JPH05188405A - Method for controlling polarization control type spatial optical switch - Google Patents

Abstract

PURPOSE:To switch optical paths dispersedly by changing over control signal light superposed on information signal light with multistage spatial optical switch. CONSTITUTION:A polarized light separator 1 separates the polarized light of incident light and a polarized light controller 21 controls the polarization direction and outputs the light; and a 1st reflection block 5 which has a lambda/4 plate 3 and an optical path changing element 4 shifts the incident light by an inherent quantity and reflects it and a 2nd reflection block 8 which has a lambda/4 plate 6 and a reflecting mirror 7 reflects the incident light to the same optical path and changes the optical path of the input light of laterally polarized light to a vertical direction as it is according to the separating direction of the polarized light separator 1 by controlling the polarization direction of the polarized light controller 21 to output the light. In this case, the information signal light and the control signal light of the polarized light controller are superposed on the input light, a part of the control signal light is transmitted through the optical path changing element and reflecting mirror 7, and the transmitted control signal light is detected by photodetectors 9 and 10 arranged at the back. Then the light is supplied as control information to a polarized light controller 22 in a succeeding state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a spatial light switch, and more particularly to a polarization control type spatial light in which a spatial light switch controls polarization, polarization separation by a polarization beam splitter (PBS), and an optical path change by a prism. The present invention relates to a switch control method.

In order to cope with high-speed and large-capacity in communication / information processing systems, it is considered to connect and switch signals by using light, particularly between boards, between chips, between waveguides, and fibers. The development of a polarization control type spatial optical switch for variably connecting one-dimensional or two-dimensional spatially multiplexed optical signals in a space, etc. is under way.

In such a polarization control type spatial optical switch, polarization control of each stage in the case where a multi-input and multi-output spatial optical switch is constructed by connecting a single-stage spatial optical switch to a plurality of cascades It is demanded that the optical path can be easily switched by setting the device, and that self-routing and dispersion processing of optical signals can be realized.

[0004]

2. Description of the Related Art As a conventional method for controlling a spatial optical switch, a computer is applied by applying an address of an input node to which an optical signal is input and an address of a desired output node for the optical signal to the control rule of the optical switch. The method of determining the state of the polarization controller of all nodes of all stages by simulating an optical switch above is commonly used.

However, a technique for realizing a multi-input, multi-output spatial optical switch by connecting a single-stage spatial optical switch to a multi-stage cascade to form a multi-stage optical switch has not been known. ..

[0006]

When an optical switch having a one-stage configuration is connected to a plurality of stages to form a multi-stage spatial optical switch and an optical switch capable of switching between multiple inputs and multiple outputs is to be realized. It is necessary to control the optical switches of all the stages forming the multi-stage spatial optical switch.

In this case, as a control rule for switching the optical switch, it is necessary to determine the destination of the optical signal in each optical switch stage by performing the addressing information of the optical signal itself. Must dispersively control individual polarization controllers in each stage and node. In other words, the state of each polarization controller must be determined by the addressing information of the optical signal input to each polarization controller.

For that purpose, it is necessary to monitor the optical signal in all the optical switch stages, extract the control signal contained in the optical signal, and convert it into the control information of the polarization controller. However, heretofore, such a control method has not been known at all.

The present invention is intended to solve such a problem of the prior art, and in a spatial optical switch having a multistage structure, an optical signal is monitored at each optical switch stage and control included in the optical signal is performed. It is intended to extract a signal and convert it into control information of a polarization controller, and control of a polarization control type spatial optical switch including a control signal multiplexing method and a control signal monitoring method therefor. It is intended to provide a scheme.

[0010]

FIG. 1 shows the basic configuration of the present invention. The present invention is directed to a polarization separator 1 that allows one polarization component of incident light to pass therethrough and reflects the other polarization component orthogonal to this polarization component for output, and a polarization separator 1.
As the polarization direction of the input light IN according to the arrangement to external control on the incident light side of, or between the polarization controller 2 ₁ orthogonal direction is changed to output this, the spindle is the polarization direction and 45 ° of the incident light As described above, the λ / 4 plate 3 arranged perpendicularly to the reflected light of the polarization separator 1 and the incident light from the λ / 4 plate 3 are provided on the opposite side with respect to the central axis by an optical path specific to the element. A first reflection block 5 composed of an optical path changing element 4 which shifts and reflects the light, and λ arranged perpendicular to the light passing through the polarization separator 1 so that the optical axis forms an angle of 45 ° with the polarization direction of the incident light. / 4
A plate 6, and a second reflection block 8 consisting of the reflecting mirror 7 for reflecting the same optical path the incident light from lambda / 4 plate 6, under the control of the polarization direction in the polarization controller 2 _1, polarization separation A spatial light switch for generating output light OUT by changing the optical path of vertically polarized light or horizontally polarized input light IN as it is or in the direction perpendicular to its traveling direction according to the separation direction of the device 1, or a first reflection block. 5 and space optical switch comprising interchanged and the second reflection block 8, or in space optical switch that allows multiple optical inputs to a polarization controller 2 ₁ and the optical path changing element 4 in an array, the input light iN In the above, the information signal light and the control signal light of the polarization controller having the same polarization as that of the information signal light are superposed, and at the same time, the optical path changing element 4 and the reflecting mirror 7 have a characteristic that a part of the control signal light can be transmitted. Control By detecting the signal light by the photodetectors 9 and 10 arranged behind the optical path changing element 4 and the reflecting mirror 7, regardless of the polarization direction of the input light IN, or light of different polarization directions is simultaneously detected. Even if input, the control signal is detected and the polarization controller 2 ₂ at the next stage is detected.
The control information can be given to the.

In this case, according to the present invention, the control signal is superimposed on the information signal in a time division manner, and a part of the light is transmitted through the optical path changing element 4 or the reflecting mirror 7, and the remaining light is reflected. When a part of the input light passes through the optical path changing element 4 or the reflecting mirror 7, the photodetector 9 or 10 detects the control information in the input light.

In this case, the present invention also provides an optical path changing element 4
Alternatively, the reflection part of the reflection mirror 7 may have a wavelength filter effect, and the information signal light of the wavelength reflected by the reflection part and the control signal light of the wavelength part of which is transmitted through the reflection part are wavelength-multiplexed input. The control information is detected by the photodetectors 9 and 10 from the light IN.

Further, in the present invention, in this case, the wavelength difference between the information signal light and the control signal light is (2mπ + π / 2) between the ordinary light and the extraordinary light generated at the λ / 4 plates 3 and 6. ) The radians (m is an integer) are used to prevent the difference in the characteristics of the λ / 4 plate due to the difference in the wavelength between the information signal light and the control signal light.

