T. Keating et al., OPTICAL GAIN AND REFRACTIVE-INDEX OF A LASER-AMPLIFIER IN THE PRESENCE OF PUMP LIGHT FOR CROSS-GAIN AND CROSS-PHASE MODULATION, IEEE photonics technology letters, 9(10), 1997, pp. 1358-1360
The wavelength dependent changes in optical gain and refractive index
in a Fabry-Perot semiconductor optical amplifier are measured for vari
ous detunings of the pump wavelength from the quasi-Fermi level separa
tion. The refractive index change is nearly constant over a very large
wavelength range. We also present data for the linewidth enhancement
factor due to optical injection. Estimates of the carrier densities an
d stimulated recombination rates are made using our optical gain model
based on realistic band structure calculations for a strained quantum
-well laser. Our results are very useful for ultra-broad-band waveleng
th conversion by cross-gain and cross-phase modulation (XGM, XPM).