Patent ID: 6563977
Filing Date: 2003-05-13
Classification: G02B

Abstract:
An optical multiplexing and demultiplexing device comprising:fiber mounting means for securing a plurality of optical fibers each terminating in a fiber end, at least one of said fiber ends radiating a corresponding input beam having a polarization state defined by a polarization plane orientation, and at least one of said fiber ends for receiving an output beam; collimating and focusing means having a focal length associated therewith, and providing collimation of said input beam, and focusing of said output beam; diffraction means including at least one transmissive diffractive element for diffracting optical beams passing therethrough, each said diffractive element having an associated diffraction efficiency that depends on the polarization state of a light beam passing therethrough; a reflective element; polarization rotating means disposed between said reflective element and said diffraction means for rotating the polarization plane orientation of a light beam passing through said rotating means; and wherein a particular input beam having a first polarization state is transmissively diffracted a first time by said diffraction means in accordance with a first diffraction efficiency that depends on said first polarization state, passed through said polarization rotating means a first time, reflected by said reflective element back to said polarization rotating means, passed through said polarization rotating means a second time and thereby rotated into a second polarization state, and transmissively diffracted a second time by said diffraction means in accordance with a second diffraction efficiency that depends on said second polarization state, whereby the device provides a total diffraction efficiency that is substantially insensitive to the polarization state of said input beam.