TECHNIQUE FOR STABILIZING THE PHASE OF THE REFERENCE SIGNALS IN ANALOG FIBEROPTIC LINKS

The effects of temperature and longitudinal stress on the phase delay of reference signals in a fiber-optic link are discussed. A feedback s ystem that uses a fiber-optic phase modulator is used to compensate fo r the phase fluctuations of a reference signal in the link. The phase deviations of a 50-MHz reference frequency that are caused by temperat ure variations of the link is reduced by more than 95% on optimization of the correction system. The advantages of this technique are that t he fiber-optic phase modulator has a greater stability compared with t he electronic phase modulators, and signal conversions from electric t o optic and optic to electric are avoided. (C) 1995 Optical Society of America