Stable radio-frequency delivery by λ dispersion-induced optical tunable delay

We propose and demonstrate a novel stable radio frequency (RF) delivery system based on a radio-over-fiber link. The proposed scheme acts as a long phase-locking loop where an optical tunable delay line is involved to compensate dynamically for the time-delay variation that arises from fiber-link fluctuation. An optical carrier with variable wavelength under fiber-link dispersion results in the desired tunable delay. The tunable range is in proportion to the length of the fiber link, so a large phase-error correction capacity under long-distance delivery can be realized. The large as well as fine optical-delay tunability is experimentally demonstrated, and the RF reference of 2.42 GHz is transferred for 54 km where a time jitter compression factor of 588 is achieved.