In this case, the present invention is also applicable to any one of the above.
It consists of multiple spatial light switches connected in multiple stages.
Et al (2^N2 sequentially numbered by the integer of -1)
^NHas 2 inputs and 2 outputs^N-1, ..., 2^Nn，… ，
Two⁰Channel shift (n = 1, 2, ..., N)
Two^NStructured by optical switching stage for general routing of node
Optical switch network made, or one or more stages
Optical switch configured by adding an optical switch stage for bypassing
Swap the nets, or the order of the optical switch stages in these cases
In the general routing stage of the optical switch network,
The address of the output node that should be reached
Bit binary serial signal starts with “1” synchronization at any time
Bit B for another_disAs an N + 1 bit signal with
Control signal S given by_cntAnd the control signal S at each stage_cnt
Extracted from the control signal S_cntAbout the same as the width of one pulse
Has a pulse width of 2^NnIn the shift stage, at the nth bit
Sync signal S for synchronization_synAnd 2^NnIn the shift stage
Expressed by the nth bit number in binary notation of node number
Signal S indicating the number of stages and the state of the node_nodea
The optical path changing element 4 in the optical switch stage is
If it is on the output side of the horizontally polarized light, it becomes "0", and the vertically polarized light
The optical path changing element 4 which becomes "1" when the light is on the side of emitting light
Signal S indicating the position of_opsAnd the horizontal polarization.
To prioritize the incident light in the
Issue S_cntAnd signal S_nodeAnd signal S_opsExclusive logic of denial of
Sync signal S of sum and horizontal polarization_synAnd product) and (vertical polarization control)
Signal S_{cn t}And signal S_nodeDenial and signal S_opsDenial of
Alternate OR and horizontal polarization sync signal S _synProduct of the denial of) and
When the result is “0”, the polarization of the incident light is
Is output as is, and when the result is "1", the polarization of the incident light
Of the next polarization controller array so that
Controls the state of the polarization controller at the numbered node. Vertical bias
To prioritize incident light consisting of light,
Polarization control signal S_{cn t}And signal S_nodeAnd signal S_opsDenial of
Of the exclusive OR of S and the vertically polarized sync signal S_synWith the denial of
Product) and (vertically polarized control signal S_cntAnd signal S_nodeWith the denial of
Signal S_opsExclusive-OR of Negative and vertical polarization sync signal S
_synAnd the result is “0”,
Output the polarized light of the incident light as it is, and when the result is "1",
Polarization control of the next stage to rotate the polarization of incident light by 90 °
The state of the polarization controller of the node with the same number in the optical array
Or control signal S_cnt,Signal S_node,Sync signal S_sys,
Signal S_opsFor control information consisting of
It is a logical process that brings about such an effect.

The present invention also relates to the polarization control type spatial light switch described above.
In the control method of the switch, the signal S_{no de}Value of each step,
It is fixed by the mode and vertically polarized light is emitted from the polarization separator 1.
In the configuration in which the optical path changing element 4 is arranged in the direction
When prioritizing the horizontally polarized incident light at that stage,
Is the signal S_nodeIs "0", (control signal for horizontal polarization
Issue S_cntAnd horizontally polarized sync signal S_synProduct of) and (vertical polarization
Control signal S_cntNegative and horizontal polarization sync signal S_synNo
Constant product) and the result is “0”, enter
The polarization of the incident light is unchanged, and when it is “1”, the polarization of the incident light is changed.
Signal S to rotate 90 °_nodeIs in the place of "1"
Is (transversely polarized control signal S_cntDenial and horizontal polarization sync signal
Issue S_synProduct of) and (vertical polarization control signal S_cntAnd horizontal polarization
Sync signal S _synAnd the product of
When the result is "0", the polarization of the incident light is unchanged and the
When the polarization of the incident light is rotated by 90 °,
State of the polarization controller of the node with the same number in the polarization controller array
To control. Or vertically polarized light is emitted from the polarization separator 1.
In the configuration in which the optical path changing element 4 is arranged in the direction
When prioritizing the vertically polarized incident light in that stage,
Is the signal S_nodeIs "0", (control signal for horizontal polarization
Issue S_cntAnd vertically polarized sync signal S_synProduct of the denial of) and
(Vertical polarization control signal S_cntOf negative and vertically polarized sync signal S
_synAnd the product) and the result is “0”,
The polarization of the incident light is unchanged, and when it is "1", the polarization of the incident light
Signal S to rotate_nodeIs "1"
Then, (horizontal polarization control signal S_cntOf negative and vertical polarization
Signal S_synAnd the vertical polarization control signal S_cnt
And vertically polarized sync signal S_synAnd the product of
When the result is "0", the polarization of the incident light is unchanged and "1"
In the case of, the polarized light of the incident light should be rotated by 90 degrees.
Of the same numbered nodes in the polarization controller array of
Control the state. Or the horizontally polarized light is emitted from the polarization separator 1.
In the configuration in which the optical path changing element 4 is arranged in the direction of irradiation.
And prioritize the horizontally polarized incident light at that stage.
The signal S_nodeIs "1", (transverse polarization control
Signal S_cntAnd horizontally polarized sync signal S_synProduct) and (vertical bias
Light control signal S_cntNegative and horizontal polarization sync signal S_synof
When the result is “0”,
The polarization of the incident light is unchanged, and when it is "1", the polarization of the incident light
Signal S to rotate _nodeIs "0"
Then, (horizontal polarization control signal S_cntOf negative and vertical polarization
Signal S_synProduct of) and (vertical polarization control signal S_cntAnd lateral
Optical synchronization signal S_synAnd the product of the
When the result is "0", the polarization of the incident light is unchanged and "1"
In the case of, the polarized light of the incident light should be rotated by 90 degrees.
Of the same numbered nodes in the polarization controller array of
Control the state. Or the horizontally polarized light is emitted from the polarization separator 1.
In the configuration in which the optical path changing element 4 is arranged in the direction of irradiation.
And prioritize vertically polarized incident light at that stage.
The signal S_nodeIs "1", (transverse polarization control
Signal S_cntAnd vertically polarized sync signal S_synProduct of the denial of) and
(Vertical polarization control signal S_cntOf negative and vertically polarized sync signal S
_synAnd the product) and the result is “0”,
The polarization of the incident light is unchanged, and when it is "1", the polarization of the incident light
Signal S to rotate_nodeIs "0"
Then, (horizontal polarization control signal S_cntOf negative and vertical polarization
Signal S_synAnd the vertical polarization control signal S _cnt
And vertically polarized sync signal S_synAnd the product of
When the result is "0", the polarization of the incident light is unchanged and "1"
In the case of, the polarization of the incident light is rotated by 90 °
Of the same numbered nodes in the polarization controller array of
It controls the state.

Further, the present invention is to control these polarization control type spatial optical switches by uniquely controlling the value of the signal S _node in the detour optical switch stage.

