Terahertz Bandwidth Optical Comb Generation Using Optoelectronic Phase-Locked Loop

This paper proposes a THz bandwidth optical comb generation scheme by phase modulating two optical carriers simultaneously in an electrooptic overdriven phase modulator. The frequency difference between the two optical carriers is maintained constant by using an optoelectronic phase locked loop (OEPLL). It has been shown analytically that taking a microwave drive frequency of 25 GHz, 41 comb lines, lying within a power envelope of 20 dB, span over a frequency bandwidth of 1 THz with a comb line spacing of 25 GHz.