Effective phase and group indices for In1−xGaxP1−yAsy/InP waveguide structures

Effective phase and effective group indices for the complete wavelength range of the In1−xGaxP1−yAsy/InP system have been theoretically determined for symmetrical waveguide structures. A comparison between our theory and experimental data gained on a large number of our own lasers as well as on data from literature shows a very good agreement. This result confirms our calculation and rules out the dispersion behavior near the band-gap energy of the models of Afromowitz [Solid-State Commun. 15, 59 (1974)] and Adachi [J. Appl. Phys. 53, 5863 (1982)]. The results of our calculation allow us to determine the active layer thickness of DH lasers from the knowledge of the mode spacing and the laser length.