In the present invention, in these polarization control type spatial optical switch control methods, the control signal S _cnt is repeated several times by arranging a specific bit B _dis and a bit required for control at each stage. And control signal S
_The sync signal S _syn created from _{cnt is} created so as to be synchronized with that bit, and the repetition interval is defined as the time τ that is the sum of the operation speed of the control signal processing circuit and the operation speed of the polarization controller.
By the above, the control signal detected in the next stage is prevented from entering the next stage before being switched to the optical path which should travel.

According to the present invention, in these polarization control type spatial light switch control methods, the control signal S _{cnt is set} to a time interval of τ or more, which is the sum of the operation speed of the control signal processing circuit and the operation speed of the polarization controller. After the optical switch is repeated several times or more, the information signal light is transmitted to eliminate the influence of the operating speed of the control signal processing circuit and the operating speed of the polarization controller. ..

Further, according to the present invention, in these polarization control type spatial optical switch control methods, an optical buffer is inserted immediately before the polarization controller at each stage, and the operating speed of the control signal processing circuit and the operating speed of the polarization controller are increased. By performing buffering for a time equal to or longer than the combined time τ, the influences of the operating speed of the control signal processing circuit and the operating speed of the polarization controller are removed.

[0020]

2 is a diagram showing the basic principle of a polarization control type spatial optical switch which is the basis of the present invention, and FIG. 3 is a diagram showing a multi-input multi-stage spatial optical switch which is the basis of the present invention.

First, the basic principle of the polarization control type spatial optical switch which is the basis of the present invention will be described. In FIG. 2, reference numeral 1 denotes a polarization separator which transmits one polarization component of incident light and reflects a polarization component orthogonal to the polarization component for output, and 2 denotes the polarization direction of the input light as it is or orthogonally according to external control. It is a polarization controller that changes the direction and outputs. Reference numeral 3 denotes a λ / 4 plate for the used wavelength λ, which is arranged perpendicularly to the reflected light of the polarization separator 1 so that the main axis forms 45 ° with the polarization direction of the incident light. Reference numeral 4 denotes an optical path changing element that reflects the incident light beam from the λ / 4 plate 3 to an optical path that is shifted to the opposite side with respect to the central axis by an amount peculiar to the element, and 5 is a first optical path changing element that reflects the incident light. The reflection block 6 is a λ / 4 plate for the used wavelength λ, and is arranged perpendicular to the light passing through the polarization separator 1 so that the principal axis forms 45 ° with the polarization direction of the incident light.
Reference numeral 7 is a reflecting mirror that reflects the incident light from the λ / 4 plate 6 in the same optical path, and 8 is a second reflection block that reflects the incident light.

FIG. 3 shows a multi-input multi-stage spatial optical switch which is the basis of the present invention, in which the polarization control type spatial optical switch shown in FIG. 2 is connected in multiple stages in a cascade. have.

The operating principle of the spatial light switch shown in FIGS. 2 and 3 is as follows. That is, the polarization state of light that is incident as a single polarized light in the horizontal direction or the vertical direction is converted into polarized light that passes through the polarization separator 1 by the polarization controller 2 arranged immediately in front of the polarization separator 1. The optical path is selected by determining whether the polarized light reflected by the container 1 is used.

When the light is reflected by the reflecting block 5 or 8 and returns, the polarized light is rotated 90 ° by passing through the λ / 4 plate 3 or 6 twice, and the laterally polarized light becomes longitudinally polarized light.
Since the vertically polarized light is changed to the horizontally polarized light, the relationship between the light passing through the polarization separator 1 and the reflected light is reversed, and the light that has passed through the two optical paths is combined, and the incident direction is Emit in the opposite direction.

At this time, since the optical path changing element 4 inserted in the optical path on the side passing through the reflection block 5 shifts the optical path, the polarization controller 2 controls the polarization of the incident light so that Space switching can be performed.

In this case, the shift amount of light depends only on the shape and size of the optical path changing element 4 and does not depend on the incident position of light, so that it is possible to handle a plurality of light inputs and all light is input. Can be emitted in the same direction. Therefore, it is also possible to connect the spatial light switches shown in FIG. 2 in a multistage cascade to form a multi-input multistage spatial light switch as shown in FIG.

Using such a spatial light switch as shown in FIG.
As shown in, when a Banyan network type multi-input, multi-stage optical switch is configured, the state of the polarization controller at each stage and node is such that the input light incident on it finally arrives. It is determined by the value of the address to be used. Therefore, control information light having the address value as information is superimposed on the information signal light, the control signal is extracted for each optical switch stage, and the state of the polarization controller of each node is determined by the information. Will be required. At this time, the light having the information signal and the light having the control signal must reach the final node through the same optical path.

In addition to the configuration shown in FIG. 2, the principle configuration of the present invention shown in FIG. 1 further includes a photodetector 9 arranged at the output side of the first reflection block, and And a photodetector 10 arranged on the output side of the second reflection block. Further, the polarization controller 2 ₂ on the input side of the next stage is shown with respect to the polarization controller 2 ₁ on the input side.

The information signal light control signal is superimposed, after being controlled polarization by the polarization controller 2 _1, depending on its polarization direction, it passes through the polarized light separator 1, or is reflected, the optical path changing element 4 or incident on the reflecting mirror 7. At this time, the characteristics of the optical path changing element 4 and the reflecting mirror 7 are set such that a part of the control signal light can pass therethrough.
By arranging the photodetectors 9 and 10 behind the reflecting mirror 7, it becomes possible to detect the control signal of the polarization controller 2 _{2 in} the next stage.

In this optical switch, there is a case where light of vertical and horizontal polarization directions is simultaneously incident on one node, that is, a single element polarization controller. One of the features of this optical switch is that Thus, even if the vertically polarized light and the horizontally polarized light are simultaneously incident, they can be separated without being mixed. By using this monitor method, even if light of vertical and horizontal polarization directions is simultaneously incident on one node, these two input lights can be simultaneously monitored and control information can be independently extracted.

A method of superimposing a control signal on the information signal light,
And as a method for extracting the signal, the following two methods can be adopted.

As one method, a control signal is superimposed on the information signal in a time division manner, and the optical path changing element 4 and the reflecting portion of the reflecting mirror 7 are constituted by a beam splitter. This allows a portion of the input light to pass through and be monitored by the photodetector 9 or 10 to extract a control signal therefrom.

As another method, the information signal and the control signal are superposed by multiplexing the information signal light and the control signal light having the same polarization direction but different wavelengths, and the optical path changing element 4 and the reflecting mirror. The reflection part 7 is made of a material having a wavelength filter effect, such as a dielectric multilayer film. Then, the information signal light is set to have a wavelength that is reflected by the reflecting portion, and the control signal light is set to have a wavelength that is partially transmitted through the reflecting portion and the rest is reflected. Thereby, the control signal light is transmitted to the photodetector 9,
The control signal can be extracted by monitoring at 10.

In this case, two wavelengths are used, but since the characteristics of the λ / 4 plate depend on the wavelength, the two wavelengths used should both satisfy the characteristics of the λ / 4 plate. You have to choose. In this case, there are the following two methods for selecting the wavelength.

