JPH08204213A - Optical switch - Google Patents

Abstract

PURPOSE: To realize a stabilized optical switch having high quenching ratio and low crosstalk in which the strength level of signal can be reproduced or amplified by constituting an optical switch element of a light receiving element and a light emitting element which can be driven with low voltage and multiplexing, demultiplexing or interconnecting the light selectively through an optical fiber array. CONSTITUTION: The optical switch comprises a demupltiplexer 4 for branching an input light 6, a multiplexer 5 for combining the output light 7, an optical fiber 3 for connecting the I/O light selectively, a lens array 2 for condensing the I/O light, and an optical switch element array 1 for receiving the I/O light selectively to emit a light. Since the optical switch element array 1 comprises surface emission lasers arranged two-dimensionally, surface type light receiving elements and a drive circuit for driving or amplifying them, a small-sized, highly efficient high speed optical switch can be realized. When the wavelength of the light emitting and receiving elements is determined selectively, an optical switch involving the wavelength conversion can be realized and applied to a wavelength multiplexing system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switching device used for highly parallel optical information transmission and optical information processing.

[0002]

2. Description of the Related Art As a conventional optical switching device, an optical waveguide 22 is formed on a lithium niobate (LiNbO ₃ ) substrate 21 as shown in FIG. 4, and an optical switch element 23 is formed at each intersection of the optical waveguide 22. There is a lithium niobate matrix switch (OFC / IOOC, 1987
Year, WB4). The light input from each input port on the left side in the figure is selected to which output port on the right side depending on the on / off state of each optical switch element 23.

[0003]

In the lithium niobate matrix switch used as the conventional optical switching device, the driving voltage is about 40 for the polarization independent type.
V and polarization dependent type require high voltage of about 15V. Further, the extinction ratio is limited to about 20 dB in the conventional example, and a large extinction ratio cannot be obtained. Further, there is an insertion loss of about 3 dB per switch. For example, in the case of a 4 × 4 matrix, the total insertion loss becomes 12 dB because it passes through 4 switches. Therefore, if the number of matrices is increased, the insertion loss becomes larger. It was a thing. In addition to this, there are problems such as crosstalk between signals and temporal fluctuation of the bias voltage.

It is an object of the present invention to realize an optical switching device which uses a light receiving element and a light emitting element which can be driven at a low voltage and which has a high extinction ratio, low crosstalk, high stability and is capable of reproducing a signal strength level. is there.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and the first invention is to provide a plurality of light receiving elements constituting an optical switch element array after demultiplexing input light by a demultiplexer. The optical signal is exchanged by combining the output light from the light emitting element paired with the light receiving element in the direction perpendicular to the optical fiber array on the input side.

According to a second aspect of the present invention, in the optical switching device of the first aspect, a surface emitting laser in which an optical switch element array is two-dimensionally arranged, a surface type light receiving element, and a drive circuit for driving or amplifying these are provided. By doing so, the exchange of a larger capacity signal line can be realized more efficiently, compactly, and at low cost.

According to a third aspect of the invention, in the optical exchanging device of the second aspect of the invention, the wavelength of the surface emitting laser or the surface type light receiving element is selectively determined, thereby enabling selective wavelength conversion. Is.

[0008]

In the optical switching device of the present invention, switching is performed using the light receiving element and the light emitting element that can be driven at a low voltage,
It is possible to reduce power consumption and downsize a driving circuit. In addition, since the input light and output light are completely separated, there is no influence of return light from the output side to the input side. Furthermore, because of the on / off control of the light emitting element, a high extinction ratio, high stability, and a signal strength level are provided. It is possible to realize an optical switching device capable of reproducing or amplifying.

Further, by constructing the light emitting element and the light receiving element by the surface emitting laser and the surface type light receiving element as in the second aspect of the invention, the exchange of the larger capacity signal line can be realized more efficiently, compactly and at low cost. It becomes possible to do.

Furthermore, by selectively determining the wavelengths of the surface emitting laser and the surface type light receiving element as in the third invention,
An optical switching device with wavelength conversion can be realized, and it can be applied to a wavelength multiplexing system.

