Research and development of 40 GHz bandwidth laser relative intensity noise measurement system using PID controller and ESA spectrum analyser

Measuring and evaluating the quality of laser sources used in optical communications precision measurement system is essential. Relative intensity noise (RIN) a parameter that directly affects quality. Therefore, RIN needs to be measured periodically. This study presents high-sensitivity, broadband (40 GHz) using precisely temperature-controlled photodetector an electrical spectrum signal analyser. value determined through indirect components: thermal noise, total detected shot source. These noises are by Electrical analyser (ESA) super sensitive 61/2 digital multimeter (DMM). The experimental results reference Distributed feedback (DFB) source show similarity between provided manufacturer.