As one method, a λ / 4 plate having a wide band property is used, and the wavelength to be used is selected so that the characteristics of the λ / 4 plate are satisfied.

As another method, in the λ / 4 plate, the phase difference between the ordinary light and the extraordinary light generated there is (2mπ + π /
2) When it is radian (m is an integer), it is in the optimum state. Therefore, select the two wavelengths to be used so that this condition is satisfied, so that the characteristics of the λ / 4 plate are satisfied. You can

FIG. 4 is a diagram for explaining a method of realizing an optical switch control law in a multi-input multi-stage spatial optical switch, showing an application of the above-mentioned control signal monitoring system to the multi-input multi-stage spatial optical switch, and 8 inputs 3 The case of a multi-stage spatial optical switch is illustrated. The same components as those in FIG. 1 are designated by the same reference numerals, and 11 is a beam splitter arranged in front of the first-stage polarization controller or a polarizing beam splitter also serving as a polarizer. 5 shows an equivalent circuit of the spatial light switch of FIG.

This multi-input optical switch is from 0 to (2 ^N-
2 ^N-1 , ..., Determined by the structure of the optical path changing element at each stage of the optical switch consisting of N stages, for 2 ^N optical inputs whose address numbers are given in order by the integers of 1).
2 ^Nn, ..., 2 ⁰ channels (n = 1,2, ..., N ) performs a shift, and is configured by (2 ^N -1) General routing optical switch stage of the node N stages.

Switching control of this optical switch is performed at each stage,
It is controlled by the polarization controller of each node.
The control information is the control signal of the input light reaching it.
Extracted by ingredients. The control information given is
Set the address value of the output section where the signal light is going to reach
It is expressed as a decimal number. In the equivalent circuit of FIG. 5, 2
^NnThe control information of the channel shift stage is the binary number.
It is represented by the value of the nth bit from the beginning. When it is "0", it is low
On the dress side, on the high address side when "1", the optical path
Is executed.

When this control rule is applied to the optical switch shown in FIG. 4, the control rule is that the polarization state of the incident light, the address of the node, and the optical path changing element 4 determines whether the polarization separator 1 is arranged vertically or horizontally. It changes depending on whether or not it is arranged on the side where the light in the polarization direction is emitted.

These pieces of information are represented by parameters consisting of the following signals. (1) Convert the address of the output node that should be reached to a binary number, and
A control signal S _cnt (2) given as a binary serial signal of bits has a pulse width similar to that of one pulse of the control signal, and is synchronized so as to be synchronized with the nth bit in a 2 ^Nn shift stage. Signal S _syn (3) 2 ^Nn A signal S _node (4) which indicates the number of stages and the state (number) of the node, which is represented by the number of the n-th bit in the binary notation of the node number at the shift stage The optical path changing element 4 in the switch stage has a value of "0" when it is on the side where the horizontally polarized light of the polarization separator 1 is emitted, and has a value of "1" when it is on the side where the vertically polarized light is emitted. , A signal S _ops representing the position of the optical path changing element

In this case, the control rule of the polarization controller at each node of the 2 ^Nn shift optical switch stage is as follows. SC = PS xor S _node xor S _ops ^* xor S _cnt (n) (1) where S _cnt (n) is the value of the n-th bit of S _cnt , and PS had its control signal. The polarization state of the input light is shown. PS is “0” if it is laterally polarized light,
If it is vertically polarized light, it becomes "1". Further, S _ops ^* represents a negative signal of S _ops . The same applies to other cases.

When this optical switch is constructed as shown in FIG. 4, there are cases in which signal light of two vertical and horizontal polarization directions is simultaneously incident on one node. Even in this case, the two signal lights are not mixed but separated and are incident on the next stage. However, in that case, it is necessary to set a standard as to which signal light control signal is dominant. As a method for that purpose, the following method is adopted.

First, a bit B _dis for identifying the presence / absence of a signal is added to the head of an N-bit control signal to obtain N + 1.
It is a time-series signal of bits. This bit B _dis is always in the “1” (on) state, and when this bit is detected by the horizontally polarized light monitor, it indicates that the horizontally polarized input light is incident on the node at the next stage. When this bit is detected on the polarization monitor, it indicates that vertically polarized input light is incident on the next node, and when this bit is detected on both horizontal polarization and vertical polarization monitors, it is It is assumed that the polarized input light and the vertically polarized input light are simultaneously incident on the next-stage node.

Next, what is to be the priority condition is determined. This shall be unified in all optical switch stages and nodes. The conditions include the polarization direction of the incident light and whether the optical path when entering the next stage is a straight traveling mode or a switching mode.Both of them are finally converted into the conditions related to the polarization direction of the incident light. To be done. In other words, it is only necessary to determine which polarization direction the incoming signal should be prioritized in each optical switch stage.

Once the priority of the polarization direction is determined, it is necessary to determine the realization means for performing this processing next. Below, assuming an optical switch stage of 2 ^Nn shift,
This means will be described.

First, the B _dis bit is extracted from the detected control signal and delayed by n bits to obtain the control signal S.
A synchronization signal S _syn synchronized with _cnt (n) is created. In order to always use the synchronization signal S _syn to determine the state of the polarization controller with the control information having the higher priority, the following processing may be performed. First, a case will be described as an example in which light in the horizontal polarization direction is prioritized.

In this case, the process for determining the state of the polarization controller is as follows: SC = (S _syn (p) and SC (p)) or (S _syn (p) ^* and SC (s)) (2) where , SC (p), SC (s) are the control information extracted from the control signal of the light to be incident on the next stage in the laterally polarized light (p) and the vertically polarized light (s), respectively, using the equation (1). S _syn (p) is the bit B extracted from the control signal of the light that is going to enter the next stage in the laterally polarized light (p).
It is a sync signal created from _dis .

Substituting equation (1) into equation (2), SC = (S _syn (p) and (S _node xor S _cnt (n, p) xor S _ops ^* )) or (S _syn (p) ^{* _{and (S node * xor S cnt}} (n, s) xor S ops *)) ... it is (3).

When priority is given to light in the vertical polarization direction, SC = (S _syn (s) ^* and (S _node xor S _cnt (n, p) xor S _ops ^* )) or ( S _syn (s) and (S _node ^* xor S _cnt (n, s) xor S _ops ^* )) (3) ′.

In the equation (3), when _Sops is "0",
That is, when the optical path polarization element 4 is on the side from which the laterally polarized light of the polarization separator 1 is emitted, SC = (S _syn (p) and (S _node ^* xor _Scnt (n, p))) or (S _syn ( p) ^* and (S _node xor S _cnt (n, s))) (4).

