Clarification of the degradation modes of an InP-based semiconductor MZ modulator

We clarified the degradation modes of an InP-based semiconductor optical Mach-Zehnder modulator (MZM) using high-power light-injected accelerated aging tests. Degradation clearly occurred at the light injected side of the edge on the electric field applied region. We found that the degradation threshold depends strongly on temperature, wavelength and bias voltage. By correlating these parameters, we propose a degradation model based on the concentration of the optical absorption current, which depends on the optical absorption coefficient. By employing the degradation model, we obtained the degradation activation energy for a semiconductor MZM for the first time, and the value was 0.45 eV. These results indicate that a semiconductor MZM is sufficiently reliable for use in actual optical communication systems.