Multi-function Optical Transceiver for Satellite Communications

Kurzfassung

This report presents an investigation into the performance of commercial on–off keying transceivers under both direct detection and coherent reception schemes, supported by the development of a Python-based simulation environment for photonic integrated circuits (PICs). Laboratory experiments were conducted to characterize the relationship between input optical power, signal strength, noise contributions, and signal-to-noise ratio (SNR) at the photodiode output. Direct-detection results showed an exponential dependence of SNR on input power, with transimpedance amplification improving sensitivity at low powers but saturating at higher powers. Having a transimpedance amplifier after the photodiode showed that the same SNR can be achieved at a lower input power, improving the receiver sensitivity. Coherent reception measurements demonstrated broadly comparable SNR values, with performance shaped by local oscillator noise and the nonlinear response of integrated variable optical attenuators and transimpedance amplifiers. These findings highlighted the critical importance of operating the receiver front-end within its optimal dynamic range. A modular simulation tool was developed in parallel to model PICs and system-level metrics such as power loss and SNR prior to fabrication, with preliminary simulations giving reasonable power loss and SNR values for a sample satellite feeder link scenario. Initial implementations focused on amplifier components and circuit handling functions, providing the basis for future extensions to modulators and advanced transceiver architectures. Together, the experimental and simulation results emphasize the trade-offs between direct-detection and coherent schemes, and demonstrate the value of accurate modeling for the design of multi-function PIC transceivers in high-throughput optical communication applications