JPH04128713A - Light signal variable delay device - Google Patents

Abstract

PURPOSE:To eliminate the need to convert a light signal into an electric signal by outputting the light signal with delay of a desired delay time based upon the time, required for the reciprocal travel of the light signal between a 1st and a 2nd reflecting mirror, as a unit. CONSTITUTION:When a 3rd polarization control part 10 is in a 1st state, horizontal polarized light which is inputted to a 9th port 10a is outputted from a 10th port 10b while held in the polarized state, reflected by a 2nd reflecting mirror 12 to pass through the 3rd polarization control part 10 again, and inputted as the horizontal polarized light to a polarized light separation part 4. Then the light signal is horizontally polarized as long as the 2nd polarization control part 6 and 3rd polarization control part 10 are in the 1st state, so this light signal is delayed corresponding to the optical path difference by traveling reciprocally between the 1st reflecting mirror 8 and 2nd reflecting mirror 12. After the light signal travels reciprocally between the reflecting mirrors a specific number of times, the 3rd polarization control part 10 is switched from the 1st state to a 2nd state and the light signal which is propagated as the horizontal polarized light is converted into vertical polarized light. Thus, the need to convert the light signal into the electric signal is eliminated.

Description

[Detailed Description of the Invention] Table of Contents Overview Industrial Field of Application Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems Implementation Examples Summary of Effects of the Invention Concerning an optical signal variable delay device. The purpose of the present invention is to provide the above-mentioned device having a variable delay time that does not require converting a signal into an electrical signal, and has, for example, a first port and a second port, and converts an optical signal input into the first port into a control signal. a first polarization control unit that outputs either vertically polarized light or horizontally polarized light whose polarization planes are orthogonal to each other based on the second port, and third to sixth ports, the third port being The vertically polarized light and the horizontally polarized light input to the third port are output from the fourth port and the sixth port, respectively, and the fifth port
a polarization separation unit that outputs the vertically polarized light input to the port from the sixth port and outputs the horizontally polarized light input to one of the fourth port and the fifth port from the other; and the seventh port and the eighth port. a first state in which the seventh port is connected to the fourth port, and outputs the light input to either one of the seventh port and the eighth port from the other without rotating the plane of polarization; a second polarization control section that switches based on a control signal between a second state in which the light input to either one of the seventh port and the eighth port is rotated by 90 degrees and output from the other; and the eighth port. a first reflecting mirror that reflects light emitted from the mirror and inputs it to the eighth port; a ninth port and a tenth port; the ninth port is connected to the fifth port; Port and 10th
A first state in which light input to one of the ports is output from the other without rotating the plane of polarization, and a state in which light input to either one of the 9th port and the 10th port is output from the other port without rotating the plane of polarization.
a third polarization control unit that switches between a second state in which the light is rotated and outputted from the other side based on a control signal; and a second reflection unit that reflects the light output from the tenth port and inputs the reflected light to the tenth port. and the first polarization control such that vertically polarized light is output from the second port when delaying the optical signal and horizontally polarized light is output from the second port when not delaying the optical signal. When the optical signal passes through the second polarization control section for the first or second time, the second polarization control section enters the second state, and at other times, the second polarization control section enters the second state. A control signal is sent to the second polarization control section so that the polarization control section enters the first state, and when the optical signal passes through the third polarization control section a number of times corresponding to the required delay time, and a control circuit that sends a control signal to the third polarization control section so that the third polarization control section is in the second state and the third polarization control section is in the first state at other times. .

Industrial applications The present invention relates to an optical signal variable delay device.

With the development of optical communication networks, optical signal processing is required to process signals as they are without intervening optical/electrical conversion or electrical/optical conversion between optical transmission lines and optical terminals such as subscribers. The introduction of technology is considered as one measure to cope with the increase in the amount of signal processing, and various methods are being considered. In this process, information for the same destination, such as ATM transmission/switching and packet switching, is transmitted as an information string called a continuous cell or packet, and the information string is divided based on the destination information given at the beginning of this information string. Studies are being conducted in various fields to introduce optical signal processing technology into information transmission systems that identify destinations. In this type of transmission system, if signal sequences addressed to the same receiving station or the same route assignment node are simultaneously sent from different transmitting stations, information collisions will occur at the receiving station or node, resulting in incorrect reception or replay. It may not be sent. Therefore, when the presence of signals addressed to the same receiving station or the same route allocation node is detected, only one of the signals is received, and the other signals are detoured, waited, or It is desirable that the signals be selected to be received in order after undergoing processing such as storage. It is required to provide a buffer that holds data for a certain period of time or a processing circuit that performs delay processing (hereinafter collectively referred to as a "buffer memory").

