| 摘要 |
An apparatus includes a polarization beam splitter (8), at least two reflectors (10, and 12 or 14) and first and second polarization rotation devices (20, and 60 or 80). The polarization beam splitter (8) and the at least two reflectors (20, and 60 or 80) are arranged in a loop that is capable of propagating a clockwise signal component and a counterclockwise signal component. The first polarization rotation device (20) is located in the loop between the polarization beam splitter (8) and a first reflector (10) of the at least two reflectors. The second polarization rotation device (60 or 80) is located in the loop between the polarization beam splitter (8) and an additional reflector (12 or 14) of the at least two reflectors. The first polarization rotation device includes a serial arrangement comprising a reciprocal rotator (22) and a nonreciprocal rotator (24). <IMAGE> |
