A technique, base don quantum well (QW) intermixing, has been developed for the post growth, spatially selective tuning of the QW bandgap in a semiconductor laser structure. High energy ion implantation is used to create a large number of vacancies and interstitials in the device. During high temperature processing, these defects enhance the intermixing of the QW and the barrier materials while being annealed out, producing a blue shift of the QW bandgap. Increases in bandgap energy of greater than 10 nm at 1.55 micrometers in InGaAs/InGaAsP/InP structures can be achieved. Absorption spectroscopy in the waveguide geometry is used to quantify the losses in the structure. Using a simple masking scheme to spatially modify the defect concentration, different regions of a wafer can be blue shifted by different amounts. This allows the integration of many different devices such as lasers, detectors, modulators, amplifiers and waveguides on a single wafer using only a single, post-growth processing step. The performance of both passive and active devices produced using this technique will be described, as well as the practicality of this technique in the production of photonic integrated circuits.
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