Here, when S _ops is “1”, that is, when the optical path polarization element 4 is on the side where the vertically polarized light of the polarization separator 1 is emitted, SC = (S _syn (p) and (S _node xor S _cnt (n, p))) or (S _syn (p) ^* and (S _node ^* xor S _cnt (n, s))) (5).

From the result of the above logical processing, when the calculated SC value is "0", the polarization controller is set to "a state in which the polarization direction of incident light is emitted as it is", and the SC value is "1". In this case, the polarization controller is set to "a state in which the polarization direction of the incident light is rotated by 90 ° and emitted" to control the state of the polarization controller so that the incident light takes a desired optical path. You can

FIG. 6 shows an example (1) of the control signal processing circuit, and shows the circuit configuration when the processing in the case of the above equation (4) is expressed by a logic circuit. is there.

In the logic process described above, the signal S _node is unique to each node and is "0",
It is possible to fix the state to either "1".
By fixing S _node , two kinds of logic circuits are mixed in one optical switch stage, but the logic circuit itself can be simplified. The logical processing in this case will be described below.

First, in the case of the equation (4), SC = (S _syn (p) and S _cnt (n, p) ^* ) or (S _syn (p) ^* and (S _cnt ) at the position of S _node = 0. (N, s)), and SC = (S _syn (p) and S _cnt (n, p)) or (S _syn (p) ^* and (S _cnt (n, s)) at the position where S _node = 1. ^* )

Next, in the case of the equation (5), SC = (S _syn (p) and S _cnt (n, p)) or (S _syn (p) ^* and (S _cnt ) at the position of S _node = 0. (N, s) ^* ), and SC = (S _syn (p) and S _cnt (n, p) ^* ) or (S _syn (p) ^* and S _cnt (n, s) at the position of S _node = 1. ))

When these items are arranged, S _ops xor
At S _node = 0, SC = (S _syn (p) and S _cnt (n, p) ^* ) or (S _syn (p) ^* and S _cnt (n, s)) (6) S _ops xor S _{At node} = 1, SC = (S _syn (p) and S _cnt (n, p)) or (S _syn (p) ^* and S _cnt (n, s) ^* ) (7) can be summarized. ..

When priority is given to light in the vertical polarization direction, similarly, the optical path changing element 4 is arranged in the direction in which _Sops = 1, that is, the vertically polarized light is emitted from the polarization separator 1. In the configuration, SC = (S _syn (s) ^* and S _cnt (n, p)) or (S _syn (s) and (S _cnt (n, s) ^* )) at S _node = 0, and S _node = 1, SC = (S _syn (s) ^* and S _cnt (n, p) ^* ) or (S _syn (s) and S _cnt (n, s)).

[0060] In the configuration where the light path changing element 4 in the direction S _ops = 0 i.e. the light horizontally polarized light from the polarization separator 1 is emitted is located, at a point _{S node = 1 SC = (S} syn (s ) ^* And S _cnt (n, p)) or (S _syn (s) and (S _cnt (n, s) ^* ), and at the _node where S _node = 0, SC = (S _syn (s) ^* and S _cnt (n, p) ^* ) or (S _syn (s) and S _cnt (n, s)).

When these items are arranged, S _ops xor
SC = (S _syn (s) ^* and S _cnt (n, p)) or (S _syn (s) and S _cnt (n, s) ^* ) (6) 'S _ops xor at S _node = 1 At S _node = 0, SC = (S _syn (s) ^* and S _cnt (n, p) ^* ) or (S _syn (s) and S _cnt (n, s)) (7) ' You can

FIG. 7 shows an example (2) of the control signal processing circuit, in which the processing in the case of the above equations (6) and (7) is expressed by a logic circuit. (A) shows the case where S _node = 0, and (b) shows the case where S _node = 1.

The above is a description of a general optical switch stage control method. Basically, in a banyan network, signal collision occurs, and thus when trying to perform a many-to-many complete cross-connect, an unrealizable combination of input and output occurs due to signal blocking.

This is also the case when a banyan network type network is constructed in a multi-input multi-stage spatial optical switch having the configuration shown in FIG. 4, and it is necessary to avoid it by using some means. However, as one method for that purpose, there is a method of providing a detour optical switch stage in addition to a general optical switch stage.

FIG. 8 illustrates a method of realizing a non-blocking multi-input multi-stage spatial optical switch, illustrating an example of an 8 × 8 optical switch, and adopting a four-stage configuration as shown in the figure. By this, a non-blocking optical switch can be configured.

FIG. 9 shows an equivalent circuit of the 8.times.8 non-block multistage spatial optical switch shown in FIG.
As shown in the figure, the first stage, the third stage, and the fourth stage can be configured by using the above-mentioned general stage control law, but the second stage needs a control law for distributing the load. Is.

The control law in this case can be expressed by the following logical process. SC = PS xor S _ops ^* xor S _cnt (2) (8) Equation (8) can also be described as SC = PS xor 0 xor S _ops ^* xor S _cnt (2) (9) , Which is S in equation (1)
It can be regarded as equivalent to the case of _node = 0.

Therefore, in the logical processing of the above equations (4) to (7), the case where S _node = 0 can be used as it is. The logic circuit in this case is similar to that shown in FIGS.

In these control methods, the operating speeds of the control signal arrangement circuit and the polarization controller are higher than the signal speed.
There is no problem in the case of sufficiently high speed, but if it cannot be said that the speed is sufficiently higher than the signal speed, the control signal will pass before switching to the desired node in the next stage, It becomes impossible to set the polarization controller in the subsequent stages.

Therefore, the pulse width of the control signal S _cnt is
The operating speed of the control signal processing circuit and the operating speed of the polarization controller are combined for a time r or more, and the control signal detected in the next stage is incident on the next stage before being switched to the optical path along which it should travel. Must be prevented.

Other methods for solving such a problem include the following.

One method is to repeat the control signal S _cnt by arranging the bit B _dis and the bits necessary for control at each stage, which are repeated several times. The synchronization signal S _syn generated from the control signal S _cnt is assumed to be generated so as to be synchronized with the bit, and the repetition interval thereof is set to the operation speed of the control signal processing circuit and the operation speed of the polarization controller. The time taken is τ or more.

By doing so, before the control signal detected in the next stage is switched to the optical path to be traveled,
It is possible to prevent the light from entering the next stage.

Another method is to set the control signal S _cnt to the number of stages of the optical switch at a time interval of τ or more, which is the sum of the operation speed of the control signal processing circuit and the operation speed of the polarization controller. Repeatedly over and over,
This is a system in which a signal light carrying information after that is sent.

By doing so, it is possible to eliminate the influence of the operating speed of the control signal processing circuit and the operating speed of the polarization controller, while keeping the control signal having the same pulse width as that of the information signal. ..

Still another method is to insert an optical buffer immediately before the polarization controller of each stage, and for a time equal to or longer than time τ, which is the sum of the operation speed of the control signal processing circuit and the operation speed of the polarization controller, This is a method of buffering.

