Postprocessing Phase Stabilizer for Wide Frequency Range Photonic-Microwave Signal Distribution

In the field of leading-edge techniques, such as broadband communications and large-scale radio interferometer applications, the need for a highly stable/wide-frequency-range photonic-microwave signal (continuous sine wave) is increasing. The main purpose of this research is to provide a highly stable photonic-microwave signal over a large broadband from microwave to terahertz frequencies using the same optical signal generation/transmission system. While transmitting signals through an optical cable, the transmission delay fluctuates and it suffers from chromatic dispersion that affects the distribution signal coherence. We have developed a postprocessing scheme transmission phase stabilizer. In the scheme, the measured phase of the round-tripped signal is acquired at time intervals at the optical transmitting port (an optical input port), and then the measured phase data are sent to the destination port (an optical output port) for the transmission phase compensation. The postprocessing method has advantages for a frequency dynamic range and compensation range issue. Theoretically, there is no upper frequency limit on the proposed phase stabilizer. We also discuss a high-frequency signal generator based on an optical comb signal generator up to terahertz frequencies.