Patent ID: 6501594
Filing Date: 2002-12-31
Classification: H01S,H04B

Abstract:
A fiber amplifier apparatus, comprising:an optical fiber amplifying light signals; a first pump laser diode generating pumping light and being positioned upstream of said fiber; a second pump laser diode generating pumping light and being positioned downstream of said fiber; a first plurality of wavelength selective couplers providing the pumping light from said first and second diodes to said fiber; an output terminal being positioned downstream of said fiber; an input terminal being positioned upstream of said fiber and output terminal, receiving an input signal light, conveying said input signal light downstream toward said output terminal; a first plurality of optical isolators including at least a first isolator and a second isolator, said first isolator intercepting upstream propagation of light and being positioned adjacent to and downstream of said input terminal, said second isolator intercepting upstream propagation of light and being positioned adjacent to and upstream of said output terminal; a feedback loop guiding at least one selected from among a seed beam and an amplified spontaneous emission to be incident to said fiber, thereby producing amplification to L-band optical signals, said feedback loop having a first terminal and a second terminal, said first terminal being positioned upstream of said first pump laser diode and downstream of said first isolator, said second terminal being positioned downstream of said second pump laser diode and upstream of said second isolator; a second plurality of wavelength selective couplers guiding at least one selected from among the seed beam and the amplified spontaneous emission to be incident to said feedback loop; a filter being disposed on said feedback loop, filtering specified wavelengths of at least one selected from among the seed beam and the amplified spontaneous emission; an optical attenuator attenuating a strength of a light signal in said feedback loop, said optical attenuator being positioned in said feedback loop between said filter and said second terminal; and an additional optical isolator being positioned in said feedback loop between said filter and said first terminal, said additional optical isolator intercepting propagation of at least one selected from among the seed beam and the amplified spontaneous emission.