[OPTICAL REVIEW Vol. 10, No. 4 (2003) 185-195]
© 2003 The Optical Society of Japan

Dependence of the Signal-to-Noise Ratio for a Mixture of Coherent and Incoherent Sources on the Incoherent Source Spectral Profile

Gyeong-il KWEON* and Jung-ho CHOI1

Department of Optoelectronics, Honam University, 59-1 Seobong-dong, Gwangsan-gu, Gwangju 506-714, Korea
1Optical Amplifier Laboratory, LG Cable, Ltd., 1026-6 Hogye-dong, Dongan-gu, Anyang, Kyungki-do 431-080, Korea

(Received October 28, 2002; Accepted March 28, 2003)

A semi-classical theory of photodetection noise for an optically amplified signal has been obtained and the explicit dependence of the photovoltage variance on the incoherent source spectral profile has been identified. The theoretical predictions have been compared with experimental results measured using a digital sampling oscilloscope for cases of a coherent source, an incoherent source, and a mixture of coherent and incoherent sources.

Key words: Signal-to-noise ratio, SNR, optical amplifier, digital sampling oscilloscope, beat noise, photocurrent

*E-mail address: kweon@honam.ac.kr