APPLICATION OF THE SPECTRAL INDEX METHOD TO LASER-DIODE DESIGN

The spectral index method (SIM) is compared to the effective index met hod (ELM) and the beam propagation method (BPM) for the calculation of the optical mode index and mode profile in a prototypical distributed feedback (DFB) rib waveguide laser diode. Modal index is shown to be insufficient as a metric of comparison, so in addition to n(mode), the quantum well filling factor Gamma and grating coupling coefficient ka ppa are included in the metric for comparison, SIM is found to yield s uperior results to EIM and to give results comparable to BPM almost tw o orders of magnitude faster.