Abstract
Raman amplification in a fiber transmission line is described in terms of quantum mechanics. The evolution of the light field operator is derived on the basis of the Heisenberg equation, including Raman interaction and a beam-splitter model that simulates the fiber propagation loss. The light field operator thus derived is then used to evaluate physical quantities, such as mean amplitude, mean photon number, and their variances. The results obtained are equivalent to conventional classical expressions, providing a logical quantum mechanical base for the conventional phenomenological treatment. In addition, the effect of the propagation loss on quantum noise is clarified, which is not taken into account in the classical treatment.
© 2018 Optical Society of America
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