Patent ID: 6498676
Filing Date: 2002-12-24
Classification: G02B,H01S,H04B

Abstract:
A variable slope optical filter for in-line use with an optical amplifier signal comprising:a filter element having at least two regions, each region of the filter element having a different amplitude response as a function of wavelength wherein undispersed light passes through at least a portion of one of the regions, the filter element being disposed at an input side, an output side, or within the optical amplifier, the filter element having a wavelength response that is substantially linear in slope within a band of operation wavelengths of the amplifier, within a substantial portion of an operating wavelength band the slope of the filter element in said band of wavelengths being between zero and only one of a positive or negative number, the filter element for passing a band of wavelengths having a centre wavelength &lgr;c and having an amplitude response that has an opposite and counter slope as a function of wavelength to that of a gain tilt of the amplifier within the band of operation wavelengths; and, a means for providing relative movement between the filter element and the optical amplifier signal to vary the slope of the amplitude response of the filter element by means of varying the amplitude wavelength response of the filter element.