May 15 2014
The Gordon-Haus jitter is a timing jitter that originates from the fluctuations in center frequency. This jitter has been greatly influencing long-haul fiber soliton systems by causing a jitter in the output of fiber links.
There are several mechanisms that cause timing jitter in communication systems, either during pulse generation in lasers, or propagation in optical fibers. A jitter is undesirable, as it generates noise in communication.
Basic Principle
The Gordon-Haus effect is due to the combination of fluctuations in the center frequency of optical pulses with the timing. Therefore, a change in the center frequency causes a change in group velocity, which in turn affects the pulse timing.
Gordon and Haus considered the noise in a fiber-optic link in periodically spaced fiber amplifiers. In these amplifiers, it is assumed that they have a wavelength-independent gain that introduces a quantum noise. This noise randomly causes a shift in the optical center frequency.
With more and more shift in the center, the timing deviations of pulses accumulate. The cumulative effect of these deviations causes growing timing errors.
The Gordon-Haus analysis was based on soliton pulse propagation for long-haul data transmission. This jitter can be suppressed considerably by using regularly spaced optical filters, or amplifiers having a limited gain bandwidth. In case of mode locked lasers there is an effect of timing drift, due to the Gordon-Haus jitter.
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