Phase noise characteristics of all-optical single sideband frequency upconverter for radio-over-fibre applications

The phase noise characteristics of an all-optical single sideband frequency upconverter that uses an optical interleaver and a semiconductor optical amplifier are experimentally investigated. While the phase noise characteristic of the upconverter is limited by that of the LO signal source, it becomes degraded owing to the path imbalance of the two optical signal paths. Compensation for the path imbalance by a delay line produces an optimised phase noise of the upconverted RF signal of approximately -98 dBc/Hz at the offset frequency of 10 kHz.