A fiber based frequency distribution system with enchanced output phase stability
Paper in proceeding, 2009

Experimental results on the stability of the output phase of a frequency distribution system from several days of measurement is presented, in addition to a discussion regarding the influence of control loop parameters. The setup handles the issue that the output phase stability of a system depends on perturbations along the transmission length. This is especially critical if the signal is transmitted through optical fiber, at lengths of a few 100 m. An experimental evaluation using a laser based transmitter at a wavelength of 850 nm, and 625 m of multimode fiber where 575 m where placed outdoor, a temperature dependence of 100 ps/°C was detected. To compensate for these slow variations in real time, a setup using two-way transmission, in conjunction with an adjustable optical delay, was constructed. This device is adjusted to induce a delay variation of equal magnitude but opposite direction, in comparison to the delay change of the fiber. Calculating the modified Allan deviation of the transmitted signal, it is apparent that without active compensation, the deviation at τ below 1000 s is comparable to the values from the measurement system without transmission. At longer integration times, however, the slow variations in the fiber transmission will deteriorate the modified ADEV substantially. When activating the dynamic adjustment of pre-delay in the system, the deviation at shorter times will increase with a few dB, however, the modified ADEV decreases continuously with τ, eventually below the values for the uncompensated system. In conclusion, activating a dynamically controlled pre-delay in a fiber based frequency transmission system will induce a small penalty on fast variations of the output phase, however giving a remarkable improvement on slower variations. The usefulness of this added functionality must therefore be determined by the application of the signal.


Sven-Christian Ebenhag

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Per Olof E Hedekvist

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Carsten Rieck

Chalmers, Department of Radio and Space Science, Space Geodesy and Geodynamics

Håkan Skoogh

SP Sveriges Tekniska Forskningsinstitut AB

Per O. J. Jarlemark

SP Sveriges Tekniska Forskningsinstitut AB

R. T. Kenneth Jaldehag

SP Sveriges Tekniska Forskningsinstitut AB

Proceedings EFTF-IFCS2009 joint conference 20-24 April 2009, IEEE catalog number:CFP09FRE-CDR

1075-6787 (ISSN)

9781424435104 (ISBN)

Subject Categories

Control Engineering





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