2. Description of the Related Art In the ATM, packet transmission and exchange systems that have been studied in the past, the information buffer memory is entirely based on electrical signal processing. Specifically, all transmitted optical signals are converted into electrical signals, and an electrical signal processing circuit reads information called a header at the beginning of a cell or packet, allocates a route depending on the destination, and prevents information collisions. If there is a risk of this occurring, only one of the pieces of information is selectively transmitted, the other information is stored in an electrical buffer memory, and the stored information is transferred once the route can be secured. is read out and transmitted.

Problems to be Solved by the Invention Therefore, in order to handle ultra-high-speed optical signals in optical trunk systems, for example, in the electrical signal processing proposed in the past, ultra-high-speed optical/electrical conversion units and electrical signal processing are required. department and electricity/
This requires an optical conversion section, which could become a bottleneck in terms of processing speed as the capacity of the signals handled increases. Also, A
150 to 600, which is considered the basic unit in TM transmission, etc.
Although it is possible to process signals with a speed of about Mb/s using electrical circuits, there is a problem that the processing equipment may become larger in size as the number of channels to be connected increases to several thousand or more. There was also.

The present invention was created in view of the above-mentioned problems caused by converting an optical signal into an electrical signal. The purpose is to provide equipment.

Means for Solving the Problems The above-mentioned technical problems are solved by any one of the first to third configurations of the present invention.

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

This optical signal variable delay device has a first port 2a and a second port 2b, and converts the optical signal input to the first port 2a into either vertically polarized light or horizontally polarized light whose polarization planes are orthogonal to each other based on a control signal. a first polarization control unit 2 that outputs from a second port 2b; a third to sixth ports 4a;
4b4c, 4d, and the third port 4a is the second port 2.
b, and the vertically polarized light and horizontally polarized light input to the third port 4a are transmitted to the fourth port 4b and the sixth port 4d, respectively.
The vertically polarized light outputted from the fifth port 4c and inputted to the fifth port 4c is
a polarization separation unit 4 that outputs horizontally polarized light from the port 4d and inputted to one of the fourth port 4b and the fifth port 4c, and outputs the horizontally polarized light from the other; a seventh port 6a and an eighth port 6;
b, the seventh port 5a is connected to the fourth port 4b, and a first state in which the light input to either the seventh port 5a or the eighth port 6b is output from the other without rotating the plane of polarization. and a second state in which the polarization plane of the light input to either one of the seventh port 5a and the eighth port 6b is rotated by 90 degrees and output from the other, based on a control signal. 6, a first reflecting mirror 8 that reflects the light output from the eighth port 6b and inputs it to the eighth port 6b, a ninth port 10a and a tenth port 10b, and the ninth port 10a is connected to the fifth port 6b. Connected to port 4c,
A first state in which the light input to either one of the port 10a or the tenth port 10b is output from the other without rotating the plane of polarization, and a first state in which the light input to either the ninth port 10a or the tenth port 10b is polarized. A third polarization control unit 10 switches between a second state in which the surface is rotated by 90° and output from the other side based on a control signal, and the light output from the tenth port ib is reflected and input to the tenth port lQb. a second reflecting mirror 12; and a second reflecting mirror 12 when delaying the optical signal.
When vertically polarized light is output from the port 2b and no delay is given to the optical signal, a control signal is sent to the first polarization controller 2 so that horizontally polarized light is output from the second port 2b, and the optical signal is output from the second port 2b.
The second polarization control unit 6 is in the second state when passing through the polarization control unit 6 for the first or second time, and the second polarization control unit B6 is in the first state at other times. When the optical signal passes through the third polarization control section 10 a number of times corresponding to the required delay time, the third polarization control section 10 enters the second state. The third polarization controller 10 is set to the first state when the third polarization controller 10 is in the first state.
and a control circuit 14 that sends a control signal to the polarization control B10.

