Real-time phase stable one-way frequency transfer over optical fiber

The fundamental and most straightforward method for high performance time and frequency transfer is the two-way technique, which is suitable when the user has access to the whole system, and when both transmission paths are equal or with a known and predictable asymmetry. Furthermore it is most practical when the numbers of users are limited and when no security concerns limit the bidirectional connectivity. An alternative technique for fiber based time and frequency transfer, utilizing a one-way co-propagation of two light waves, has been demonstrated previously. The technique utilizes dual wavelengths and measures the difference in group velocity to estimate the delay variation of the timing signal in one of the wavelength channels. This paper presents experimental data in a real-time delay compensated one-way frequency transfer and an investigation of the noise that is introduced in the receiver.