Patent ID: 7813040

Claim:
A multi-stage multi-port optical isolator comprising: a plurality of input ports and a plurality of output ports aligned along a same line; a first isolating stage and a second isolating stage, wherein the first isolating stage is coupled to the second isolating stage through a Porro prism disposed at an end of the multi-stage multi-port optical isolator, the first and second isolating stages each having: a) means for splitting beams of light passing therethrough into sub-beams in a polarization dependent manner b) non-reciprocal rotating means for rotating light passing therethrough in a polarization dependent manner, and c) means for combining light that has been split into sub-beams, wherein light passing through the Porro prism received from the first isolating stage is directed to the second isolating stage; and wherein components of the multi-stage multi-port optical isolator are configured to direct light passing through the multi-port optical isolator from the plurality of input ports to the plurality of output ports, wherein the non-reciprocal rotating means in each isolating stage includes a waveplate and a Faraday rotator, wherein one of the first stage and second stage isolators further comprises a second waveplate configured to receive a single beam of light from any of the input ports and wherein the second waveplate is disposed to receive two sub-beams when a single beam of light is launched into any of the output ports, and wherein the second wave plate is disposed and oriented so as to interchange the polarization states of the two sub-beams passing therethrough.