N-2The mirror micro mirror of+1 position corresponding to module No. (s, 4, m);

The 3rd step, successively with determined the position (s, 1, m), (s, 2, m), (s, 3, m), (s, 4, m) be benchmark, in its lower section with its apart the position of 2n-3p micro mirror corresponding to module No. (s, 5, m), (s, 6, m), (s, 7, m), (s, 8, m);

If also have the module No. of micro mirror not determine, just continue; Q (step of 1≤q≤s+1), continue according to these the group number of the micro mirror of determination module number be benchmark with the position of these modules successively from small to large, in its lower section with its at a distance of 2 ^N-lThe micro mirror corresponding group number m of the order module No. from small to large of the position of p, wherein l represents the l step;

Until the s+1 step, the module No. of all micromirror position correspondences is all definite.

A kind of optical cross-connect that is used for long-distance netted wavelength division multiplexed optical network, it has foregoing two-dimensional micro electromechanical photoswitch.

Description of drawings

Below with reference to accompanying drawing exemplary embodiment of the present invention is described in detail, wherein:

Accompanying drawing 1 is the parallel decussate texture switches of 4 * 4 two-dimensional micro electromechanical;

Accompanying drawing 2 is longitudinal cross-sections that the Gaussian beam among Fig. 1 is propagated to input light 4 from input light 1;

Accompanying drawing 3 (a) is 2 * 2 examples based on the closed low-light electro-mechanical switches in the slit of stress and static;

Accompanying drawing 3 (b) is the floor map of presentation graphs 3 (a);

Accompanying drawing 4 is structure and mechanism synoptic diagram of 16 * 16 traditional B enes photoswitches;

Accompanying drawing 5 is according to 16 * 16 low-light electromechanical of the present invention the shuffle structure and the mechanism synoptic diagram of Benes photoswitch;

Accompanying drawing 6 is comparisons of the longest path length in two kinds of structures under the different port number;

Accompanying drawing 7 (a) is the comparison of w (D) in two kinds of structures under the different port number;

Accompanying drawing 7 (b) is the comparison of chip area in two kinds of structures under the different port number.

Embodiment

Fig. 1 has illustrated the structure and the mechanism of two-dimentional parallel decussate texture switch.The feature of the parallel decussate texture switch of two dimension is an integrated micro mirror array on single silicon chip, and the parallel beam of carrying light signal is propagated in chip surface.Usually, it is used as permutator, and has the strictly non-blocking feature, that is, the input of any free time can be connected to the output of any free time and not interrupt the connection of having set up.The parallel cross bar switch of N * N needs N ²Individual micro mirror, this number can increase rapidly along with the increase of N.Fig. 1 is the parallel decussate texture switches of 4 * 4 two-dimensional micro electromechanical.The mirror of solid line represents that this mirror is in " opening " state; The mirror of dotted line represents that this mirror is in " pass " state.1 _{Go into}→ 4 _{Go out}Light beam is through the longest path; And 4 _{Go into}→ 1 _{Go out}Light beam is through the shortest path.P is two distances between the contiguous mirror, also is called the cycle; Emission/reception plane and be p/2 apart from the distance between its nearest mirror.Wherein, each micro mirror is a single-surface mirror, has " opening " and " pass " two states.Each mirror is demarcated by the position in its matrix of living in.When m input port will exchange to n output port, (m n) is in " opening " state to mirror, and folded light beam is input to n output from m.And, in every row and every row, have only a micro mirror to be in " opening " state at one time.According to Fig. 1,1 go into → 4 connections between going out are by the longest path, 7p; And 4 _{Go into}→ 1 _{Go out}By the shortest path, p.For the parallel decussate texture switch of N * N, the longest path is p for (2N-1) p shortest path length.As seen, the difference of two paths is (2N-2) p.In the low-light electromechanical photoswitch, the loss of luminous power is determined by Several Factors: the Gaussian beam diffusion, and absorption of air, the mistuning of micro mirror angle is whole, micro mirror reflection loss, the coupling loss between the bending of micro mirror minute surface and optical fiber and the photoswitch.The loss that three factors in back cause is a constant, and is irrelevant with the port number of photoswitch.The loss that first three factor causes increases along with the increase of the path of light beam experience., mainly pay close attention to the loss that beam spread causes herein, because it is the main factor of restriction two-dimensional micro electromechanical photoswitch input/output end port number.

