Patent ID: 7106512

Claim:
An optical device comprising: an optics system comprising an input to receive optical signals in an incoming direction and an output to selectively transmit a selected optical signal of said optical signals in an outgoing direction, said optics system being configured to selectively rotate one of the polarization components of each of said optical signals in said incoming direction to a first polarization state; an optical unit optically coupled to said optics system, said optical unit being configured to laterally displace and rotate said polarization components of said selected optical signal such that said polarization components of said selected optical signal in said outgoing direction are in said first polarization state, said optical unit comprising a first polarizing beamsplitter, a second polarizing beamsplitter and a wave plate positioned such that said polarization components of said selected optical signal in said outgoing direction are selectively transmitted though said wave plate; and a diffraction grating positioned between said optics system and said optical unit to diffract said polarization components of said selected optical signal in said incoming and outgoing directions, said polarization components of said selected optical signal being in said first polarization state in both said incoming and outgoing directions at said diffraction grating.