Schematic of phase-sensitive OCT: SS, swept source; C (A:B), fiber coupler with A to B coupling ratio; AT, attenuator; OD, optical delay line; PC, polarization controller; CIR, circulator; COL, collimator; SM, scanning mirror; OL, objective lens; BPD, balanced photodetector; FPGA, FPGA module; HOST, host computer; SPK; speaker. Blue lines: optical connections. Purple lines: electrical SMA connections. Black lines: electrical BNC connections.