Study of group III-V waveguides on sapphire platform for photonic integrated circuits

Photonic integrated circuits (PICs) are widely recognized as promising platforms for a range of applications, including data communication, LiDAR for autonomous vehicles, and advanced sensing technologies. While individual optical components have been successfully demonstrated, the integration of both electronic and photonic elements on a single platform has become a key technology enabler—enhancing the stability, scalability, and overall performance of PIC systems. Recently, we proposed the use of sapphire as a high-performance PIC platform. This approach enables a fully integrated solution that includes a complete suite of components—light sources, modulators, photodetectors, passive devices, and silicon-on-sapphire control circuits—on a single sapphire substrate, offering a pathway toward high-performance, low-cost mixed-signal optical links. In parallel with our development of active components, such as group III-V lasers on sapphire, this work systematically investigates the performance of group III-V straight waveguides on sapphire. The refractive index contrast between GaAs, InP, GaSb, and sapphire is sufficiently high to support low loss waveguiding across a broad optical wavelength range. The simulated propagation losses at wavelengths of 1330nm, 1550nm, and 2000nm are 0.32dB/cm for GaAs, 0.67dB/cm for InP, and 0.70dB/cm for GaSb rib waveguides, respectively. Since straight waveguides serve as the fundamental building blocks for all passive components, the results presented here provide a foundation for assessing and designing additional passive photonic structures on the sapphire platform.