Optical switch module and optical relay apparatus and path expansion method that use optical switch module

1. An optical switch module comprising:

N first input ports to which an optical signal is input;

M first output ports from which an optical signal is output;

an M×N switch configured to include N second input ports and M second output ports, and to set an optical path between the N second input ports and the M second output ports, the M second output ports coupling with the M first output ports, respectively;

a test signal input port to which a test signal is capable of being externally input;

an expansion port from which one of the test signal and the optical signal from any one of the N first input ports is output; and

an optical switch configured to selectively connect the test signal and the optical signal from any one of the N first input ports to the expansion port and any one of the N second input ports,

wherein the optical switch is an optical switch of crossbar type, and

wherein a first input port of the N first input ports is switched to a second output port of the M second output ports and a second input port of the N second input ports is switched to a first output port of the M first output ports when the optical signal is transmitted to the expansion port,

wherein both N and M are natural numbers.

2. The optical switch module according to claim 1 ,

wherein the optical switch is a 2×2 optical switch arranged between the N first input ports and the M×N switch; and

wherein a third input port of the 2×2 optical switch couples with any one of the N first input ports, a fourth input port of the 2×2 optical switch couples with the test signal input port, a third output port of the 2×2 optical switch couples with any one of the N second input ports, and a fourth output port of the 2×2 optical switch couples with the expansion port.

3. The optical switch module according to claim 2 ,

wherein the third input port is switched to the third output port and the fourth input port is switched to the fourth output port when the test signal is input to the test signal input port.

4. The optical switch module according to claim 2 ,

wherein the 2×2 optical switch is an optical switch of crossbar type, and

wherein the third input port is switched to the fourth output port and the fourth input port is switched to the third output port when the optical signal from any one of the N first input ports is transmitted to the expansion port.

5. The optical switch module according to claim 1 , further comprising:

a first 2×1 optical switch arranged between the test signal input port and the expansion port,

wherein the optical switch is a second 2×1 optical switch arranged between the N first input ports and the M×N switch,

wherein the first 2×1 optical switch includes a third input port, a fourth input port, and a third output port,

wherein the second 2×1 optical switch includes a fifth input port, a fourth output port, and a fifth output port, and

wherein the third input port couples with the fifth output port, the fourth input port couples with the test signal port, the third output port couples with the expansion port, the fifth input port couples with any one of the N first input ports, and the fourth output port couples with any one of the N second input ports.

6. The optical switch module according to claim 5 ,

wherein the third output port is switched to the fourth input port when the test signal is input to the test signal input port, and

wherein the third output port is switched to the third input port when the input of the test signal to the test signal input port is finished.

7. The optical switch module according to claim 1 ,

wherein the M×N switch includes N (M+1)×1 optical switches coupled with the N first input ports, and

wherein each of the N (M+1)×1 optical switches couples any one of the N first input ports with one of the expansion port and any one of the M second ports.

8. The optical switch module according to claim 7 , further comprising:

a first 2×1 optical switch arranged between the test signal input port and the expansion port,

wherein the first 2×1 optical switch includes a third input port, a fourth input port, and a third output port,

wherein the third input port couples with an M+1st output port of any one of the (M+1)×1 optical switches, the fourth input port couples with the test signal input port, and the third output port couples with the expansion port.

9. The optical switch module according to claim 1 ,

wherein the expansion port couples with a test signal input port of another optical switch module having the same composition as the optical switch module.

10. An optical relay apparatus comprising:

an optical switch module including

N first input ports to which an optical signal is input,

M first output ports from which an optical signal is output,

an M×N switch configured to include N second input ports and M second output ports, and to set an optical path between the N second input ports and the M second output ports, the M second output ports coupling with the M first output ports, respectively,

a test signal input port to which a test signal is capable of being externally input,

an expansion port from which one of the test signal and the optical signal from any one of the N first input ports is output, and

an optical switch configured to selectively connect the test signal and the optical signal from any one of the N first input ports to the expansion port and any one of the N second input ports; and

a wavelength selection switch that selects a wavelength of an optical signal to be transmitted/received to/from a transmission line and to be added from the optical switch module or to be dropped to the optical switch module,

wherein the optical switch is an optical switch of crossbar type, and

wherein a first input port of the N first input ports is switched to a second output port of the M second output ports and a second input port of the N second input ports is switched to a first output port of the M first output ports when the optical signal is transmitted to the expansion port,

wherein both N and M are natural numbers.