Excess noise in a focused-gain amplifier
Philip R. Battle, J. G. Wessel, John L. Carlsten · Physical Review Letters · 1993
The gain-guided nature of an amplifier can lead to more noise in the output than would be predicted based on the quantum noise limit of 1 photon per mode. We report the results of an experiment which demonstrate that the gain-guided nature of a focused-gain Raman amplifier can lead to excess noise in the amplified field. The results are compared with a theoretical analysis of the output of an amplifier which incorporates the effects of gain guiding as well as the focused nature of the gain profile.