Bidirectional monitor module, optical module, optical add-drop multiplexer, and optical system

1. A bidirectional monitor module, comprising:

a 2×2 optical coupler configured to output input light that is input from a first port to a second port and drop the input light input from the first port to a third port and also output input light that is input from the second port to the first port and drop the input light input from the second port to a fourth port;

an optical output unit configured to output one of light that is dropped and output from the third port and light that is dropped and output from the fourth port, the optical output unit being a 2×1 optical coupler configured to multiplex input light input from one input port with input light input from another input port to be output; and

a monitor unit configured to monitor optical power of the light output from the optical output unit.

2. The bidirectional monitor module according to claim 1 ,

wherein the input light is wavelength division multiplexed light obtained by multiplexing a plurality of different wavelengths with each other.

3. The bidirectional monitor module according to claim 1 ,

wherein a dropping ratio of the 2×2 optical coupler from the first port to the second port is higher than a dropping ratio of the 2×2 optical coupler from the first port to the third port, and a dropping ratio of the 2×2 optical coupler from the second port to the first port is higher than a dropping ratio of the 2×2 optical coupler from the second port to the fourth port.

4. A bidirectional monitor module, comprising:

a first 2×2 optical coupler configured to output input light that is input from a first port to a second port and drop the input light input from the first port to a third port and also output input light that is input from the second port to the first port and drop the input light input from the second port to a fourth port;

a first optical output unit configured to output one of light that is dropped and output from the third port and light that is dropped and output from the fourth port;

a second 2×2 optical coupler configured to output input light that is input from a fifth port to a sixth port and drop the input light input from the fifth port to a seventh port and also output input light that is input from the sixth port to the fifth port and drops the input light input from the sixth port to an eighth port;

a second optical output unit configured to output one of light that is dropped and output from the seventh port of the second 2×2 optical coupler and light that is dropped and output from the eighth port of the second 2×2 optical coupler;

a 2×1 optical switch configured to selectively output one of the light output from the first optical output unit and the light output from the second optical output unit; and

a monitor unit configured to monitor optical power of the light output from the light output from 2×1 optical switch.

5. The bidirectional monitor module according to claim 4 ,

wherein each of the first optical output unit and the second optical output unit is a 2×1 optical coupler configured to multiplex input light input from one input port with input light input from another input port to be output.

6. The bidirectional monitor module according to claim 4 ,

wherein each of the first optical output unit and the second optical output unit is a 2×1 optical switch configured to selectively output one of input light input from one input port and input light input from another input port.

7. The bidirectional monitor module according to claim 4 ,

wherein a dropping ratio of the first 2×2 optical coupler from the first port to the second port is higher than a dropping ratio of the first 2×2 optical coupler from the first port to the third port, and a dropping ratio of the first 2×2 optical coupler from the second port to the first port is higher than a dropping ratio of the first 2×2 optical coupler from the second port to the fourth port, and

wherein a dropping ratio of the second 2×2 optical coupler from the fifth port to the sixth port is higher than a dropping ratio of the second 2×2 optical coupler from the fifth port to the seventh port, and a dropping ratio of the second 2×2 optical coupler from the sixth port to the fifth port is higher than a dropping ratio of the second 2×2 optical coupler from the sixth port to the eighth port.

8. An optical module, comprising:

a bidirectional monitor module comprising:

a 2×2 optical coupler configured to output input light that is input from a first port to a second port and drop the input light input from the first port to a third port and also output input light that is input from the second port to the first port and drop the input light input from the second port to a fourth port,

an optical output unit configured to output one of light that is dropped and output from the third port of the 2×2 optical coupler and light that is dropped and output from the fourth port of the 2×2 optical coupler, the optical output unit being a 2×1 optical coupler configured to multiplex input light input from one input port with input light input from another input port to be output, and

a monitor unit configured to monitor optical power of the light output from the optical output unit;

an optical switch configured as a single-input multi-output wavelength selection optical switch and also configured as a multi-input single-output wavelength selection optical switch; and

an optical multiplexer and demultiplexer configured as a single-input multi-output optical splitter and also configured as a multi-input single-output optical coupler, wherein

the bidirectional monitor module that monitors at least one of input light input to the optical switch or the optical multiplexer and demultiplexer and output light output from the optical switch or the optical multiplexer and demultiplexer.