Patent ID: 6104528
Filing Date: 2000-08-15
Classification: H01S,H04B

Abstract:
An optical fiber amplifier for achieving high gain of a small signal comprising:a pump laser diode (LD) for applying pumping light to amplify incident signal light;a wavelength division multiplexer (WDM) for coupling the incident signal light and the pumping light output from the pump LD into an optical fiber;a fiber amplification medium for amplifying the incident signal light output from the WDM using the pumping light of the pump LD, and feedback signal light reentering the fiber amplification medium from a coupler;a loop mirror coupler attached to the fiber amplification medium, for reflecting the incident signal light already amplified by the fiber amplification medium, in a loop and sending reflected signal light back to the fiber amplification medium;a filter in the coupler for suppressing amplified spontaneous emission (ASE) to obtain higher gain; anda circulator in front of the WDM, receiving weak incident signal light and transmitting the incident signal light to the WDM, and outputting the feedback signal light, amplified by the fiber amplification medium, and passed through the WDM.