FIG. 2 is a block diagram showing a second configuration of the present invention.

This optical signal variable delay device has a first port 22a and a second port 22a.
a first port 22b, which converts the optical signal input into the first port 22a into horizontally polarized light and outputs it from the second port 22b;
polarization control unit 22 and third to fifth ports 24a, 24
b, 24c, and the third port 24a is the second port 22
b, outputs the horizontally polarized light input to the third port 24a from the fifth port 24c, and outputs the vertically polarized light input to either one of the fourth port 24b and the fifth port 24c from the other. Separation part 24 and fourth port 2
A first reflecting mirror 26 that reflects the light output from 4b and inputs it to the fourth port 24b, and a sixth port 28a and a seventh port 24b.
It has a port 28b, and the sixth port 28a is the fifth port 2.
4c, the sixth port 28a and the seventh port 28
a first state in which the light input to either one of the ports 28a and 28b is output from the other without rotating the plane of polarization, and the sixth port 28a and the seventh port
The polarization plane of the light input to either port 28b is 9.
It has a second polarization control unit 28 that switches between a second state in which the light is rotated by 0° and output from the other side based on a control signal, and eighth to tenth ports 30a, 30b, and 30C, and the eighth port 30a is the second state in which the second state is output from the other side. A second port is connected to the seventh port 28b, outputs the horizontally polarized light input to the eighth port 30a from the tenth port 30c, and outputs the vertically polarized light input to either one of the eighth port 30a and the ninth port 30b from the other. a polarization separation unit 30, and a second reflecting mirror 32 that reflects the light output from the ninth port 30b and inputs it to the ninth port 30b.
When the optical signal is not delayed, the second polarization controller 28 maintains the first state.
When sending a control signal to 8 and giving a delay to the optical signal,
The second polarization control section 28 when the optical signal passes through the second polarization control section 28 for the first time and when the optical signal passes through the second polarization control section 28 an odd number of times depending on the required delay time.
is in the second state, and a control circuit 34 sends a control signal to the second polarization control unit 28 so that the second polarization control unit 28 is in the first state at other times.

FIG. 3 is a block diagram showing a third configuration of the present invention.

This optical signal variable delay device has a first port 42a and a second port 42a.
A first polarization control unit 42 which has a port 42b and converts the optical signal input to the 1R1 port 42a into horizontally polarized light and outputs it from the second port 42b, and third to sixth ports 44a, 4
4b, 44c, and 44d, and the third port 44a is the second
It is connected to the port 42b, outputs the horizontally polarized light input to the third port 44a from the fifth port 44c, and
a first polarization separation unit 44 that outputs the vertically polarized light input to 4c from the sixth port 44d, and outputs the horizontally polarized light input to either the fourth port 44b or the sixth port 44d from the other; a first reflecting mirror 46 that reflects the light output from 44b and inputs it to the fourth port 44b;
A first polarization conversion 84 that rotates the polarization plane of the light output from the fifth port 44c by 90 degrees and inputs the light to the fifth port 44c.
8, a seventh port 50a and a second port 50b,
The seventh port 50a is connected to the sixth port 44d, and the seventh port 50a is connected to the sixth port 44d.
A first port that outputs light input to either one of the port 50a and the eighth port 50b from the other without rotating the plane of polarization.
A second polarization control unit 50 that switches between the state and a second state in which the polarization plane of the light input to either one of the seventh port 50a and the eighth port 5Qb is rotated by 90 degrees and output from the other, based on a control signal. and the ninth to twelfth ports 52a
, 52b, 52c, and 52d, the ninth port 52a is connected to the eighth port 50b, and the vertically polarized light input to the ninth port 52a is output from the tenth port 52b.
The horizontally polarized light input to the port 52b is transferred to the 12th port 52d.
output from the ninth port 52a and the eleventh port 52C.
a second polarization separation section 52 that outputs the horizontally polarized light input to one of the two ports from the other;
and a second polarization conversion unit 56 that rotates the polarization plane of the light output from the tenth port 52b by 90 degrees and inputs the light to the tenth port 52b, and when no delay is given to the optical signal, When the second polarization control section 50 sends a control signal to the second polarization control section 50 to maintain the first state and gives a delay to the optical signal, the optical signal is transmitted to the second polarization control section 50.
The second polarization control section 50 is in the second state when the optical signal passes through the second polarization control section 50 for the first time and when the optical signal passes through the second polarization control section 50 an odd number of times according to the required delay time, and at other times. and a control circuit 58 that sends a control signal to the second polarization control section 50 so that the second polarization control section 50 is in the first state.

