Use of laser diodes locked to atomic transitions in multiwavelength coherent communications

The possibility of building multiwavelength coherent communication systems based on low-cost semiconductor lasers in the 0.8µm range locked to rubidium linear absorption is investigated. The values of frequency offset between the resonances of both the D2 (780 nm) and D, (794.7 nm) lines are considered. A simple two-carrier FDM set-up using three resonances of the D2 line is presented and the optical frequency offsets are measured.