Fig. 2 has illustrated the communication process of light beam from the input optical fibre to the output optical fibre, and the path among the figure is deployed on the straight line.Mirror (1,4) is in " opening " state.In order to make pattern match, lens converge a little to light beam, make waist be in the mid point of optical path.In free space, laser beam is a Gaussian beam.The electric field of Gaussian beam is the function of axial coordinate z and polar coordinates r, expression formula as shown in the formula:

$E(r,z)={\mathrm{<figure-callout\; id="0"\; label="E"\; filenames="C20041000924900232.png"\; state="\{\{state\}\}">E</figure-callout>}}_0\&times;\frac{\mathrm{\&omega;}}{\mathrm{\&omega;}\left(z\right)}\exp \{-{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="C20041000924900231.png,C20041000924900251.png"\; state="\{\{state\}\}">r</figure-callout>}}^2/\mathrm{\&omega;}{\left(z\right)}^2\}$ Amplitude factor

$\&times;\exp \{-j[\mathrm{kz}-{\tan }^{-1}\left(\frac{z}{z_0}\right)\left]\right)\}$ Vertical factor

* exp{-jkr ²/ 2R (z) } phase factor

——(1)

Wherein, the z-propagation distance, ω (z)-amplitude fading becomes with z to the beam radius at 1/e place, and R (z)-wavefront curvature becomes with z.

For the Gauss who is described in the beam propagation expands Shu Xiaoying, ω (z) and R (z) are described by following formula:

$\mathrm{\&omega;}\left(z\right)={\mathrm{\&omega;}}_0\sqrt{1+{\left(\frac{z}{z_0}\right)}^2}---\left(2\right)$

$R\left(z\right)=z[1+{\left(\frac{z}{z_0}\right)}^2]---\left(3\right)$

Wherein, ${\mathrm{<figure-callout\; id="0"\; label="z"\; filenames="C20041000924900232.png"\; state="\{\{state\}\}">z</figure-callout>}}_0=\frac{2{\mathrm{\&pi;<figure-callout\; id="0"\; label="w"\; filenames="C20041000924900232.png"\; state="\{\{state\}\}">w</figure-callout>}}_0}{\mathrm{\&lambda;}}$ The path that (λ is a signal wavelength)-Rayleigh scope is a beam radius by minimum value is experienced when rising to  times of minimum value De.w ₀-minimum beam radius is called waist, is decided by the lens that place the input optical fibre front.

Spreading because light beam is Gauss, is that the luminous power of micro mirror reflection of r is as follows through z place radius:

If make micro mirror radius r=1.5 ω (z), optical power loss is 1.1%, supposes that specular reflectance is 98%, and the optical power loss that is caused by micro mirror is about 3%.

And, when lens are used as collimating mirror, go into the focus that optical fiber is positioned at lens, at this moment w ₀Be in-the D place.Because the expansion Shu Xiaoying of Gaussian beam, the optical fiber coupling loss of I/O place can increase by a wide margin along with the increase of path.As shown in Figure 2, in order to realize zero coupling loss, adopt pattern match, it is a little promptly to go into the optical fiber slow astern, is in the outside of focus, and at this moment incident beam is converged slightly, correspondingly, and w ₀Be positioned at coordinate O point.By preceding described, the micro mirror radius must be greater than 1.5 ω (z).In order to minimize micromirror size, can get by formula (2) and (4), at z ₀The minimum value that=D obtains at the place w (D) is Except the restriction of w (D), make the size that restriction also determines D.At document Lih Y Lin, Evan L.Goldstein, and Robert W.Tkach, " On the Expandability of Free-SpaceMicromachined Optical Cross Connects; " J.Lightwave Tech., 18 (4), among the 482-489 (2000), owing to make restriction, cycle (distance between the micro mirror of two vicinities) is got 3r+800um, otherwise if the distance between the mirror is too near, the yield rate of the micro mirror array of making is not high.Because the restriction of beam radius and manufacturing restriction have determined w (D) and D value jointly.Minimum w (D) value of making the two-dimensional micro electromechanical photoswitch of 16 * 16 parallel decussate textures is 150.28, and the minimum w (D) that makes 32 * 32 photoswitches is 242.44um.This requires the size of micro mirror too big, and making and control are all very difficult.

Next, consider the dimensional problem of photoswitch.By analysis, when micromirror size is bigger, obtain approximate formula:

w _{Parallel intersection}(D)=N κ (2 λ/π) (5)

D _{Parallel intersection}=N ²κ ²(2 λ/π) (6)

Wherein, κ is a proportionality constant.Show, along with input/output end port is counted N and is increased, the growth that is directly proportional of micro mirror radius; And required wafer size (is approximately D ²) one-tenth N ⁴Increase.Otherwise the Gaussian beam diffusional effect causes huge optical power loss.Therefore, parallel decussate texture is not suitable for being used for making large port and counts photoswitch.