In a preferred embodiment of the third configuration, the first polarization conversion section 48 and the second polarization conversion section 56 are each 1/4
A wavelength plate 60 and a reflecting mirror 62 are provided.

In another preferred embodiment of the third configuration, the first polarization converter 48 and the second polarization converter 56 each include a 45° Faraday rotator instead of the quarter-wave plate 60 in the above-described preferred embodiment. It is equipped with

In the specification of this application, the terms "horizontal polarized light" and "vertical polarized light" are used relatively to mean that the polarized light they represent is linearly polarized light, and the planes of polarization are orthogonal to each other. This does not mean that these planes of polarization have a limited positional relationship with respect to the arrangement of the components of the device.

For example, when a polarization beam splitter equipped with a polarization separation film is used as a polarization separation unit, vertically polarized light is polarized light whose plane of polarization is perpendicular to the plane of incidence on the polarization separation film (S-polarized light). It is only necessary to consider that horizontally polarized light is polarized light (P-polarized light) whose plane of polarization is parallel to the plane of incidence on the polarization separation film.

Operation The operation of the first configuration of the present invention will be explained with reference to FIG. When there is no need to give a delay to the optical signal, the first polarization control unit 2 is controlled so that horizontally polarized light is output from the second port 2b, so this horizontally polarized light is output from the third port 4a and the sixth port. 4d from this device without any delay. On the other hand, when trying to give a delay to the optical signal, the first polarization control 8B2 is controlled so that vertically polarized light is output from the second port 2b. The signal is inputted to the seventh port 5a through the four ports 4b in this order. The second polarization control unit 6 is controlled so that the optical signal enters the second state when it passes through the second polarization control unit 6 for the first or second time. side! After passing through the 0 section 6, being reflected by the first reflecting mirror 8, and passing through the second polarization control section 6 again, it becomes horizontally polarized light. The horizontally polarized light output from the seventh port t-6a is input to the ninth port 10a via the fourth port 4b and the fifth port 4c in this order. Now, assuming that the third polarization control section 10 is in the first state, the ninth port 1
The horizontally polarized light input to 0a is transferred to the first
The light is output from the 0 port 10b, is reflected by the second reflecting mirror 12, passes through the third polarization control section 10 again, and is input to the polarization separation section 4 as horizontally polarized light. After this, as long as the second polarization control section 6 and the third polarization control section 10 are in the first state,
Since the optical signal is horizontally polarized, this optical signal
The light travels back and forth between the second reflecting mirror 8 and the second reflecting mirror 12, and is given a delay corresponding to the optical path difference. When the optical signal makes the required number of trips between the reflecting mirrors, the third polarization control unit 10 is switched from the first state to the second state, and the optical signal propagating as horizontally polarized light is converted to vertically polarized light. When the optical signal converted into vertically polarized light is input to the fifth port 4c, this light is not output from the fourth port 4b but is sent to the sixth port 4.
It is output from d. Thus, according to the first configuration,
It becomes possible to give a desired delay time to an optical signal and output it in units of time during which the optical signal travels back and forth between the first reflecting mirror 8 and the second reflecting mirror 12.

The operation of the second configuration of the present invention will be explained with reference to FIG. The optical signal input to the first port 22a is output as horizontally polarized light from the second port 22b, and this horizontally polarized light is input to the sixth port 28a via the third port 24a and the fifth port 24c in this order. When no delay is given to the optical signal, the second polarization controller 28 is maintained in the first state, so the horizontally polarized light input to the sixth port 28a is sent to the seventh port 28b without having its polarization state converted. The signal is outputted from this device through the eighth port 30a and the tenth port 30c in this order without any delay. on the other hand,
When delaying the optical signal, when the optical signal passes through the second polarization control section 28 for the first time, the second polarization control section 2
8 is controlled to be in the second state, the optical signal that passes through the first polarization control section 22 and the first polarization separation section 24 in this order and is input to the second polarization control section 28 as horizontally polarized light is , is output from the seventh port 28b as vertically polarized light.

