Electrical Modelling of High-speed Photodiodes
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Wireless, photonics and space engineering (MPWPS), MSc
Publicerad
2024
Författare
Muppathiyil, Geo Philip
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Photodiodes are pivotal components in optoelectronic systems, converting light into
electrical signals with applications spanning from telecommunications to medical
devices. This thesis presents a comprehensive study on the electrical modeling
of photodiodes, aiming to enhance their performance when integrated with transimpedance amplifiers (TIAs) in receivers.
The research commences with an in-depth analysis of the physical principles governing photodiode operation. Various modeling techniques are examined, with a
particular emphasis on equivalent circuit models that accurately represent the photodiode’s behavior under different biasing conditions.
The model is constructed based on experimentally measured frequency response and
single-port reflection of the device. Devices with varying optical apertures and different biasing pads are analyzed. It is observed that the ground-signal pad geometry
introduces additional inductance to the electrical model, enhancing the frequency
response by up to 5 GHz compared to the ground-signal-ground pads. The study
also compares the performance of several photodiode prototypes, varying parameters such as absorber thickness and extraction layer thickness. Furthermore, the
combined response of the photodiode and TIA was simulated. The results indicate
that the frequency response, when combined with the TIA for ground-signal pad
geometry, remains flat up to 35 GHz, outperforming the ground-signal-ground design. This ensures that the receiver is free from frequency-dependent distortions.
The responsivity and dark current characteristics of the devices are also measured.
In conclusion, the electrical modeling techniques presented in this thesis offer a
powerful framework for understanding the photodiode performance with TIA in
optical recievers. The findings contribute to the advancement of optoelectronic
technology, paving the way for more efficient and versatile applications in various
fields such as data centers and other high-speed communication systems.
Beskrivning
Ämne/nyckelord
Photodiode, Frequency response, scattering parameters, Transimpedance amplifier, Absorber layer, Extraction layer, Ground-signal, Ground-signal-ground, Voltage-controlled current source