Frequency-Converting Photonic Link With BSSA Amplification

A photonic system has been devised for acquiring a radio-frequency (RF) signal from a remote receiving antenna via a long optical fiber. The system performs multiple functions, including upward or downward frequency conversion, optical amplification [more specifically, Brillouin selective sideband amplification (BSSA)] in the long optical fiber, and other functions, the combined effects of which are to eliminate sensitivity to polarization and to minimize signal fading caused by dispersion in the long optical fiber. The basic design of the system also makes it possible to use phase modulators. In comparison with amplitude modulators, phase modulators exhibit lower losses and cost less; moreover, unlike amplitude modulators, phase modulators do not require bias and thus do not present any bias-stabilization problems in design and operation.