Patent ID: 7106501

Claim:
A method of amplifying an optical signal, the signal being delivered by either a laser or an optical amplifier, and the optical signal having a power, a center wavelength and a bandwidth, the method comprising the steps of: providing a length of amplifier fiber; propagating the optical signal along said amplifier fiber in a forward direction therein while coupling optical pump light into said optical fiber to energize said optical fiber and provide optical gain, thereby amplifying the optical signal and generating amplified spontaneous emission (ASE) propagating in forward and reverse directions in said amplifier fiber, said ASE having a bandwidth substantially greater than the bandwidth of the optical signal; following said forward direction propagation in said amplifier fiber, reflecting said amplified optical signal from a first fiber Bragg grating in a reverse direction in said amplifier fiber while transmitting a substantial portion of said forward-propagating ASE through said first fiber Bragg grating, wherein the signal power is such that said amplifier fiber has substantially greater optical gain for said amplified optical signal in said forward direction therethrough than in said reverse direction therethrough; providing a length of a non-amplifying optical fiber; propagating said reflected amplified signal and reverse-propagating ASE from said amplifying fiber along said non-amplifying fiber in a forward direction therein; and following said forward direction propagation in said non-amplifying fiber, reflecting said reflected amplified optical signal from a second fiber Bragg grating to provide a twice-reflected amplified optical signal propagating in a reverse direction in said non-amplifying fiber while transmitting a substantial portion said reverse-propagating ASE through said second fiber Bragg grating.