Interferometric determination of the linewidth enhancement factor of a 1.55µm GaInAsP optical amplifier

J. F. Ehrhart, A. Villeneuve, G. Assanto, G. I. Stegeman, B. Mersali, A. Accard, G. Gelly, and B. Fernier

Appl. Phys. Lett. 58, 816-818 (1991)

Abstract:

We report on the measurement of the small signal gain and index variation of a GaInAsP semiconductor optical amplifier as a function of the injected current in the wavelength range 1.53-1.58 µm. Employing interferometry to evaluate the index changes, we have determined that the linewidth enhancement factor varies from 9 to 4 for photon energies ranging from below to above the band gap, respectively.