Patent ID: 7206479

Claim:
An optical device, comprising: a first waveguide and at least a second waveguide at a first end of the device; a coupling module comprising at least a first lens; and a folded optical system with bi-directional, polarization-dependent free-space paths that couple the first waveguide and the at least a second waveguide, the folded optical system including a birefringent path separator and a reflecting element, an optical path for unpolarized light from the first waveguide passing through the birefringent path separator where the unpolarized light is separated into two orthogonal polarization components, the separated orthogonal polarization components propagating along separated polarized optical pathhs to the reflecting element and being reflected by the reflecting element back through the birefringent path separator, only one of the polarized optical paths leading to the second waveguide; wherein light passing between one of the first waveguide and the at least a second waveguide to the folded optical system passes through the first lens and light passing from the folded optical system to the other of the first waveguide and the at least a second waveguide passes trough the first lens.