Patent ID: 6972897

Claim:
A long-band Erbium doped-fiber amplifier comprising: (a) a first Erbium doped fiber having a first predetermined length, coupled to a first pumping light source through a first wavelength-selective coupler, for amplifying a C-band optical signal via a first pumping light source; (b) a second Erbium doped fiber having a second predetermined length for amplifying an L-band optical signal via a second pumping light source; (c) a feedback loop for recycling a specific C-band wavelength generated in the amplification of the first Erbium doped fiber as the second pumping light source of the L-band optical signal; (d) a tap coupler disposed between the first and second Erbium doped fibers for dividing an optical-power output amplified in the first Erbium doped fiber, for supplying a predetermined ratio of the optical power output to the second Erbium doped fiber, and for supplying the residual optical power output to the feedback loop; and, (e) a second wavelength-selective coupler for coupling the output transmitted from the tap coupler to the first Erbium doped fiber.