Efficient compact modelling of UTC-photodiode towards terahertz communication system design

Monolithic optoelectronic integrated circuits, OEICs are seen as key enabling technologies to minimal power loss criteria. Monolithic OEICs combine, on the same die, cutting-edge optical devices and high speed III-V electronics able to generate terahertz signal targeting beyond-5G networks. Computationally efficient compact models compatible with existing software tool and design flow are essential for timely and cost-effective OEIC achievement. The analog nature of photonic devices wholly justifies the use of methodologies alike the ones employed in electronic design automation, through implementation of accurate (and SPICE-compatible) compact models. This multidisciplinary work, describes an efficient compact model for Uni-Traveling Carrier photodiodes (UTC PD) which is a key component for OEICs. Its equations feature the UTC PD electronic transport and frequency response along with its photocurrent under applied optical power. It also dynamically takes into account the device junction temperature, accounting for the self-heating effect. Excellent agreement between model and measurements as well as model scalability (several geometries have been validated) has been achieved that marks the first demonstration of a multi-physics, computationally efficient and versatile compact model for UTC-PDs.