Development of a Novel Approach for Accurate Measurement of Noise in Laser Diodes used as Transmitters for Broadband Communication Networks: Relative Intensity Noise

This paper is focused on the Relative Intensity Noise (RIN) aspect of a research project on development of a novel approach for accurate measurement of RIN and Frequency Excursion (Chirp) in Laser Diodes as Transmitters for Optical Communication Networks. The desired metrology capabilities have been developed and demonstrated, providing significantly improved sensitivity and accuracy than existing methods. RIN is a key parameter for laser components used in telecommunication systems due to the drive to reduce inherent noise, improve overall signal-to-noise ratio and thus increasing achievable communication link length and reduce required component specification. The novelty of our approach has resulted significant advantages, achieving improved sensitivity, improving measurement accuracy as low as ±1dB and simplifying the system calibration methodology thus improving flexibility. Laser RIN’s of between 10 to 14dB below the Shot RIN have been shown (typically -170dB/Hz) which is a direct result of the improved system sensitivity.