A frequency shift keying transmitter based on incoherent frequency-to-time mapping for free-space optical communications

摘要

A novel frequency shift keying (FSK) transmitter for free-space optical communications based on incoherent frequency-to-time mapping is proposed and demonstrated. In the proposed system, an incoherent broadband optical source is spectrally shaped by an optical filter that has a sinusoidal frequency response and a tunable free spectral range (FSR), and then modulated at a temporal gate. The temporally gated optical signal is sent to a dispersive device to realize frequency-to-time mapping. By switching the FSR of the optical tunable filter that is controlled by a data sequence, a temporal sinusoidal signal with FSK modulation is thus generated after frequency-to-time mapping. The proposed transmitter is experimentally demonstrated. An FSK signal at a bit rate of 700 Mbits/s is experimentally generated.