Patent ID: 7139119

Claim:
A fiber optical amplifier for amplifying an optical signal, comprising: an amplifier fiber having an input end for receiving said optical signal, said amplifier fiber terminating in a first fiber Bragg grating; a source of optical pump light connected to said amplifier fiber for energizing said amplifier fiber; a non-amplifying fiber having an input end, said non-amplifier fiber terminating in a second fiber Bragg grating; and wherein when optical pump light from said source thereof is delivered to said amplifier fiber, said optical signal is amplified when propagating in a forward direction and after being reflected by the Bragg grating, amplified in the reverse direction, with the amplification in the reverse direction being less than in the amplification in said forward direction, and wherein amplified spontaneous emission (ASE) is generated in said amplifier fiber propagating in said forward and reverse directions therein, with the forward propagating ASE being substantially transmitted out of the amplifier fiber by said first fiber Bragg grating, and with the amplified signal and said reverse propagating ASE being coupled into the non-amplifying fiber, with the reverse propagating ASE being substantially transmitted out of the non-amplifying fiber by said second fiber Bragg grating and wherein the amplified signal is coupled out of the non-amplifying fiber after reflection from the second Bragg grating.