Patent ID: 7280221

Claim:
An interferometer, comprising: a light source; an isolator coupled to the light source; polarization dependent optics coupled to the isolator; a reference arm connected to the polarization dependent optics; a sample arm connected to the polarization dependent optics; and one or more optical detectors coupled to the polarization dependent optics, wherein the polarization dependent optics couples light into the reference arm and the sample arm, receives reflected light from the reference arm and the sample arm, and provides light to the one or more optical detectors such that a polarization independent optical signal can be formed in an optical signal processing unit coupled to the one or more optical detectors, wherein the isolator blocks reflected light from the reference arm and the sample arm from entering the light source, wherein the isolator comprises a polarization dependent beam splitter, the polarization dependent beam splitter coupled to receive light from the light source and provide a beam of a first polarization, and wherein the polarization dependent optics comprises: a Faraday rotator and a wave plate coupled to receive the beam of the first polarization and output the beam of the first polarization; a second polarization beam splitter coupled to receive the beam of the first polarization from the Faraday rotator and the wave plate and transmit the beam of the first polarization; and a beam splitter coupled to receive the beam of the first polarization from the second polarization beam splitter, couple the beam of the first polarization in the sample arm and the reference arm, receive a reflected beam from the sample arm and the reference arm, and combine the reflected beams from the sample arm and the reference arm into a combined reflected beam, wherein, the combined reflected beam is separated into a combined reflected beam of the first polarization and a combined reflected beam of a second polarization by the second polarization beam splitter, the combined reflected beam of the second polarization being coupled to one of the one or more optical detectors, and wherein the combined reflected beam of the first polarization is polarization rotated to the second polarization by the Faraday rotator and the wave plate and coupled into another of the one or more optical detectors by the polarization beam splitter.