Patent ID: 6900938

Claim:
An interleaver comprising: a birefringent device assembly comprising at least one spatial birefringent device, the birefringent device assembly providing two interim output components; a reflector configured to direct the two interim output components from the birefringent device assembly back through the birefringent device assembly; wherein the spatial birefringent device consists of: a polarization beam splitter to separate an optical beam into two orthogonally polarized components; a first polarization rotator and a first reflector to control the propagation of one of the two orthogonally polarized components; a second polarization rotator and a second reflector to control the propagation of the other one of the two orthogonally polarized components; wherein the first polarization rotator, the first reflector, the second polarization rotator, the second reflector and the polarization beam splitter are configured such that each of the two orthogonally polarized components travels along separate paths of different optical path lengths and when the two orthogonally polarized components recombine at the output of the spatial birefringent device, a phase delay between the two orthogonally polarized components is achieved.