Abstract: An optical amplifier has two amplifying sections formed in a semiconductor structure. The two amplifying sections have different ratios of gain for two polarization states (e.g., TE and TM). Thus the amplifier as a whole has a gain ratio determined by the gains of the two amplifying sections. The two amplifying sections are separately electronically controllable so as to control the gains of the two amplifying sections and thus the gain ratio of the amplifier as a whole. Such an amplifier can be made by quantum well intermixing.
Abstract: An optical amplifier has two amplifying sections formed in a semiconductor structure. The two amplifying sections have different ratios of gain for two polarization states (e.g., TE and TM). Thus the amplifier as a whole has a gain ratio determined by the gains of the two amplifying sections. The two amplifying sections are separately electronically controllable so as to control the gains of the two amplifying sections and thus the gain ratio of the amplifier as a whole. Such an amplifier can be made by quantum well intermixing.
Abstract: A laser has a spatially varying absorption spectrum formed in a monolithic InGaAsP structure whose quantum well active structure has modified effective bandgap properties. The spatially varying emission spectrum allows emission at multiple wavelengths or emission in a broad band. The effective bandgap properties can be modified by rapid thermal annealing to cause the diffusion of defects from one or two InP defect layers into the quantum well active structure. The laser can be implemented variously as a Fabry-Perot laser and a laser array.
Abstract: In a semiconductor laser, non-disordered quantum well active region functions as a lasing region. Surrounding the non-disordered quantum well active region is a disordered quantum well active region which prevents diffusion of injected carriers from the non-disordered quantum well active region or provides a lateral heterobarrier. The disordered quantum well active region is formed by rapid thermal annealing in which defects from one or two InP defect layers diffuse into the parts of the quantum well active region to be disordered.