Fig. 3 is the simplest 2 * 2 two-dimensional micro electromechanical micro mirror optical switch modules, and Fig. 3 (a) is 2 * 2 examples based on the closed low-light electro-mechanical switches in the slit of stress and static; Fig. 3 (b) is the floor map of expression (a).Left side figure is the propagation path of light figure that Double sided mirror is in the D score position, and this moment, photoswitch was " parallel " state; Right figure be Double sided mirror be in " on " the propagation path of light figure of position, photoswitch is " intersection " state at this moment.From the discussion of front as can be known, the two-dimensional micro electromechanical micro mirror photoswitch based on parallel decussate texture needs 4 single-surface mirrors.At document M.Wu, " Micromachining for Optical andOptoelectronic Systems, " Proc.IEEE, 85, propose simple two-dimensional low-light electromechanical micro mirror 2 * 2 optical switch modules among the 1833-56 (1997), only used a Double sided mirror.Fig. 3 has illustrated its structure and operation mechanism.When Double sided mirror is in the position of D score, it reflects two bundle incident lights simultaneously to corresponding output port, and promptly 1 _{Go into}→ 1 _{Go out}And 2 _{Go into}→ 2 _{Go out}Connect and set up, realize " parallel " state.Otherwise, when Double sided mirror be in " on " the position, two bundle incident lights are through to the corresponding output end mouth, promptly 1 _{Go into}→ 2 _{Go out}And 2 _{Go into}→ 1 _{Go out}Connect and set up, realize " intersection " state.

In Fig. 3, clearly, adopt 2 * 2 two-dimensional micro electromechanical photoswitches of Double sided mirror to make the decreased number of required micro mirror arrive minimum, correspondingly, simplified control system, reduced cost.From performance perspective, plane of incidence and receive between the plane distance can be very near, so, compare with parallel decussate texture switch, greatly reduced because the loss that the Gaussian beam diffusion causes.And because all propagation path are isometric, so the loss of walking different optical paths generations is identical, promptly port-to-port is repeatable fine.In addition, clearly, wafer size (photoswitch size) can be reduced into original 1/4.

The closed electrostatic actuator in slit (as shown in Figure 3) is to think the design that is suitable for implementing Double sided mirror low-light electro-mechanical switches most, because this driver floor area is little and scope of activities is big.This driver is to make ground by plating layer of metal on the polysilicon.After finishing etching, the stress official post driver between polysilicon and the gold layer is bent upwards.When voltage is applied between driver and the substrate, electrostatic attraction moves down driver.And the whole optical power loss that causes of angle mistuning has been avoided in this design.

Therefore, the key for the photoswitch that utilizes a large port number of the simplest this 2 * 2 low-light electro-mechanical switches module constructions is suitable photoswitch framework of design.Though someone proposes the framework based on 2 * 2 switch modules,, the required micro mirror number of this photoswitch is too much, and corresponding optical loss can be excessive.Therefore, academia and industry member expect that all new framework occurs.

Fig. 4 is the structure and the mechanism synoptic diagram of 16 * 16 traditional B enes photoswitches.It comprises 7 grades, is denoted as the 1st grade, and the 2nd grade, 3rd level, the 4th grade.Each square among Fig. 4 is represented 2 * 2 switch modules.Array in the module (s, g m) are the label of this module, wherein, and s-level number, the group number in this level of g-, the module No. during m-should organize.Connect 1 _{Go into}→ 15 _{Go out}With 2 _{Go into}→ 1 _{Go out}The mechanism of this structure is described.

The method of the photoswitch based on the Benes reordering rule of shuffling of the present invention and the Benes rule of shuffling make up in such a way:

First specific embodiment

In N * N Benes interconnection system, there is 2log ₂N-1 level (wherein, N is the input/output end port number).The incident angle of supposing light beam is 45 °.Wherein each grade made up by the simplest in other words 2 * 2 two-dimensional micro electro-mechanical switches modules of the N/2 that lines up an a team from top to bottom Double sided mirror, this N/2 micro mirror minute surface be parallel to each other and per two neighboring micros between distance be p.Corresponding micro mirror is on the same horizontal line between all levels, constitutes matrix structure.As shown in Figure 4, the Benes interconnection structure is to be axis of symmetry with intergrade, and is symmetrical.Correspondingly, the intergrade of mark is the 1st grade, is labeled as the 2nd grade one by one from the centre to both sides, 3rd level ..., log ₂The N level.With the 1st grade is that the center begins to settle each level, and the horizontal range between the 1st grade and the 2nd grade is 2 ^Log2N-2Horizontal range between the p, the 2nd grade and 3rd level is 2 ^Log2N-3P, every increase one-level, s (s represents the integer of level number, gets 1,2 ..., log ₂N) and the horizontal range between the s-1 level be kept to 1/2 of horizontal range between s-1 and the s-2 level, up to log ₂N-1 and log ₂Horizontal range between the N is p.That is to say that since the 1st grade, the horizontal range between every two-stage is 2 ^Log2N-2P, 2 ^Log2N-3P ..., 4p, 2p, p.So just constituted the array of the matrix form of movable micro mirror.As shown in Figure 5, since the 1st grade to the 4th grade, the horizontal interval between every two-stage is 4p, 2p, p.

