Polarization independent optical isolator

A polarization independent optical isolator is disclosed which uses a single birefringent plate. A pair of stacked reciprocal rotators, a Faraday rotator, and reflector are positioned in tandem adjacent to the birefringent plate. In the forward (transmitting) direction, a lightwave signal exiting an optical fiber is split into a pair of orthogonal rays by the birefringent plate. The orthogonal rays then pass through a first reciprocal rotator and the Faraday rotator. The rotated rays are then redirected by the reflector back through the Faraday rotator. After passing through the second reciprocal rotator, the orthogonal rays re-enter the same birefringent plate where they are recombined and launched in an output fiber. Since a Faraday rotator is a non-reciprocal device, any signal traveling through the isolator in the reverse (isolation) direction will be split on both passes through the birefringent plate such that neither will intercept the input fiber.