The vertically polarized light output from the 7th port 28b passes through the 8th port 30a and the 9th port 30b in this order, is reflected by the second reflecting mirror 32, and is reflected by the 9th port 30b and the 8th port 30b.
0a in this order and input to the seventh port 28b. At this time, the second polarization control section 28 is in the first state, so the optical signal is output from the sixth port 28a as vertically polarized light, and passes through the fifth port 24c and the fourth port 24b in this order to the first state. It is reflected by the reflecting mirror 26, passes through the fourth port 24b and the fifth port 24c in this order, and enters the sixth port 28a. Therefore, as long as the second polarization control unit 28 is in the first state, the optical signal propagating as vertically polarized light travels back and forth between the first reflecting mirror 26 and the second reflecting mirror 32 and is delayed. It will be. When the optical signal passes through the second polarization control unit 28 an odd number of times after the optical signal has made a required number of reciprocations between the first reflecting mirror 26 and the second reflecting mirror 32, that is, the light propagates as vertically polarized light. When the signal passes through the second polarization control section 28 from left to right in FIG. 2, the second polarization control section 28 is switched from the first state to the second state. Then, since the vertically polarized light input to the sixth port 28a is output as horizontally polarized light from the seventh port 23b, this horizontally polarized light is output from this device via the eighth port 30a and the tenth port 30C in this order. Become. in this way,
A desired delay time can be given to the optical signal based on the unit of time the optical signal travels back and forth between the first reflecting mirror 26 and the second reflecting mirror 32. The reason why the second polarization control section 28 is controlled to be in the second state when the optical signal passes through the second polarization control section 28 on an odd-numbered time is because the second polarization control section 28 is controlled to enter the second state when the optical signal passes through the second polarization control section 28 on an even-numbered time. When the polarization control unit 28 of No. 2 is set to the second state, the optical signal (vertically polarized light) input to the seventh port 28b is output from the sixth port 1-2.8a as horizontally polarized light, and this vertically polarized light is This is because the optical signal is output from the input side via the fifth port 24c and the third port 24a in this order, and the optical signal cannot be extracted from the tenth port 30C.

The operation of the third configuration of the present invention will be explained with reference to FIG. The optical signal input to the first port 42a is output as horizontally polarized light from the second port 42b, and
The light is then input to the first polarization converter 48 via the fifth port 44c. The horizontally polarized light input to the first polarization converter 48 is
The plane of polarization is rotated by 90 degrees in the first polarization converter 48, that is, it becomes vertically polarized light, and is inputted to the fifth port 44c, and then inputted to the seventh port 50a via the sixth port 44d.

When no delay is given to the optical signal, the second polarization control unit 5
0 is maintained in the first state, the seventh port 50a
The vertically polarized light input to the is output as is from the eighth port 50b, passes through the ninth port 52a and the tenth port 52b, and is input to the second polarization converter 56, where it is converted into horizontally polarized light and sent to the tenth port 52b. Enter again. The horizontally polarized light input to the 10th port 52b is outputted from this device through the 12th port 52d without being delayed.

On the other hand, when delaying the optical signal, the optical signal passes through the second polarization control section 50 for the first time i! 1. Since the second polarization control unit 50 is controlled to enter the second state at the appropriate time, the vertically polarized light input to the seventh port 50a is output as horizontally polarized light from the eighth port 50b. 8th port 50b
The optical signal output as horizontally polarized light from the 9th port 52
a and the eleventh port 52c in this order, is reflected by the reflecting mirror 54, passes through the eleventh port 52C and the ninth port 52a in this order, and enters the eighth port 50b. At this time,
Since the second polarization control unit 50 is in the first state, horizontally polarized light is output from the seventh port 50a, and this horizontally polarized light passes through the sixth port 44d and the fourth port 44b in this order and then reaches the first reflecting mirror 46. reflected at the fourth port 44b and the sixth port 44b.
The signal passes through the port 44d in this order and is input again to the seventh baud 1-50a. Therefore, as long as the second polarization control unit 50 is in the first state, the optical signal propagating as horizontally polarized light travels back and forth between the first reflecting mirror 46 and the second reflecting mirror 54 and is delayed. It will be. After the optical signal has gone back and forth between the first reflecting mirror 46 and the second reflecting mirror 54 a required number of times, when it passes through the second polarization control section 50 an odd-numbered time, the second polarization control section 50 When the first state is switched to the second state, the horizontally polarized light input to the seventh port 50a is output as vertically polarized light from the eighth port 50b, and this vertically polarized light is transmitted to the ninth port 52a and the tenth port 52b. The light is inputted to the second polarization converter 56 in this order. Second polarization converter 5
The light input to port 6 has its polarization plane rotated by 90 degrees and outputs from the second polarization converter 56, so it is outputted from the 10th port 5 again.
The light input to 2b is horizontally polarized. Therefore, this horizontally polarized light is output from this device via the twelfth port 52d.