For light beam relay that switch module in each grade is transmitted connection in the corresponding switch module of the right adjacent level, on the center line of two adjacent levels, place and maintain static, be parallel to each other and finish this function perpendicular to the micro mirror of substrate to continue between multistage.For example: among Fig. 5 fixedly micro mirror A can be used for reflection and pass to switch module (2,1,1) from the light beam that switch module (1,1,1) comes, make the two-beam of switch module (1,1,1) outgoing can conduct to (2,1,1) and (2,2,1), guaranteed that Benes interconnection rule is the annexation among Fig. 4.The first step disposes the fixedly micro mirror between the 1st grade and the 2nd grade.Need N/2 fixing micro mirror between the 1st grade and the 2nd grade, this N/2 micro mirror is all on the center line between these two levels.They are divided into two parts, every part form by N/4 micro mirror and neighboring micro at a distance of p.A part places the top, and another part places bottom.And the micro mirror that half number is arranged in every part is that N/8 micro mirror is in the movable micro mirror array zone, and micro mirror wherein and corresponding movable micromirror are in same horizontal line; Second half, N/8 micro mirror is in beyond the movable micro mirror array zone.In the 2nd step, dispose the fixedly micro mirror between the 2nd grade and the 3rd level.Required fixedly micro mirror all is on their center line between the 2nd grade and the 3rd level, and is divided into two groups.The situation of every group of micro mirror is similar with the situation between the 1st grade and the 2nd grade, but every group of required micro mirror number is for its half be that N/4 is individual.Correspondingly, respectively the movable micro mirror in the 2nd grade and the 3rd level is divided into two groups, every from top to bottom N/4 is one group.Allow every group of fixedly corresponding every group of movable micro mirror of micro mirror.Then, every group fixedly micro mirror be divided into two parts, every part is made up of N/8 micro mirror, and the micro mirror minute surface of every portion is parallel to each other and at a distance of p.Micro mirror in every part in micro mirror of half and the movable micro mirror array is on the same horizontal line; Second half is in beyond the movable micro mirror array zone.Settle fixedly micro mirror according to such method, two adjacent groups fixedly micro mirror has locational overlappingly, at this moment can finish the task that continues of two groups of micro mirrors simultaneously, as micro mirror C, the D among Fig. 5 the micro mirror of overlapping with a fixing Double sided mirror replacement.In the s step, the required fixedly micro mirror of s level and s+1 level all is on their center line, and is divided into 2 ^S-1Group.Correspondingly, the movable micro mirror per from top to bottom 2 of s level and s+1 level ^Log2N-sIndividual mirror is one group, totally 2 ^S-1Group.Every group fixedly micro mirror is corresponding with every group of movable micro mirror.Every group fixedly micro mirror be divided into upper and lower two parts, every part is by 2 ^Log2N-s-1Individual mirror composition and neighboring micro are at a distance of p.And the micro mirror of half is in the corresponding movably array region that the micro mirror group is constituted in every part, and is in same horizontal line with corresponding movable micro mirror minute surface; And second half micro mirror is in beyond the movable micro mirror array zone.Micro mirror between every two-stage is all settled and is finished.The rule of its required fixedly micro mirror number is: need 1 group of fixedly micro mirror between the 1st grade and the 2nd grade, be made up of N/2 micro mirror; The 2nd grade and 3rd level need 2 groups of fixedly micro mirrors, form by N/4 micro mirror for every group, because it is overlapping to have the partial fixing micromirror position, the micro mirror of overlapping can be replaced by a two-sided fixing micro mirror, and it is overlapping that the required micro mirror of adjacent set has N/8, so required fixedly micro mirror number is between the 2nd grade and the 3rd level

And the like, the group number of s level and the required fixedly micro mirror of s+1 level is s-1 level and required group of number of s level 2 times, the former in every group the number of micro mirror be among every group of the latter micro mirror number 1/2; Log ₂N-1 level and log ₂Fixedly micro mirror between the N level is the same with situation in front, all is on the center line between the two-stage, and still, the micro mirror of the top in every group is in the horizontal top that the top delegation micro mirror minute surface of corresponding group in the movable micro mirror array constitutes

The place, following micro mirror is in the horizontal below of the micro mirror minute surface formation of delegation bottom of corresponding group in the movable micro mirror array

The place, and the micro mirror of two adjacent groups location overlap replaces with Double sided mirror.Therefore, required fixedly micro mirror number is between s level and the s+1 level

