Optical coherence imaging systems having a reduced effective linewidth and methods of using the same

A frequency domain optical coherence imaging system, comprising:

• an optical source, wherein the optical source comprises a broadband source;
• an optical detector;
• and
• an optical transmission path between the optical source and the optical detector that reduces an effective linewidth of the imaging system, wherein the optical transmission path includes:
• an optical splitter having a first side including a port coupled to a source arm and a port coupled to a detector arm and a second side having a port coupled to a reference arm and a port coupled to a sample arm and a periodic optical filter;
• wherein the frequency domain optical coherence imaging system further comprises:
• the periodic optical filter positioned in the detector arm between the optical splitter and the optical detector, the optical detector comprising a first spectrometer and a second spectrometer and wherein the periodic optical filter has a first output coupled to the first spectrometer and a second output coupled to the second spectrometer, the periodic optical filter comprising an interleaver having a finesse of two;
• the periodic optical filter positioned in the detector arm between the optical splitter and the optical detector, the optical detector comprising a first spectrometer and a second spectrometer and wherein the periodic optical filter has a first output coupled to the first spectrometer and a second output coupled to the second spectrometer, the periodic optical filter comprising an interleaver having a finesse of greater than two;
• the periodic optical filter positioned in the detector arm between the optical splitter and the optical detector, the optical detector comprising a first spectrometer and a second spectrometer and wherein the periodic optical filter has a first output coupled to the first spectrometer and a second output coupled to the second spectrometer, the periodic optical filter having a free spectral range that substantially matches a pixel spacing of the first and second spectrometer;
• the periodic optical filter positioned in the detector arm between the optical splitter and the optical detector, wherein the optical detector comprises a spectrometer and wherein the frequency domain optical coherence imaging system further comprises an optical switching device in the detector arm that selectively couples a plurality of outputs of the periodic optical filter to the spectrometer;
• the periodic optical filter positioned in the detector arm between the optical splitter and the optical detector wherein the periodic optical filter comprises a cascaded plurality of optical filters and wherein the optical detector comprises a first and a second spectrometer and wherein the cascaded periodic optical filters have a first output coupled to the first spectrometer and a second output connected to the second spectrometer, the first output comprising a first set of outputs from one of the cascaded periodic optical filters and the second output comprising a second set of outputs from another of the cascaded periodic optical filters and wherein the frequency domain optical coherence imaging system further comprises a first optical switching device coupling the first set of outputs to the first spectrometer and a second optical switching device coupling the second set of outputs to the second spectrometer;
• and/or
• the periodic optical filter comprising a first periodic optical filter and wherein the system further comprises a second periodic optical filter and wherein the first periodic optical filter is positioned in the reference arm or the sample arm and the second periodic optical filter is positioned in a different arm of the system, wherein the first and second periodic optical filters are interleavers having a substantially same free spectral range (FSR) and a finesse of at least two and wherein the first and second periodic optical filters are offset by about one quarter of the FSR.