Amplification of a narrow-band optical signal in an active waveguide

An investigation was made of amplification in an optically pumped single-mode planar dielectric waveguide activated with rhodamine B. Radiation emitted from a distributed–feedback laser of spectral width 0.2 run was used as the input signal. Measurements were made of the power and spectrum of the output signal as a function of the input signal level. A gain of 100 was obtained for the ratio of the signal to background exceeding 10. The method for filtering out the spontaneous background was considered.