Active detection of propagation delay variations in single way time transfer utilizing dual wavelengths in an optical fiber network
Paper i proceeding, 2011
Several communication systems of today rely on the real time accessibility of accurate time and frequency measures and there is an increasing demand for the development of new and redundant methods for the distribution of these measures. The classical two-way method is able to compensate for the inevitable variations in the time and frequency propagation delay. The two-way method is used for time transfer in free space, electrical or optical domain, but has the disadvantage of often using two different paths for transmitting back and forward. The paths may be of equal length and have equal propagation delay, but nevertheless there is often a remaining asymmetry in the propagation paths. The inevitable asymmetry between the paths in the time transfer delay must be detected and compensated for, if an accuracy better than s-level is needed for transmission distance exceeding a few km. Furthermore, if the number of users is high, there will be a complex and large network of two-way time signal transmissions. Therefore, a solution using one-way broadcasting would be more desirable, and would be possible if the variations in transmission time could be estimated from the received data at the far (user) end. The one-way method uses only one path of transmission and is possible to implement in existing Wavelength Division Multiplexing-networks. Proof of concept and results of this one-way time transfer technique based on transmission of a repetitive signal, modulated on two lasers at different wavelengths 8 nm apart and transmitted through an optical fiber, has been presented previously. These data showed a strong correlation between a change in transfer time at one wavelength, and the transfer time difference for the signals at the two wavelengths. In this paper, the setup and the measurement results have been improved and new data is collected which shows improvement in the reliability and quality of this technique. The stability is improved through component analysis and minimizing error sources. The distance is improved from 38km to 160km.
Wavelength division
Transmission distances
Propagation delays
Component analysis
Frequency measures
Real time
Error sources
Two wavelength
Measurement results
Transmission time
Strong correlation
Optical domains
Transfer time
Large networks
Optical fiber networks
Free space
Optical communication
Multiplexing equipment
Communication systems
Time transfer techniques
Proof of concept
Time transfer
Dual wavelength
Time signals
Propagation paths
Optical fibers
Multiplexing
Real time systems
Active detection
Fiber optic networks
Författare
Sven-Christian Ebenhag
Chalmers, Mikroteknologi och nanovetenskap, Fotonik
Per Olof E Hedekvist
Chalmers, Mikroteknologi och nanovetenskap, Fotonik
R. T. Kenneth Jaldehag
SP Sveriges Tekniska Forskningsinstitut AB
Proceedings of the IEEE International Frequency Control Symposium and Exposition
5977328
978-1-61284-111-3 (ISBN)
Ämneskategorier
Elektroteknik och elektronik
DOI
10.1109/FCS.2011.5977328
ISBN
978-1-61284-111-3