Photonic THz Generation using Optoelectronic Oscillator-driven Optical Frequency Comb Generator

Abstract

We propose and experimentally demonstrate a photonic THz signal generation technique combining a discrete optoelectronic oscillator (OEO) and optical frequency comb (OFC) generator. Using a microwave photonic filter (MPF), we generate an electrical oscillation up to 17.33 GHz with a phase noise of -103 dBc/Hz at 10 kHz offset frequency. The OEO frequency tunability is obtained by changing the bandwidth of a tunable optical band pass filter (TOBF). This can produce an electrical RF carrier from 6.58 GHz - 18.36 GHz. The OEO-driven optical comb generates 22 optical comb lines with a frequency spacing of 17.33 GHz covering a bandwidth of 360 GHz. By selecting two optical comb lines using a wavelength selective switch (WSS) and beating them in a uni-travelling carrier photodiode (UTC-PD), a THz wave is generated at 242.6 GHz with a phase noise of -78 dBc/Hz at 10 kHz offset frequency. This technique has potential for use in THz signal generation where it is possible to tune the THz carrier frequency by tuning the RF carrier generated from the OEO.