Fiber optic inter-mode coupling single side band frequency shifter.

摘要

An optical fiber (300) is subjected to a series of traveling flexural waves or microbends propagating along a length of the fiber. At least a portion of an optical signal propagating within the optical fiber in a first propagation mode is coupled to a second propagation mode. The optical signal in the second propagation mode has a frequency which is equal to either the sum of or the difference between the frequency of the optical signal in the first propagation mode and the frequency of the traveling flexural waves or microbends. The frequency of the optical signal in the second propagation mode is shifted upward or downward from the frequency of the optical signal in the first propagation mode as determined by the direction of propagation of the first optical signal with respect to the direction of propagation of the traveling flexural waves or microbends, and as also determined by whether the phase propagation velocity of the optical signal in the first propagation mode is greater than or less than the propagation velocity of the optical signal in the second propagation mode.