Study of Semiconductor Microring Lasers for use in Wavelength Division Multiplexing (WDM) Telecommunication Networks

In this thesis, the optical characteristics of all-active microring resonators as lasers are studied. The structure of a semiconductor microring laser coupled to a bus waveguide is investigated. The scope of the study is to examine the microring’s laser operation and also emphasize the influence of the key design parameters on single mode and/or unidirectional operation, both being of major concern for future microring-based lightwave system applications. An analytic multimode model for the simulation of 1.55 μm InGaAsP-InP microring laser’s dynamic properties is presented. Different operation regimes are observed. The boundaries of the operating regimes are investigated with respect to the ring current level, the bus waveguide reflectivity and the ring radius. Moreover the Relative Intensity Noise spectra are studied. In addition an experimental verification of the numerical results is presented. A complete study is performed varying the ring radius and the microring’s bias current. Further, the mode hopping phenomena are measured and presented through the time traces spectra and the Relative Intensity Noise spectra. For the first time an alternative method of controlling the bus waveguide facet residual reflectivity by varying the bus waveguide’s current is experimentally demonstrated.