Variation of Relative Intensity Noise With Optical Power in InGaAsP Semiconductor Optical Amplifier

Relative intensity noise (RIN) is an index to evaluate the amount of noise compared to the optical intensity, which is widely believed to be increased by optical amplification. A previous paper, however, pointed out that theoretically the RIN of the output light of a semiconductor optical amplifier can be reduced from that of the input light, and that the RIN level is determined by the output optical power almost independently from the RIN level of the input light. Detailed experimental data to support these postulations are given in this letter.