In this way, also with the third configuration, the first reflecting mirror 46
A desired delay time can be given to the optical signal in terms of the time it takes for the optical signal to travel back and forth between the mirror and the second reflecting mirror 54. Note that in the third configuration, the reason why the second polarization control unit 50 is controlled to be in the second state when the optical signal passes through the second polarization control unit 50 an odd number of times is because the second polarization control unit 50 The reason is the same as in the configuration of .

As described above, according to any one of the first to third configurations of the present invention, it is possible to provide a variable optical signal delay device whose delay time is variable and does not require converting an optical signal into an electrical signal.

Example The present invention will be explained in detail below.

FIG. 7 is a block diagram of an optical buffer memory section showing an embodiment of a second configuration of the present invention. This optical buffer memory section is used, for example, when the communication path in an ATM switch is opticalized. In the optical buffer memory 62, 64 is an optical coupler that branches the input optical signal into two paths at a predetermined ratio. One of the optical signals branched by the optical coupler 64 is optical/
It is input to the electrical conversion circuit 66. The optical/electrical conversion circuit 66 converts an optical signal into an electrical signal in order to process the first header 70a of the input optical signal 70. light/
The header processing circuit 68 to which the signal from the electrical conversion circuit 66 is input reads the header signal sent from the optical/electrical conversion circuit 66, and performs route setting, header attachment, buffer memory button control, etc. . The header switching circuit 72 to which the other optical signal branched by the optical coupler 64 is input converts the header of the input optical signal as necessary under the control of the header processing circuit 68. Replacement circuit 7 with header
The optical output of No. 2 is input to the first polarization control section 22 of the optical signal variable delay device. As the first polarization control section 22 and the second polarization control section 28, for example, an E10 polarization converter that utilizes the electro-optic effect of a nonlinear optical element can be used. Moreover, a polarization beam splitter can be used as the first polarization separation section 24 and the second polarization separation section 30. In this embodiment, the control circuit 34 determines control timing and the like based on a signal from the header processing circuit 68.

Regarding the case where the optical signal is delayed by one time unit time,
The operation will be described assuming that the polarization separation films of the polarization beam splitters used as the first polarization separation section 24 and the second polarization separation section 30 are arranged perpendicularly to the plane of the paper. The first polarization control section 22 is controlled so that its optical output becomes P-polarized light. This P-polarized light passes through the polarization separation film in the first polarization separation section 24 and is input to the second polarization control section 28, where it is converted into S-polarized light. This S-polarized light is reflected by the polarization separation film of the second polarization separation section 30 and also reflected by the reflecting mirror 32, and is then sent to the second reflection mirror 32, the second polarization separation 930, and the second polarization control! 11 section 28, the first polarization separation section 24, and the first reflecting mirror 26. The optical signal then controls the second polarization control section 28 by 3.
During the second pass, this optical signal is converted from S-polarized light to P-polarized light, and the 20P-polarized light is transmitted through the polarization separation film of the second polarization separation section 30 and output from the optical buffer memory 62 to the outside.

In this way, according to the present embodiment, it is determined by the arrangement of the first reflecting mirror 26, the first polarization separation B24, the second polarization control section 28, the second polarization separation section 30, and the second reflection mirror 32. An arbitrary delay time can be set using the unit delay time as a unit.

Regarding the first configuration or the second configuration of the present invention, the fourth configuration
Since it can be implemented in the same manner as the embodiment shown in the figure,
The explanation will be omitted.

