Patent ID: 6917732

Claim:
An optical apparatus comprising: a substrate having a first end portion and an opposing second end portion; a first optical function device, a second optical function device, and a third optical function device arranged in order on the substrate, the first optical function device having an input end and an output end respectively at the first end portion and the second end portion of the substrate, and the second optical function device and the third optical function device each having an input end input and an output end respectively at the second end portion and the first end portion of the substrate; means for connecting the output end of the first optical function device at the second end portion of the substrate with the input end of the second optical function device at the second end portion of the substrate; means for connecting the output end of the second optical function device at the first end portion of the substrate with the input end of the third optical function device at the second end portion of the substrate; and a polarization beam splitter connecting the input end of the first optical function device at the first end portion of the substrate with the output end of the third optical function device at the first end portion of the substrate.