Gain saturation dependence on signal wavelength in a travelling-wave semiconductor laser amplifier

Gain saturation dependence on signal wavelength in a 1.5 ¿m InGaAsP travelling-wave semiconductor laser amplifier is experimentally studied. Saturation output powers were 6.9dBm, 8.3dBm and 10.6dBm for signal wavelengths of 1490 nm, 1510 nm and 1540 nm, respectively. This saturation dependence on wavelength, i.e. higher saturation output power for longer signal wavelength, results from signal gain peak shift towards longer wavelength with increasing input power.