When this system is adopted, the influence of the operating speed of the control signal processing circuit and the operating speed of the polarization controller can be prevented without modifying the signal itself.

FIG. 10 shows an example of the structure of the control signal. FIG. 10A shows the structure of the control signal S _cnt .
(B) shows an example of superposition of the control signal S _cnt and the information signal.

Now, in the multi-input multi-stage spatial optical switch shown in FIG. 4, it is assumed that the signal obtained by superimposing the control signal and the information signal as shown in FIG. 10B is used as the input light IN. .. First, the control information of the first stage is separated by the beam splitter arranged in front of the polarization controller 2 of the first stage or the polarization beam splitter 11 also serving as a polarizer, and arranged on the opposite side of the polarization controller 2. The control signal light detected by the photodetector array 10 is extracted by the equation (4) or (5), and the state of the first-stage polarization controller array 2 is determined by this control information. The input light converted into a desired polarization direction depending on the state of the polarization controller array 2 is
It is transmitted by the polarization separator 1 or reflected by it.

After that, the input light incident on the optical path changing element 4 or the reflecting mirror 7 is emitted to the next stage with the optical path as it is or after the optical path is changed. At that time, a part of the light passes through the respective reflection portions and is incident on the photodetector array 9 or 10 arranged behind, and the control signal component is extracted. The state of the second-stage polarization controller 2 is determined by the control information determined by the equation (4) or (5) by the extracted control signal component.

In this way, the state of the polarization controller of each stage is determined by determining the state of the polarization controller of the next stage based on the control information detected and extracted by the photodetector array of each stage. , The optical path of the input light can be set. The control of the detour stage is determined according to the equation (9).

[0082]

EXAMPLE FIG. 11 shows an example of the present invention, illustrating a case of an 8 × 8 non-blocking polarization control type spatial optical switch, and the same elements as those in FIG. 4 are indicated by the same numbers. ing. Reference numeral 13 is a beam separator, 14 is a photodetector array, 15 is a polarization controller, 16 is a polarization separator, and 17
Is an optical path changing element, 18 is a photodetector array, and 19 is a polarization controller. FIG. 12 shows an example of control information of the input light D (1, i) in the embodiment of FIG. Further, FIG. 13 shows an equivalent circuit of the optical path switching control in the embodiment of FIG.

Now, in FIG. 11, (0, 1, 2,
3, 4, 5, 6, 7) input light D (1, i) incident from the input node D (5, j)
(0,6,3,5,7,1,2,4). In FIG. 12, the control information of the input light D (1, i) in this case is illustrated.

In FIG. 11, the signal S _ops becomes 1,0,1,0 in the first to fourth stages, respectively. As a condition of the priority, if the light incident on the node in the straight traveling mode is prioritized, this condition can be replaced with the polarization state of the light incident on each node. The condition is that the light incident on the photodetector of the eye in the horizontal, vertical, horizontal, and vertical polarization directions is given priority. Of these, the input light D (1,1) will be described as an example.

The destination node of the input light D (1,1) is D
It is (5, 6), and when this address is expressed in binary, it is 11
It becomes 0. The control information based on this is shown in (b) in FIG.

Hereinafter, in the optical switch shown in FIG.
A case where the control information shown in 2 (b) is applied will be described.

Eight-channel input light is incident from an incident portion formed of an array of 8-channel light sources. However, the initial state of the polarization of the incident light is assumed to be in the lateral direction (p). Of these, a part of the light incident from D (1,1) is separated by the beam separator 13, and the light detector array 1
Incident on 4.

The signals detected by the photodetector array 14 are
As shown in FIG. 12B, the bit B _dis is extracted from this signal and delayed by 1 bit to generate the synchronization signal S _syn for the first-stage polarization controller array 15.

In the first-stage polarization controller array 15, the light incident in the lateral direction is prioritized, and the signal S _ops =
It is 1. In addition, the node in this case is 1, and when converted to a binary number, it is 001, so the signal S _node = 0 and S
_{Since ops} xor S _node = 1, the control rule in this case is that SC = (S _syn (p) and S _cnt (1, p)) or (S _syn (p) ^* and S _cnt from equation (7). (1, s) ^* ).

The polarization state of the incident light on the first stage is in the lateral direction (p).
Therefore, the bit B obtained by the photodetector array 14
_{Since the} synchronization signal S _syn obtained from _dis is S _syn (p) and S _syn (p) is 1, the above equation is SC = S _cnt (1, p) = 1 and D (1, The state of the polarization controller 15 on which the light emitted from 1) is incident is "on".

Therefore, the incident light is vertically polarized by the polarization controller 15 in the first stage, reflected by the polarization separator 16, and then the optical path is shifted by four channels by the optical path changing element 17 to become horizontal polarized light. The light is transmitted through the polarization separator 16 and is incident on D (2,5) in the next stage.

At this time, a part of the input light that has passed through the reflecting portion of the optical path changing element 17 is input to the photodetector array 18. A control signal is extracted from the signal detected by the light input to the photodetector array 18 by the same method as described above, and the control information of the polarization controller 19 in the next stage is created.

By performing control in each stage in this way, the input light propagates from D (1,1) to D (5,6) as shown by the solid line in FIG. The equivalent wiring in this case is as shown in FIG.

FIG. 14 collectively shows the nodes through which the incident light passes in each stage and the parameters in each node. However, the second stage is a detour stage, and therefore the signal S _node is 0 at all nodes.

According to the parameters shown in FIG. 14, 2
The control rules for the fourth to fourth steps are defined as follows. (1) Second stage SC = (S _syn (s) ^* and S _cnt (2, p) ^* ) or (S _syn (s) and S _cnt (2, s)) (2) Third stage SC = ( S _syn (p) and S _cnt (2, p) ^* ) or (S _syn (p) ^* and S _cnt (2, s)) (3) Fourth stage SC = (S _syn (s) ^* and S _cnt (3, p)) or (S _syn (s) and S _cnt (3, s) ^* )

In the first, second, and fourth rows, D (1,1)
The control information is determined by the control signal S _cnt of the input light from _D.sub.c , but in the third stage, the input light from D (1,7) is D (1,1) as shown in FIG. ) Collide with the input light from.

Applying this to the control rule of the third stage, D
The control signal S _cnt of the input light from (1, 7) has priority, and the state of the third-stage polarization controller is determined by this control information. FIG. 14 also shows the states of the polarization controllers at the nodes to which the input light from D (1,1) is incident, in each stage determined by these control rules.

FIG. 15 shows the optical paths on the optical switch for all the input light in the embodiment of FIG. 11, showing an embodiment in the case of an 8 × 8 optical switch.
The same items as in 1 are indicated by the same numbers. Also,
FIG. 16 shows equivalent wiring for the example of FIG.

[0099]

As described above, according to the present invention, in the multi-input multi-stage spatial optical switch, the polarization controller of each stage can be easily set, and the self-routing optical switch can be controlled by the dispersion control. Can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention.

