Patent ID: 8554023

Claim:
A method for effecting self-interference of an optical signal, the method comprising: splitting said optical signal into a first and a second light portion; coupling said first and second light portions to a loop comprising a plurality of segments of polarization-maintaining fiber such that said first and second light portions propagate concurrently in mutually opposite directions in said loop; oppositely propagating said first and said second light portions along respective mutually orthogonal polarization axes on at least a first of said segments of polarization-maintaining fiber of said loop, such that birefringence of said at least a first of said segments where the light portions propagate on mutually orthogonal polarization axes provides a differential path length; on a second of said segments of polarization-maintaining fiber of said loop, propagating said first and second light portions along a same polarization axis; and interfering together the propagated light portions to provide a Mach-Zehnder interferometer having said differential path length.