Laser Amplifier Detector for Broadband Network Control

In subcarrier multiplexed (SCM) or other broadband networks, a simple and low-cost network surveillance and control channel is desirable. It has been demonstrated that inline laser amplifiers (LA) can significantly improve the power budget of broadband networks including the point-to-multipoint SCM distribution system [1]. It is also well understood that LA's can be used to amplify and detect signals at the same time [2]. A number of applications have been reported, including laser characterization, frequency control, amplifier gain control, etc. [3-5]. In this paper we report for the first time the feasibility study of using a travelling-wave laser amplifier (TWLA) as an inline optical amplifier for multiple broadband FSK channels and simultaneously as a control channel detector/amplifier in an SCM system. Bit-error-rate and carrier-to-noise performances for both the control channel and the FSK channels are presented.