In the embodiment described with reference to FIG. 4, the constituent parts are individual optical parts and the optical path is set in space, but the constituent parts may be coupled by optical fibers. Moreover, each component may be provided integrally, for example, as an optical waveguide component. When connecting each component with an optical fiber, by using a polarization-maintaining optical fiber and applying a total reflection coating to its end face, there is no need for a reflecting mirror, and the optical fiber is suitable for small size. It becomes possible to provide a signal variable delay device. Furthermore, in the embodiments described above, an E10 polarization converter that utilizes the electro-optic effect of a nonlinear optical element is used as a polarization control section, but it responds to optical signal input like a bistable semiconductor laser or a wavelength conversion semiconductor laser. The relationship between input and output polarization may be changed by transmitting input light or causing laser oscillation by using a drive current bias, using an element that oscillates in a TE mode.

Effects of the Invention As described above, the present invention has the effect that it is possible to provide an optical signal variable delay device that does not require converting an optical signal into an electrical signal and whose delay time is variable.

[Brief explanation of the drawing]

1 to 3 are block diagrams of an optical signal variable delay device showing the first to third configurations of the present invention, respectively. FIG. 4 is a block diagram of an optical buffer memory showing an embodiment of the second configuration of the present invention. It is a diagram. 2, 6. 10. 22. 28. 50...Polarization control unit, 4.24.30.44.52...Polarization separation unit, 8°12°26°32°46°...Reflector, 14°34°...Control circuit.

Claims (1)

