Patent ID: 7877011

Claim:
A path switching apparatus of optical signals using optical circulators for outputting the optical signals inputted from a first port to a second port, from said second port to a third port, and from said third port to said first port, respectively, comprising: 2k first optical switches each of which has a fourth port, a fifth port, and a sixth port and can set a path of the optical signal between said fourth port and an arbitrary one of said fifth port and said sixth port; a second optical switch and a third optical switch each of which has k seventh ports and k eighth ports and arbitrarily connects said seventh port and said eighth port in a one-to-one corresponding relational manner; a fourth optical switch which has a ninth port having k ports and a tenth port having k ports and arbitrarily connects said ninth port and said tenth port in a one-to-one corresponding relational manner; k first optical circulators in each of which said second port is connected to the seventh port of said second optical switch in a one-to-one corresponding relational manner and said third port is connected to the eighth port of said second optical switch in a one-to-one corresponding relational manner; k second optical circulators in each of which said second port is connected to the seventh port of said third optical switch in a one-to-one corresponding relational manner and said third port is connected to the eighth port of said third optical switch in a one-to-one corresponding relational manner, wherein with respect to k of said first optical switches, said fifth port and a first port of said first optical circulator are connected in a one-to-one corresponding relational manner and said sixth port is connected to one of said ninth ports of said fourth optical switch in a one-to-one corresponding relational manner, and with respect to remaining k of said first optical switches, said fifth port and a first port of said second optical circulator are connected in a one-to-one corresponding relational manner and said sixth port is connected to one of said tenth ports of said fourth optical switch in a one-to-one corresponding relational manner.