Patent ID: 6084704
Filing Date: 2000-07-04
Classification: H04B

Abstract:
An optical signal amplification device, comprising:a substantially unidirectional first amplification path for amplifying an in-band communications signals wavelength band, .DELTA..lambda..sub.1 ; anda substantially unidirectional second amplification path for amplifying an in band communications signals wavelength band, .DELTA..lambda..sub.2 different from .DELTA..lambda..sub.1,wherein at least one of the first and second amplification paths includes a wavelength selective insertion loss having a selected location along said amplification path such that said insertion loss substantially blocks an out-of-band optical communication signal and provides a pre-insertion loss gain and a post-insertion loss gain for an in-band optical communication signal, obtaining at least one of a target noise figure performance and a target output power performance from the device and satisfying the following relationshipG.sub.inB +R.sub.T07 +G.sub.outB +L<P, whereP is a critical crosstalk pain limit, G.sub.inB is gain for in-band wavelength band, G.sub.outB is gain for out-of band wavelength band, R.sub.TOT is total loss due to reflection R.sub.TOT .ltoreq.0 dB, and L is additional loss including said insertion loss located along said amplification path.