Wherein, the Double sided mirror number is Required fixedly micro mirror adds up to

Wherein, Double sided mirror adds up to

Second specific embodiment

As seen from Figure 4, traditional B enes interconnect architecture is to expand formation at double, promptly for N * N traditional B enes framework, removes the ragged edge two-stage, the network that all intergrades constitute is symmetrical up and down, identical two parts, and every part is the Benes network of N/2 * N/2.The module of each part only is connected with module in this part, and is not connected with module in another part.Each part in these two parts is again to remove the ragged edge two-stage, and the centre is to be made of the Benes network of two N/4 * N/4 up and down.Can correspondingly divide into groups the module in the s level, guarantee that the module of the s-1 level that the module in every group connects does not have identical.Like this, log ₂The N level comprises one group, is labeled as group 1; Log ₂The N-1 level comprises two groups, is labeled as group 1 from top to bottom, group 2; The group number of s level is 1/2 of a s-1 level; Be divided into N/4 group up to the 2nd grade, be labeled as group 1 from top to bottom, group 2 ..., group N/4; The 1st grade is divided into N/2 group, is labeled as group 1 from top to bottom, group 2 ..., group N/2.In each group, module is labeled as 1,2 from top to bottom ...Convenient for the back explanation, in whole interconnection architecture, each switch module comes mark, array (s-level number, the group number in this level of g-, the module No. during m should organize) with the array that three numbers constitute.As shown in Figure 4, because discussed the front, guarantee Benes interconnection principle, each switch module should carry out position rearrangement reaction according to the reordering rule of shuffling that proposes.In the 4th, will be described in detail this rule.

As previously mentioned, must put 2 * 2 switch modules ranking again.Log ₂The N level does not need to reset, and module from top to bottom is followed successively by (log ₂N, 1,1), (log ₂N, 1,2) ..., (log ₂N, 1,7), (log ₂N, 1,8).Log ₂In the N-1 level, according to Benes interconnection rule, (log ₂N, 1,1) must with (log ₂N-1,1,1) and (log ₂N-1,2,1) link to each other.When fixedly micro mirror and movable micro mirror are in the position of stipulating previously, (log ₂N, 1,1) outgoing beam can arrive log ₂First micro mirror and second micro mirror of counting from top to bottom in the N-1 level are so first micro mirror is corresponding to module (log ₂N-1,1,1), second micro mirror is corresponding to module (log ₂N-1,2,1).Corresponding reordering rule is: the 1st step, and at s level, s=log ₂N-n (n=0,1 ..., log ₂N-1), all modules of this level are pressed module No. from small to large successively corresponding to the micromirror position of arranging from top to bottom in the movable micro mirror array in N * N Benes architecture.The module that module No. is identical has 2 ⁿIndividual, to this 2 ⁿIndividual micromirror position is first position to the 2 from top to bottom ⁿIndividual position is the mirror (or module) of m for all module No.s, group number be 1 mirror (s, 1, m) be placed on first position, group number be 2 mirror (s, 2, m) be placed on its at a distance of 2 ^N-1The 2nd of p ^N-1+ 1 position.The 2nd step was a benchmark with this two sides mirror, mirror (s, 1, m) below with its at a distance of 2 ^N-2The 2nd of p ^N-2+ 1 position place mirror (s, 3, m), mirror (s, 2, m) below with its at a distance of 2 ^N-2The 2nd of p ^N-1+ 2 ^N-2+ 1 position place mirror (s, 4, m).The 3rd step, successively with determined the position (s, 1, m), (s, 2, m), (s, 3, m), (s, 4, m) be as the criterion, in its lower section with its on the position of 2n-3p placement module (s, 5, m), (s, 6, m), (s, 7, m), (s, 8, m).If also have the position of module not determine, just continue.L step, continuing according to these group numbers of having determined the module of positions is benchmark with the position of these modules from small to large successively, in its lower section with its at a distance of 2 ^N-lThe sequence of positions of p is placed the module No. that mirror is determined the relevant position correspondence.Until the s+1 step, the module No. of all micromirror position correspondences is all definite.

