This paper discusses a new approach to coherently channelizing input rf signals that is similar to Bragg cell techniques but has the potential for operation at substantially higher bandwidths. The rf information from the environment is modulated on a laser beam. The modulated laser beam is then demultiplexed according to frequency by passing the beam through a dispersive device. The various channels are then each incident on the respective element of a detector array. Splitting a reference beam off from the main beam provides a local oscillator for heterodyne detection at the detector array. The optically encoded rf information is thereby translated back down to baseband or a common if band.
E. M. Alexander,
A. E. Spezio,
"New Method Of Coherent Frequency Channelization", Proc. SPIE 0388, Advances in Optical Information Processing I, (23 December 1983); doi: 10.1117/12.935011; https://doi.org/10.1117/12.935011