Abstract

There is great interest in developing low-noise optical amplifiers that can be used in optical communication systems. Optical amplifiers have been constructed from laser amplifiers, optical fibers, Raman cells, χ⁽²⁾ nonlinear crystals, and atomic vapors. Optical amplifiers that make use of two- beam coupling in atomic vapors are particularly important since they are able to amplify a continuous-wave multiple-transverse-mode optical signal with a single-pass gain greater than 10 at the bandwidths necessary for optical communications.¹ For these reasons, we present an experimental and theoretical study of the noise properties of a probe beam amplified through two-beam coupling in potassium vapor. We also describe the conditions under which this optical amplifier can operate as a quantum-noise-limited linear amplifier.

© 1993 Optical Society of America