Accompanying drawing 5 is that it understands the principle of work of first embodiment and second embodiment specifically according to 16 * 16 low-light electromechanical of the present invention the shuffle structure and the mechanism synoptic diagram of Benes photoswitch.For shuffle Benes positional alignment rule and the layout of each module in total clearly are described.With 16 * 16 Benes two-dimensional micro electromechanical array of photoswitch of shuffling is example, and concrete layout and corresponding module position are as shown in Figure 5.Corresponding with Fig. 4, it comprises 7 grades, is designated as the 1st grade, and the 2nd grade, 3rd level, the 4th grade.Same, connect 1 _{Go into}→ 15 _{Go out}With 2 _{Go into}→ 1 _{Go out}The mechanism of this structure is described.White rectangle is represented movable two-sided micro mirror, and solid-line rectangle is that Double sided mirror is in the D score position, and this moment, photoswitch was " parallel " state; Dashed rectangle represent Double sided mirror be in " on " position, this moment photoswitch be " intersection " state.Grey rectangle is represented fixedly micro mirror.P is the cycle, the distance between two neighboring micros.And the incident angle of supposing light beam is 45 °.For the mechanism of this structure is described, in this structure, set up 1 _{Go into}→ 15 _{Go out}With 2 _{Go into}→ 1 _{Go out}Connect, its situation contrasts with situation in the Benes net traditional in Fig. 4.Set up 1 _{Go into}→ 15 _{Go out}Connect, have successively in these 7 grades, module (1,1,1) is in " intersection " state, and module (2,2,1) and (3,3,1) are in " parallel " state, module (4,3,1), (5,3,2), (6,2,4) and (7,1,8) are in " intersection " state; Set up 2 _{Go into}→ 1 _{Go out}Connect, have successively in these 7 grades, module (1,1,1) is in " intersection " state, and module (s, 1,1) (wherein, s=2,3,4,5,6,7) is in parastate.Obviously, the Benes position rearrangement reaction rule of shuffling is feasible, that is to say, has in the integrated two-dimensional low-light electro-mechanical switches of the Benes position rearrangement reaction rule of shuffling in the two dimension that designs, and Benes interconnection rule and reflection law can satisfy simultaneously.

After resetting the position of optical switch module according to this rule, still can use the control algolithm of traditional B enes structure based on the photoswitch of this project organization, this algorithm is very ripe, and as long as numbers identical switch module in this framework of control corresponding unit controls with in the traditional B enes framework.

From aforementioned discussion as can be known, the length in the path walked of the optical power loss that causes of beam spread and light beam is closely related.The key that reduces the beam spread influence is to shorten its propagation distance in free space.

Fig. 6 is the comparison of the longest path length in two kinds of structures under the different port number, and different port number both results relatively down that drawn.For a traditional N * N two dimension parallel construction switch, shortest path length is p; Longest path length is (2N-1) p.Suppose N=16 and 32, longest path is respectively 31p and 63p.In order to calculate the free space spread length in the Benes two-dimensional micro electro-mechanical switches of shuffling, suppose that two distances between the neighboring micro are p (as Fig. 5), identical with hypothesis in the parallel decussate texture in front.Obtain shuffle path (being equivalent to above-mentioned 2D) in the Benes switch of N * N:

Therefore, for 16 * 16 Benes switches of shuffling, path is 18.44p; And for 32 * 32 switches, path is 38.4p.As seen, shuffle the Benes structure make path with parallel decussate texture reduced in comparison 40%.

And in parallel decussate texture switch, the longest and difference shortest path is (2N-2) p.And in the Benes switch of shuffling, used path is identical.The luminous power difference of walking the light beam loss in different paths mainly is because the order of reflection difference.As previously mentioned, reflection loss is very little, just needs when having only port number huge to consider.Therefore, the Benes switch of shuffling has the repeatability of extraordinary port-to-port.

Now, micromirror size and wafer size in the Benes switch of shuffling are discussed.Fig. 7 (a) is the comparison of w (D) in two kinds of structures under the different port number; Fig. 7 (b) is the comparison of chip area in two kinds of structures under the different port number, has provided the comparative result of different port number.Path in the Benes switch of shuffling (being provided by formula (8)) as 2D substitution formula (2) and (4), and in conjunction with making restriction (p=3r+800um), is obtained: the switch for 16 * 16, w _{Benes shuffles}(D)=71.9um; And for 32 * 32 switch, w _{Benes shuffles}(D)=111.86um.Compare with the result of calculation of parallel cross bar switch in the part 2, the Benes switch of shuffling has reduced greater than 50% the micro mirror radius.

By with the front in identical analytic process, when the micro mirror radius is bigger, obtain following approximate formula:

According to the description of front,

W (D) or micro mirror reduced radius have been described thus 40%, and wafer size has dwindled about 70%.And along with the increase of port number, the amount of saving also increases rapidly.

And, because in the Benes switch arrays of shuffling, the distance between micro mirror strengthens, so, loosened and made restriction (p=3r+800um), and had only the two-stage of ragged edge still to be limited.And, because the requirement to driving and servo control circuit has been loosened in the minimizing of micro mirror sum, heat radiation is become easily, power consumption requires strict no longer so.