FIG. 2 is a diagram showing a basic principle of a polarization control type spatial light switch which is a basis of the present invention.

FIG. 3 is a diagram showing a multi-input multi-stage spatial optical switch which is the basis of the present invention.

FIG. 4 is a diagram illustrating a method of realizing an optical switch control law in a multi-input multi-stage spatial optical switch.

5 is a diagram showing an equivalent circuit of the spatial light switch of FIG.

FIG. 6 is a diagram showing an example (1) of a control signal processing circuit.

FIG. 7 is a diagram illustrating an example (2) of a control signal processing circuit.

FIG. 8 is a diagram illustrating a method of realizing a non-block multi-input multi-stage spatial optical switch.

9 is a diagram showing an equivalent circuit of the 8 × 8 non-block multistage spatial optical switch shown in FIG.

FIG. 10 is a diagram showing a configuration example of a control signal.

FIG. 11 is a diagram showing an embodiment of the present invention.

FIG. 12 is a diagram illustrating an input light D (1, i) in the embodiment of FIG.
It is a figure which shows the example of the control information which it has.

13 is a diagram showing an equivalent circuit of the optical path switching control in the embodiment of FIG.

FIG. 14 is a diagram collectively showing a node through which incident light passes in each stage and parameters in each node.

15 is a diagram showing optical paths on an optical switch for all input light in the embodiment of FIG.

16 is a diagram showing equivalent wiring for the example of FIG.

[Explanation of symbols]

1 Polarization Separator 2 ₁ , 2 ₂ Polarization Controller 3,6 λ / 4 Plate 4 Optical Path Changer 7 Reflector 9, 10 Photo Detector

Claims (10)

