Cancellation of Vibration-Induced Phase Noise in Optical Fibers

Vibration causes mechanical distortions in optical fibers that induce phase fluctuations in the transmitted optical signal. Information encoded on the optical signal by modulation, such as in a radio-frequency (RF)-photonic link also degrades. A feed-forward correction technique is described that enables 20 dB or more cancellation of vibration-induced phase fluctuations in an optical fiber wound on a spool. The scheme is also applied to an optoelectronic oscillator (OEO). The OEO has emerged as an excellent low-noise source that rivals the best electronic RF oscillators over a broad range of offset frequencies. However, close-to-carrier spectral purity of an OEO is degraded mostly by the vibration-induced phase fluctuations in optical fibers when the temperature is held constant. Implementation of feed-forward phase correction in an OEO has shown improvement by almost an order of magnitude in the vibration sensitivity of the oscillator.