The transmission characteristics of a Raman-amplified atomic filter that can be used to detect fairly weak signals in free-space quantum-key distribution or laser communications are analyzed and discussed in the coherent and incoherent pump fields respectively. The theoretical model for the calculation of the transmission characteristics of a ground-state Raman-amplified Faraday dispersion atomic optical filter based on Raman gain and Faraday rotation is presented. The results show that the filter in a coherent pump field can achieve higher transmission and larger tunability than that in an incoherent pump field due to elimination of pumping detuning. In addition, the filter has a large scale tunability over 3.5 GHz via the Faraday transmission peak adjusted while its bandwidth is only 66 MHz, which is useful for free-space laser communication and lidar systems.
© 2014 Optical Society of AmericaPDF Article