[Claims] 1. A polarization separator (1) which allows one polarization component of incident light to pass therethrough and reflects the other polarization component orthogonal thereto to output, and an incident light side of the polarization separator (1). A polarization controller (2 ₁ ) that is arranged and outputs the input light (IN) by changing the polarization direction of the input light (IN) as it is or by changing it in a direction orthogonal to this.
And a λ / 4 plate (3) arranged perpendicularly to the reflected light of the polarization separator (1) so that the principal axis forms 45 ° with the polarization direction of the incident light.
And an optical path changing element (4) that reflects the incident light from the λ / 4 plate (3) to the opposite side with respect to the central axis by shifting the optical path by an amount peculiar to the element. The block (5) and a λ / 4 plate (6) arranged perpendicular to the light passing through the polarization splitter (1) so that the optical axis forms 45 ° with the polarization direction of the incident light.
And a second reflection block (8) including a reflection mirror (7) for reflecting the incident light from the λ / 4 plate (6) in the same optical path, and in the polarization controller (2 ₁ ). By controlling the polarization direction, the optical path of the vertically-polarized or horizontally-polarized input light (IN) is changed as it is or in the direction perpendicular to the traveling direction according to the separation direction of the polarization separator (1) to output light (OUT). Generating a spatial light switch, or a spatial light switch in which the first reflection block (5) and the second reflection block (8) are interchanged, or the polarization controller (2 ₁ ) and an optical path changing element. In a spatial optical switch in which (4) is arranged in an array to enable a plurality of optical inputs, in the input light (IN), an information signal light and a control signal light of a polarization controller having the same polarization as the information signal light are superposed. ,
A part of the control signal light is transmitted through the optical path changing element (4) and the reflecting mirror (7), and the transmitted control signal light is placed behind the optical path changing element (4) and the reflecting mirror (7). By detecting with the photodetectors (9) and (10) arranged, the control signal can be obtained regardless of the polarization direction of the input light (IN) or even when lights of different polarization directions are simultaneously input. A method of controlling a polarization control type spatial optical switch, which is capable of being detected and given to the polarization controller (2 ₂ ) of the next stage as control information. 2. In the input light, a control signal is superimposed on an information signal in a time division manner, and at the same time, a part of the light is transmitted through the optical path changing element (4) or the reflecting mirror (7) and the remaining light is transmitted. In the photodetector (9) or (10), the input light has a property of reflecting light, and a part of the input light passes through the optical path changing element (4) or the reflecting mirror (7). The control method of the polarization control type spatial optical switch according to claim 1, wherein the control information is detected. 3. The reflection part of the optical path changing element (4) or the reflection mirror (7) has the effect of a wavelength filter, and the information signal light of the wavelength reflected by the reflection part and a part thereof are From the input light (IN) wavelength-multiplexed with the control signal light having the wavelength that passes through the reflecting portion, the photodetectors (9), (1
The control method according to claim 1, wherein the control information is detected by 0). 4. The phase difference between the ordinary light and the extraordinary light generated by the λ / 4 plates (3) and (6) in terms of the wavelength of the information signal light and the wavelength of the control signal light is (2mπ + π / 2). ) Radians (m is an integer) so that a difference in characteristics of the λ / 4 plate due to a difference in wavelength between the information signal light and the control signal light does not occur. Three
A method of controlling the polarization control type spatial light switch described in [4]. 5. The spatial light switch according to claim 1.
Switch is connected in multiple stages from 0 to (2^N−
2 sequentially numbered by the integer of 1)^NInput
And output and 2^N-1, ..., 2^Nn, ..., 2⁰Chan
N-stage 2 of Nell shift (n = 1, 2, ..., N)^Nnode
Optical switch stage for general routing
Switch network, or one-stage or multiple-stage detours
An optical switch network configured by adding optical switch stages, or
In these cases, the optical switch with the order of the optical switch stages changed.
In the general routing stage of the H-network, the address of the output node to be reached is represented by an N-bit
Bit binary serial signal starts with “1” synchronization at any time
Bit B for another_disAs an N + 1 bit signal with
Control signal S given by_cntAnd the control signal S at each stage_cntExtracted from the control signal S_cntof
The pulse width is about the same as the width of one pulse, and 2^Nnshift
In the stage, the synchronization signal S synchronized with the nth bit_synAnd 2^NnN in binary notation of the node number at the shift stage
Number of stages and node status represented by the bit number
Signal S_nodeAnd an optical path changing element (4) in a certain optical switch stage
If the laterally polarized light of the separator (1) is on the output side, "0" is set.
And becomes "1" when the vertically polarized light is on the output side.
A signal S representing the position of the path changing element (4)_opsIf you set and, and give priority to the incident light of the horizontal polarization,
(Horizontal polarization control signal S _cntAnd signal S_nodeAnd signal S_opsof
Negative exclusive OR and horizontal polarization sync signal S_synProduct of
And (vertical polarization control signal S_cntAnd signal S_nodeDenial and signal
S_opsExclusive-OR of Negative and horizontal polarization sync signal S_syn
When the result is “0”
Outputs the polarization of the incident light as it is, and the result is "1".
The next step is to rotate the polarization of the incident light by 90 °.
Controls the state of the polarization controller for the same numbered node in the controller array.
However, when giving priority to the incident light of the vertical polarization,
(Horizontal polarization control signal S _cntAnd signal S_nodeAnd signal S_opsof
Negative exclusive OR and vertically polarized sync signal S_synWith the denial of
Product of) and (vertical polarization control signal S_cntAnd signal S_nodeDenial of
And signal S_opsExclusive-OR of Negative and Vertically Polarized Sync Signals
S_synWhen the result is “0”
Outputs the polarization of the incident light as it is, and the result is “1”.
The next step is to rotate the polarization of the incident light by 90 °.
Controls the state of the polarization controller for the same numbered node in the controller array.
Control or control signal S_cnt,Signal S_node,Sync signal S_sys,signal
S_opsThe same as the above control for control information consisting of
Polarization control characterized by performing logical processing that produces an effect
Control method for a compact space optical switch. 6. The method of controlling a polarization control type spatial optical switch according to claim 5, wherein the value of the signal S _node is fixed at each stage and each node, and vertically polarized light is emitted from the polarization separator (1). In the configuration in which the optical path changing element (4) is arranged in the direction of the horizontal direction, when the incident light of the laterally polarized light in that stage is prioritized, the signal S _node is “0” (the laterally polarized control signal S _cnt and horizontal polarization of the synchronizing signal S _syn and product) (vertical polarization of the control signal S sync signal S negative and horizontal polarization of _cnt
taking the sum of the product) of the negative of _syn, the result is as it is the polarization of the incident light when it is "0", "1" the polarization of the incident light when to rotate 90 °, the signal S _node Is "1", (control signal S
takes the sum of _cnt negative and horizontally polarized light synchronizing signal S _syn and product) and with (the product of the negation of the synchronizing signal S _syn vertical polarization of the control signal S _cnt and horizontal polarization), the result is "0" When, the polarization of the incident light is unchanged, and when it is “1”, the polarization of the incident light is 90%.
The state of the polarization controller of the node of the same number in the polarization controller array of the next stage is controlled so as to rotate by °, or the optical path changing element (4) is output in the direction in which the vertically polarized light is emitted from the polarization separator (1). ) Is arranged,
When giving priority to the vertically polarized incident light in that stage,
At the point where the signal S _node is “0”, (horizontal polarization control signal S
The product of _cnt and the negation of the vertically polarized sync signal S _syn ) and (the product of the negation of the vertically polarized control signal S _cnt and the vertically polarized sync signal S _syn ) are summed, and the result is “0”. When, the polarization of the incident light is unchanged, and when it is “1”, the polarization of the incident light is 90%.
In order to rotate the signal S _node at “1”, (the control signal S
The product of the negation of _{cnt and} the negation of the vertically polarized sync signal S _syn ) and the product of the vertically polarized control signal S _cnt and the vertically polarized sync signal S _syn is taken, and the result is “0”. When, the polarization of the incident light is unchanged, and when it is “1”, the polarization of the incident light is 90%.
The state of the polarization controller of the node of the same number in the polarization controller array of the next stage is controlled so as to be rotated by °, or the optical path changing element (4) is output in the direction in which the laterally polarized light is emitted from the polarization separator (1). ) Is arranged,
When giving priority to the horizontally polarized incident light in that stage,
At the point where the signal S _node is “1”, (control signal S
The product of _cnt and the horizontally polarized sync signal S _syn ) is multiplied by (the product of the negation of the vertically polarized control signal S _{cnt and} the negation of the horizontally polarized sync signal S _syn ), and the result is “0”. When, the polarization of the incident light is unchanged, and when it is “1”, the polarization of the incident light is 90%.
In order to rotate the signal S _node at “0”, the (polarization control signal S
The product of the negation of _cnt and the synchronizing signal S _syn of the vertically polarized light) and the product of the control signal S _cnt of the vertically polarized light and the negation of the synchronizing signal S _syn of the horizontally polarized light is taken, and the result is "0". When it is, the polarization of the incident light is unchanged, and when it is “1”, the polarization of the incident light is 90%.
The state of the polarization controller of the node of the same number in the polarization controller array of the next stage is controlled so as to be rotated by °, or the optical path changing element (4) is output in the direction in which the laterally polarized light is emitted from the polarization separator (1). ) Is arranged,
When giving priority to the vertically polarized incident light in that stage,
When the signal S _node is “1”, (control signal S
The product of _cnt and the negation of the vertically polarized sync signal S _syn ) and (the product of the negation of the vertically polarized control signal S _cnt and the vertically polarized sync signal S _syn ) are summed, and the result is “0”. When it is, the polarization of the incident light is unchanged, and when it is “1”, the polarization of the incident light is 90%.
_So that the signal S _node is “0”, the (horizontal polarization control signal S
The product of the negation of _{cnt and} the negation of the vertical polarization synchronization signal S _syn ) and the product of the vertical polarization control signal S _cnt and the vertical polarization synchronization signal S _syn, and the result is “0”. When it is, the polarization of the incident light is unchanged, and when it is “1”, the polarization of the incident light is 90%.
A method of controlling a polarization control type spatial optical switch, characterized in that the state of the polarization controller of the node of the same number in the polarization controller array of the next stage is controlled so as to rotate. 7. The polarization control type spatial light according to claim 5 or 6, wherein the value of the signal S _node in the detour optical switch stage is controlled uniquely. How to control the switch. 8. The method of controlling a polarization control type spatial light switch according to claim 5, 6 or 7, wherein a control signal S
_cnt is a specific bit B _dis and a sequence of bits necessary for control at each stage are repeated several times, and a synchronization signal S _syn generated from the control signal S _cnt is synchronized with the bit. By setting the repetition interval to be equal to or longer than the time τ which is the operation speed of the processing circuit of the control signal and the operation speed of the polarization controller, the control signal detected in the next stage can be transmitted to the optical path. A polarization control type spatial optical switch control method, characterized in that light is prevented from entering the next stage before being switched. 9. The method of controlling a polarization control type spatial light switch according to claim 5, 6 or 7, wherein a control signal S
_By transmitting _cnt , the information signal light after repeating the number of optical switch stages several times or more at a time interval of τ or more, which is the combined operation speed of the control signal processing circuit and the operation speed of the polarization controller. A method for controlling a polarization control type spatial optical switch, characterized in that the influence of the operating speed of a control signal processing circuit and the operating speed of a polarization controller is removed. 10. The method for controlling a polarization control type spatial optical switch according to claim 5, 6 or 7, wherein an optical buffer is inserted immediately before the polarization controller at each stage, and the operation speed of a control signal processing circuit is increased. Time τ including the operation speed of the polarization controller
A method for controlling a polarization control type spatial optical switch, characterized in that the effects of the operation speed of a control signal processing circuit and the operation speed of a polarization controller are removed by performing the above-mentioned time buffering.