Patent ID: 7535639

Claim:
A device, comprising: a first polarization beam splitter (PBS), a second PBS, and a reflector arranged to form an optical system, said first PBS positioned to receive an input optical beam with a coherent length and to split the input optical beam into a first beam and a second beam polarized orthogonal to said first beam, said reflector positioned to reflect said first beam to said second PBS to cause an optical path difference between said first and said second beams at said second PBS to be greater than said coherent length, and said second PBS positioned to receive and combine said first and said second beams to produce an output beam; a first polarization beam displacer in an optical path of the input optical beam to separate the input beam into two orthogonally polarized input beams to be received by said first PBS; and a second polarization beam displacer in an optical path of the output beam to combine two orthogonally polarized beams from said PBS into said output beam.