Delta-Sigma Modulated Photodetection Method to Reduce Laser Power

The objective of the project is to examine a method for increasing the effectiveness of the photodetector by processing the small photodetector current rather than converting the signal to a relatively large voltage suitable for application to an analog-to-digital converter. The concept presents the potential to lower the laser power required, minimize data acquisition and data storage needs, and conduct "real-time" data interpretation.

This delta-sigma technique may be thought of as a form of analog-to-digital converter (ADC). The proposed network offers a means of processing electronic signals from transducers directly into a form of digital representation. By using integrated circuit methodologies, it is expected that very small signals can be measured more accurately than the more usual discrete-evel methods (ie: using discrete parts and printed circuit boards). In this particular study, these techniques are applied to photodetectors. By maintaining the quality of signals in the lower end of the dynamic range, a successful implementation will allow the use of smaller lasers (or further detection range for the same laser power) for a given application while implementing the receiving electronics in a much smaller and lower power package.