Optical cross-connect is a most important network element in the optical-fiber network of future generation, and optical add/drop multiplexer can be regarded as the simplification of optical cross-connect function.Optical cross-connect is finished two major functions, i.e. the cross connect function of optical channel and local road function up and down.Optical cross-connect mainly comprises: cross matrix/switching fabric, driver, backboard and external interface and controller.And the cost of optical cross-connect is mainly determined by the power demand and the physical size of above each several part, power demand and physical size that wherein topmost factor is exactly an optical cross-matrix.The photoswitch of this method design is exactly as the optical cross-matrix in the optical cross-connect, and greatly reduces power attenuation and reduced physical size.

In sum, this method has been designed simple two-dimensional low-light electromechanical optical switch construction and corresponding formation rule, and it has extremely low complexity, is very suitable for as the optical cross-connect in the long-distance netted wavelength division multiplexed optical network.The simplest 2 * 2 two-dimensional micro electromechanical optical switch modules of the photoswitch utilization of this structure (it only uses a Double sided mirror) are basic module, and Benes position rearrangement reaction rule is built array of photoswitch according to shuffling.The photoswitch of this structure has minimum movable micro mirror number.This novel optical switch construction is compared with traditional parallel decussate texture, not only has good optical power loss performance, and has the repeatability energy of better port-to-port.In addition, this structure has reduced required micro mirror radius and wafer size significantly.Therefore, loosened and made restriction, strict driving requirement and servo-control system requirement.

Below only for the specific embodiment of the best of the present invention, though the present invention has illustrated and has described relevant preferred embodiment, but those of ordinary skills are to be understood that, under the prerequisite that does not break away from by the spirit and scope of the present invention defined in the claims, can do various variations to form of the present invention and details.

Claims (5)

1, a kind of method of constructing two-dimensional micro electromechanical photoswitch, it may further comprise the steps: structure N * N photoswitch need be provided with 2log ₂The N-1 level, wherein N is the input/output end port number, intergrade is the 1st grade, with at different levels by the centre to both sides be labeled as the 2nd grade, 3rd level successively, until log ₂The N level, wherein each grade is by lining up making up with N/2 movable micro mirror or the simplest 2 * 2 two-dimensional micro electromechanical optical switch modules of a team from top to bottom, the movable micro mirror minute surface of this N/2 be parallel to each other and per two adjacent movable micro mirrors between distance be p, corresponding movable micro mirror is on the same horizontal line between all levels, constitute matrix structure, and be 2 since the horizontal range between the 1st grade of every two-stage ^Log2N-2P, 2 ^Log2N-3P ..., 2p, p, so just constituted the matrix array of movable micro mirror, on the center line of two adjacent levels, place and maintain static, be parallel to each other and perpendicular to the fixedly micro mirror of substrate.

2, method according to claim 1, wherein said fixedly micro mirror is provided with according to the following steps:

The 1st step, the fixing micro mirror of N/2 of configuration on the center line of the 1st grade and the 2nd inter-stage, it is divided into two parts up and down, every part by N/4 fixedly micro mirror forms and adjacent fixed micro mirror p apart, there is the individual fixedly micro mirror of N/8 to be in the movable micro mirror array zone in every part, and fixedly micro mirror wherein is in same horizontal line with corresponding movable micro mirror, and the individual fixedly micro mirror of all the other N/8 is in beyond the movable micro mirror array zone;

The 2nd step, the fixing micro mirrors of two groups of configurations on the center line between the 2nd grade and 3rd level, every group fixedly the configuration mode of micro mirror is similar with the configuration mode between the 1st grade and the 2nd grade, but every group of required fixedly micro mirror number is N/4, correspondingly, also the movable micro mirror in the 2nd grade and the 3rd level is divided into two groups, every from top to bottom N/4 is one group, allow every group of fixedly corresponding every group of movable micro mirror of micro mirror, two parts about fixedly micro mirror is divided into every group then, every part is made up of the individual fixedly micro mirror of N/8, and the fixedly micro mirror minute surface of every part is parallel to each other and at a distance of p, the fixedly micro mirror of half is on the same horizontal line with movable micro mirror in the corresponding group of movable micro mirror array in every part, and second half is in beyond the movable micro mirror array of the corresponding group zone;

Up to the s step, on the center line between s level and the movable micro mirror of s+1 level, dispose 2 ^S-1Group is micro mirror fixedly, correspondingly, and the movable micro mirror per from top to bottom 2 of s level and s+1 level ^Log2N-sIndividual mirror is one group, totally 2 ^S-1Group, every group fixedly micro mirror is corresponding with every group of movable micro mirror, two parts about every group fixedly micro mirror is divided into, every part is by 2 ^Log2N-s-1Individual mirror composition and adjacent fixed micro mirror are at a distance of p, and the fixedly micro mirror of half is in the corresponding group array region that movable micro mirror constituted in every part, and be in same horizontal line with corresponding movable micro mirror minute surface, and second half fixedly micro mirror be in beyond the movable micro mirror array of the corresponding group zone; Repeat above-mentioned steps, the fixedly micro mirror between every two-stage is all settled and is finished; Wherein, log ₂N-1 and log ₂Between the N level, the fixedly micro mirror of the top in every group is in the horizontal top that the movable micro mirror minute surface of the top delegation of corresponding group in the movable micro mirror array constitutes

