Temperature and spatial hole burning effects in semiconductor lasers and integrated optical devices

The effects of temperature and spatial hole burning are investigated in long-wavelength InP-based lasers and integrated optical devices, including Fabry-Perot (FP) lasers, distributed-feedback (DFB) lasers, and integrated electroabsorption modulator with DFB lasers (EML). First, the temperature dependence of bulk InGaAsP semiconductor laser diodes is analyzed using a consistent method involving gain and spontaneous emission measurements to isolate the temperature-sensitive effects. Second, longitudinal spatial hole burning is examined theoretically and experimentally in both Fabry-Perot and index-coupled distributed-feedback lasers. The photon density profiles are calculated and compared with the carrier density profiles extracted from spontaneous emission measurements. The facet reflection coatings have a large impact on the spatial hole burning in laser diodes. Next, a longitudinal model using the transfer-matrix method and coupled-mode theory is developed for integrated devices. The model is applied to the characterization of an integrated electroabsorption modulator with a distributed-feedback laser. It is shown that the adiabatic wavelength chirping of the EML is very sensitive to the optical feedback from the facets. Finally, a four-channel DFB laser array integrated with a semiconductor optical amplifier and electroabsorption modulator is designed and fabricated. Tunable three-electrode curved-waveguide DFB lasers are used to generate the multiple wavelengths. The output power per channel is as high as 2 mW, and the device operates successfully at 2.5 Gbit/s.