M.Sc Thesis

M.Sc StudentBloch Eli
SubjectAn InP Based Broadband Differential Transimpedance Amplifier
for 40Gbs DPSK Photoreceivers
DepartmentDepartment of Electrical and Computer Engineering
Supervisor PROF. Dan Ritter
Full Thesis textFull thesis text - English Version


The growing data volume of optical networks demands faster transmitters and receivers for higher data-rates. Today’s Photoreceivers front-end consists of a photodiode (PD) and a transimpedance amplifier (TIA) as discrete components. Their connection is a major concern for ever increasing data-rates. The induim phosphide/indium gallium arsenide (InP/InGaAs) material system is used for high speed electronics due to high electron velocity. Today’s double heterojunction bipolar transistors (DHBT) exhibit cutoff frequencies of 300GHz and higher. In addition, the 0.75eV direct bandgap of InGaAs suitable for the detection of light of a wavelength of 1.5μm used in optical communication systems. This makes InP/InGaAs ideal for monolithic PD? integration.

This research focuses on design of an InP broadband TIA for 40Gbs DPSK optical communication that exhibits large signal limiting capabilities as well as small signal high gain. The TIA can be monolithically integrated with a PD pair in future work. The work presented here covers all the stages of integrated circuits manufacturing, starting with a single device design considerations and its modeling, continuing with TIA schematics and layout design and concluding with electrical characterization.

Two TIA configurations were manufactured and evaluated. A full TIA which exhibits bandwidth of 10GHz and a transimpedance gain of 1000Ω and a simplified version with 20GHz bandwidth and 250Ω gain.