Noise spectra in balanced optical detectors based on transimpedance amplifiers

Area of Science:

• Electrical Engineering
• Optical Physics
• Signal Processing

Background:

• Balanced optical detectors are crucial for various applications.
• Understanding noise sources is vital for optimizing detector performance.
• Operational amplifiers in transimpedance configurations are common in optical detector circuits.

Purpose of the Study:

• To theoretically analyze and experimentally investigate shot and electronic noise spectra in a balanced optical detector.
• To identify and quantify parameters limiting circuit performance, specifically bandwidth and noise clearance.
• To compare experimental findings with theoretical predictions.

Main Methods:

• Theoretical modeling of noise spectra for a transimpedance operational amplifier circuit.
• Experimental measurements of shot and electronic noise spectra.
• Analysis of noise characteristics, including frequency dependence and filter response.
• Comparison of experimental data with theoretical models and manufacturer specifications.

Main Results:

• Shot noise spectrum is consistent with a second-order Butterworth filter response.
• Electronic noise exhibits a linear increase with the square of the frequency.
• Good agreement observed between theoretical predictions and experimental results.
• Measured capacitances of operational amplifier inputs and photodiodes exceeded datasheet values.

Conclusions:

• The study provides a comprehensive understanding of noise limitations in balanced optical detectors.
• Discrepancies in component capacitance highlight the importance of independent verification.
• The findings are valuable for designing and improving high-performance optical detection systems.