The place, following fixedly micro mirror is in the horizontal below of the movable micro mirror minute surface formation of delegation bottom of corresponding group in the movable micro mirror array

The place; And the fixedly micro mirror of two adjacent groups location overlap replaces with Double sided mirror, that is, required fixedly micro mirror number is between s level and the s+1 level

Wherein, the Double sided mirror number is

Therefore, construct a N * N two-dimensional micro electromechanical photoswitch, required fixedly micro mirror adds up to

Wherein, Double sided mirror adds up to

3, method according to claim 1, when described movable micro mirror is 2 * 2 two-dimensional micro electromechanical optical switch modules, its movable micro mirror array and the fixing micro mirror array N * N photoswitch of realizing having the Benes interconnected relationship jointly, but its each movable micromirror position is with respect to the rearrangement of must shuffling of each 2 * 2 optical switch module position in traditional N * N Benes interconnect architecture, now define the module No. of describing each 2 * 2 optical switch modules position in framework in traditional N * N Benes interconnect architecture, this module No. is defined by following method: traditional N * N Benes interconnect architecture is removed the ragged edge two-stage, the network that all intergrades constitute is symmetrical up and down, identical two parts, every part all is Benes networks of N/2 * N/2, and the module of each part only is connected with module in this part, each part in these two parts is again to remove the ragged edge two-stage, the centre is to be made of the Benes network of two N/4 * N/4 up and down, module in the s level is correspondingly divided into groups, the module that guarantees the s-1 level that the module in every group connects does not have identical, like this, log ₂The N level comprises one group, is labeled as group 1; Log ₂The N-1 level comprises two groups, is labeled as group 1, group 2 from top to bottom; The group number of s level is 1/2 of a s-1 level; The 2nd grade is divided into N/4 group, is labeled as group 1 from top to bottom, and group 2 is up to group N/4; The 1st grade is divided into N/2 group, is labeled as group 1 from top to bottom, group 2, up to group N/2, in each group, module is labeled as 1 from top to bottom, 2, and the like, like this, array (the s that each 2 * 2 switch module can constitute with three numbers, g m) comes mark, and s represents level number in this array, g represents the group number in this grade, and m represents the module No. in this group.

4, method according to claim 3, wherein said movable micro mirror is determined by following steps corresponding to the module No. of corresponding module in traditional N * NBenes interconnect architecture:

The 1st step is at s level, s=log ₂N-n, wherein n=(0,1 ..., log ₂N-1), the micromirror position of arranging from top to bottom in movable this level of micro mirror array is pressed the module No. that the m value is arranged from small to large corresponding to this level in the traditional B enes interconnect architecture successively, and the module No. that the m value is identical has 2 ⁿIndividual, 2 of correspondence ⁿIndividual micromirror position is first position to the 2 from top to bottom ⁿIndividual position, module No. (s, 1, m) corresponding to the micro mirror that is in first position, module No. (s, 2, m) corresponding to be in first position at a distance of 2 ^N-1The 2nd of p ^N-1The micro mirror of+1 position;

The 2nd step was a benchmark with this two sides micro mirror, micro mirror (s, 1, m) below with its at a distance of 2 ^N-2The 2nd of p ^N-2The micro mirror of+1 position corresponding to module No. (s, 3, m); Micro mirror (s, 2, m) below with its at a distance of 2 ^N-2The 2nd of p ^N-1+ 2 ^N-2The micro mirror of+1 position corresponding to module No. (s, 4, m); The 3rd step, successively with determined the position (s, 1, m), (s, 2, m), (s, 3, m), (s, 4, m) be benchmark, in its lower section with its apart 2 ^N-3The micro mirror of the position of p corresponding to module No. (s, 5, m), (s, 6, m), (s, 7, m), (s, 8, m);

If also have the module No. of micro mirror not determine, just continue; Q (step of 1≤q≤s+1), continue according to these the group number of the micro mirror of determination module number be benchmark with the position of these modules successively from small to large, in its lower section with its at a distance of 2 ^N-lThe micro mirror corresponding group number m of the order module No. from small to large of the position of p, wherein l represents the l step;

Until the s+1 step, the module No. of all micromirror position correspondences is all definite.

5, a kind of optical cross-connect that is used for long-distance netted wavelength division multiplexed optical network, it has the two-dimensional micro electromechanical photoswitch of basis as arbitrary described method construct of claim 1～4.

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