[0011]

1 is a perspective view of an optical switching apparatus to which the first and second inventions are applied. The present optical switching device includes a demultiplexer 4 for splitting the input light 6, a multiplexer 5 for merging the output light 7, an optical fiber array 3 for guiding the input / output light, and a condenser for collecting the input / output light. It comprises a lens array 2 and an optical switch element array 1 for receiving and emitting input / output light. As shown in the enlarged view of the lower part of FIG. 1, the optical switch element array includes light receiving elements 8 (A) and light emitting elements 9 (B) arranged in every other row, and the optical multiplexers are arranged in rows A 1 to A 4 of the demultiplexer 4 and the multiplexer 5. B1
To B4 correspond to the optical fiber array 3
Is wired. The optical switch element array 1 constitutes a plurality of cells each including a light receiving element 8 and a light emitting element 9 as a pair, as indicated by a broken line in an enlarged view at the bottom of FIG. The path from the input light 6 to the output light 7 is selected depending on which is turned on. The light receiving element 8 and the light emitting element 9 are each connected to a drive circuit, and the drive circuit of the cell in the ON state amplifies the optical signal incident on the light receiving element 8 to drive the light emitting element 9 and emits the optical signal. Let

In the second embodiment, the light receiving element is a surface type light receiving element, and the light emitting element is a vertical cavity surface emitting laser. The light emitting element may be a surface emitting laser in which an edge emitting semiconductor laser has a built-in mirror for raising emitted light. The lens array 2 collects the light emitted from the optical fiber array 3 on the light receiving element 8 or collects the light emitted from the light emitting element 9 on the optical fiber array 3. Approach the optical switch element array 1,
It is also possible to directly input and output.

In the optical switching device of the present invention, an operating voltage of about 5 V is sufficient, and an extinction ratio of 40 dB or more can be obtained in this embodiment. Further, although there is a branch loss, since about 20 dB can be amplified by the drive circuit, the total insertion loss can be amplified to -8 dB in the case of 4 × 4.

FIG. 2 is a perspective view of an optical switching device to which the third invention is applied. In the optical switching device of the first invention, the input light 6 has a plurality of wavelengths, and the demultiplexers 4 and 10
Is split twice and guided to the optical switch element array 1. The wavelengths of the surface type light receiving element 8 and the surface type light emitting element array 9 constituting the optical switch element array 1 are selectively determined in advance as described in the enlarged view of the lower diagram of FIG. For example, the optical signal incident on the demultiplexer 10 with the wavelength λ1 is selectively received by only the cells in the leftmost column in the enlarged view of the lower diagram of FIG. 2, and further, from the multiplexer 5 depending on which of these cells is switched. The emitted wavelength can be selected from λ1 to λ4. Regarding the wavelengths of the surface type light receiving element 8 and the surface type light emitting element 9, those designed for the respective wavelengths as shown in FIG. 3 are arranged and fixed on the submount 12 by the flip chip bumps 11. Each wavelength is centered at about 980 nm and the wavelength interval is about 5 nm. The emission wavelength is changed by designing the resonance wavelength of the surface emitting laser, and the reception wavelength is also changed by designing the resonance wavelength using a resonator type light receiving element. As for the light receiving wavelength, a normal light receiving element may be used and a filter for wavelength selection may be inserted immediately before the light receiving wavelength, or the fiber array from the demultiplexer 4 may be changed in the direction perpendicular to FIG. A wavelength selection filter may be inserted between the four.

[0015]

As described above, by applying the present invention, it is possible to realize an optical switching device which is small in size, has a high extinction ratio, low crosstalk, high stability, and can reproduce or amplify a signal strength level.

[Brief description of drawings]

FIG. 1 is a perspective view of an optical exchanging device for explaining an embodiment of first and second inventions.

FIG. 2 is a perspective view of an optical exchanging device for explaining an embodiment of a third invention.

FIG. 3 is a sectional view of an optical switch element array for explaining an example of a third invention.

FIG. 4 is a perspective view of a lithium niobate matrix switch for explaining a conventional example.

[Explanation of symbols]

 1 optical switch element array 2 lens array 3 optical fiber array 4 demultiplexer 5 multiplexer 6 input light 7 output light 8 light receiving element 9 light emitting element 10 demultiplexer 11 flip chip bump 12 submount 21 lithium niobate substrate 22 optical Waveguide 23 Optical switch element

Claims (3)

[Claims] 1. An optical switching device for selectively exchanging a plurality of optical signals input in parallel to output an optical signal, and demultiplexing means for demultiplexing optical signals input in parallel, and inputting them in parallel. Means for multiplexing the signals to be multiplexed, an optical switch element array having light-receiving and light-emitting functions, and one end of an optical fiber connected to the demultiplexing means and the multiplexer means each element of the optical switch element array. And an optical fiber array selectively and uniquely connected to the block. 2. The optical switching element array comprises a surface emitting laser arranged two-dimensionally, a surface type light receiving element, and a drive circuit for driving or amplifying these elements. Optical switching device. 3. The optical switching apparatus according to claim 1, wherein the wavelength of light received or emitted by the optical switch element array is selectively determined.