[Claims] 1. It has a first port (2a) and a second port (2b), and the optical signal input to the first port (2a) is polarized vertically so that the planes of polarization are orthogonal to each other based on a control signal. a first polarization control unit (2) that outputs either polarized light or horizontally polarized light from the second port (2b); and third to sixth ports (4a, 4b, 4c, 4d); The third port (4a) is connected to the second port (2b), and transmits the vertically polarized light and horizontally polarized light input to the third port (4a) to the fourth port (4b) and the sixth port, respectively.
The vertically polarized light outputted from the port (4d) and inputted to the fifth port (4c) is outputted from the sixth port (4d), and the vertically polarized light is outputted from the sixth port (4d), and one of the fourth port (4b) and the fifth port (4c) is output. It has a polarization separation unit (4) that outputs the horizontally polarized light inputted to the other side, and a seventh port (6a) and an eighth port (6b), and the seventh port (6a) is connected to the fourth port (4b). a first state in which the light input to one of the seventh port (6a) and the eighth port (6b) is output from the other without rotating the plane of polarization; a second polarization control unit (6) that switches based on a control signal between a second state in which the light input to one of the eighth ports (6b) is rotated by 90 degrees and output from the other; It has a first reflecting mirror (8) that reflects the light output from the eighth port (6b) and inputs it to the eighth port (6b), a ninth port (10a), and a tenth port (10b). , the ninth port (10a) is the fifth port (4c)
a first state in which the light input to one of the ninth port (10a) and the tenth port (10b) is output from the other without rotating the plane of polarization; a third polarization control unit (10) that switches based on a control signal between a second state in which the light input to one of the tenth ports (10b) is rotated by 90 degrees and output from the other; a second reflecting mirror (12) that reflects the light output from the tenth port (10b) and inputs it to the tenth port (10b); and the second port (2b) when delaying the optical signal.
When vertically polarized light is output from the optical signal without delaying the optical signal, a control signal is sent to the first polarization control section (2) so that horizontally polarized light is output from the second port (2b), and the optical signal is output from the second port (2b). When passing through the second polarization control section (6) for the first or second time, the second polarization control section (6) enters the second state, and at other times, the second polarization control section ( 6) is the first
A control signal is sent to the second polarization control unit (6) so that the optical signal reaches the state, and when the optical signal passes through the third polarization control unit (10) a number of times corresponding to the required delay time, The third polarization control section (10) is controlled so that the third polarization control section (10) is in the second state and the third polarization control section (10) is in the first state at other times. Control circuit that sends signals (
14) An optical signal variable delay device comprising: 2. The first port has a first port (22a) and a second port (22b), and converts the optical signal input into the first port (22a) into horizontally polarized light and outputs it from the second port (22b).
It has a polarization control unit (22) and third to fifth ports (24a, 24b, 24c), and the third port (24a) is connected to the second port (22b).
The horizontally polarized light input to the third port (24a) is output from the fifth port (24c), and
a first polarization separation unit (24) that outputs the vertically polarized light input to either one of the port (24b) and the fifth port (24c) from the other; and a first polarization separation unit (24) that reflects the light output from the fourth port (24b). the first reflecting mirror (26) input to the fourth port (24b).
), a sixth port (28a) and a seventh port (28b), and the sixth port (28a) is connected to the fifth port (24c).
a first state in which the light input to either the sixth port (28a) or the seventh port (28b) is output from the other without rotating the plane of polarization;
28a) and a second state in which the light input to either one of the seventh ports (28b) is rotated by 90 degrees and output from the other, based on a control signal. and 8th to 10th ports (30a, 30b, 30c), and the 8th port (30a) is connected to the 7th port (28b).
), the horizontally polarized light input to the eighth port (30a) is output from the tenth port (30c), and is input to either the eighth port (30a) or the ninth port (30b). a second polarization splitter (30) that outputs vertically polarized light from the other side; and a second reflecting mirror (32) that reflects the light output from the ninth port (30b) and inputs it to the ninth port (30b).
), and when no delay is given to the optical signal, a control signal is sent to the second polarization control section (28) so that the second polarization control section (28) maintains the first state, and the optical signal is When delaying the signal, the optical signal passes through the second polarization control section (28) to 1.
When the optical signal passes through the second polarization control section (28) for the first time and when the optical signal passes through the second polarization control section (28) for an odd number of times according to the required delay time, the second polarization control section (28) enters the second state;
A control circuit (34) that sends a control signal to the second polarization control section (28) so that the second polarization control section (28) is in the first state at other times. Optical signal variable delay device. 3. The first port has a first port (42a) and a second port (42b), and converts the optical signal input into the first port (42a) into horizontally polarized light and outputs it from the second port (42b).
polarization control unit (42), and the third to sixth ports (44a, 44b, 44c, 44d
), and the third port (44a) has the second port (
42b) and outputs the horizontally polarized light input to the third port (44a) from the fifth port (44c),
The vertically polarized light input to the fifth port (44c) is
output from the port (44d), and output from the fourth port (44b).
) and the sixth port (44d), the first polarization separation unit (44) outputs the horizontally polarized light input to the other from the other.
and a first reflecting mirror () that reflects the light output from the fourth port (44b) and inputs it to the fourth port (44b).
46), and the polarization plane of the light output from the fifth port (44c) is 9
The first input to the fifth port (44c) after being rotated by 0°
a polarization converter (48), a seventh port (50a) and an eighth port (50b), and the seventh port (50a) is connected to the sixth port (44d).
a first state in which the light input to either the seventh port (50a) or the eighth port (50b) is output from the other without rotating the plane of polarization;
50a) and a second state in which the light input to either one of the eighth ports (50b) is rotated by 90 degrees and output from the other, based on a control signal. and the 9th to 12th ports (52a, 52b, 52c, 52
d), the ninth port (52a) is connected to the eighth port (50b), the vertically polarized light input to the ninth port (52a) is output from the tenth port (52b), and The horizontally polarized light input to the 10th port (52b) is output from the 12th port (52d), and the horizontally polarized light input to either the 9th port (52a) or the 11th port (52c) is output from the other. a second polarization separation unit (52) that reflects the light output from the eleventh port (52c) and inputs the reflected light to the eleventh port (52c);
54); a second polarization converter (56) that rotates the polarization plane of the light output from the tenth port (52b) by 90 degrees and inputs the light to the tenth port (52b); If not, a control signal is sent to the second polarization controller (50) so that the second polarization controller (50) maintains the first state, and if a delay is to be given to the optical signal, , the optical signal passes through the second polarization control unit (50) to 1
When the optical signal passes through the second polarization control section (50) for the first time and when the optical signal passes through the second polarization control section (50) for an odd number of times according to the required delay time, the second polarization control section (50) enters the second state;
A control circuit (58) that sends a control signal to the second polarization control section (50) so that the second polarization control section (50) is in the first state at other times. Optical signal variable delay device.