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Abstract The effect of proton implantation as isolation implant and subsequent annealing on the optical absorption and electrical resistivity of low-bandgapp-GaSb is reported. The measured transmittance spectra indicates that implantation creates a distribution of energy levels extending into the bandgap. Electrical measurements show that the average sheet resistance of the implanted layer increases only by an order of magnitude from its pre-implantation value at a proton dose of ∼10¹³cm⁻²followed by 200 °C annealing. It is also shown that annealing reduces the implantation-induced optical absorption while still retaining a high electrical resistivity. 

Light at mid-wave infrared- as well as visible-wavelengths are widely used in biophotonic applications with the promise of much improved healthcare. This talk will review on recent progress made at OSU towards developing photonic integrated circuit technologies at these wavelengths. 

Abstract In this paper, we report, for the first time, a theoretical study on passive photonic devices including optical power splitters/combiners and grating couplers (GCs) operating at non-telecom wavelengths above 2 µ m in a monolithic GaSb platform. Passive components were designed to operate, in particular, at around 2.6 µ m for monolithic integration with active photonic devices on the III–V gallium antimonide material platform. The three popular types of splitters/combiners such as directional couplers, multimode interferometer-, and Y-branch-couplers were theoretically investigated. Based on our optimized design and rigorous analysis, fabrication-compatible 1 × 2 optical power splitters with less than 0.12 dB excess losses, large spectral bandwidth, and a 50:50 splitting ratio are achieved. For fiber-to-chip coupling, we also report the design of GCs with an outcoupling efficiency of ∼29% at 2.56 μ m and a 3 dB bandwidth of 80 nm. The results represent a significant step towards developing a complete functional photonic integrated circuits at mid-wave infrared wavelengths. 

A fully-functional photonic integrated circuit (PIC) platform with supporting active and passive components in the extended short- and mid-wave infrared spectral regime is of significant research interest for next-generation optical systems. Here we design offset quantum well-based photonic integrated circuits which primarily consist of four section-based widely tunable single-mode lasers emitting at 2560 nm. The platform requires the selective removal of InGaAsSb multi-quantum wells located above a GaSb-based optical waveguide layer and then subsequent single blanket GaSb regrowth. Encouraging preliminary experimental results on regrowth are also reported to confirm the feasibility of the proposed PICs. The simulation result for the tunable laser design shows that a tuning range as wide as ~120 nm is possible. The quasi-theoretical work performed here is an initial step towards demonstrating complex non-telecommunication PICs which could offer a comprehensive range of photonic functionalities.