In some OFDR implementations it is advantageous to use sinusoidal frequency tuning and to work in the linear range of the sinusoid. For a given scan frequency this limits the maximum length of the interrogated fiber. We propose a new method which allows exceedingly large delays while maintaining high scan rates. It is based on the observation that delay of half the scan period yields linearly frequency modulated (LFM) signals at the OFDR receiver. Using Fractional Fourier Transform (FrFT) for processing the raw data enables measurement of the z-dependent reflection at long ranges with high resolution and high scan rates.

Date Published: 2 June 2014
PDF: 4 pages
Proc. SPIE 9157, 23rd International Conference on Optical Fibre Sensors, 91576T (2 June 2014); doi: 10.1117/12.2059621

Published in SPIE Proceedings Vol. 9157:
23rd International Conference on Optical Fibre Sensors
José M. López-Higuera; Julian D. C. Jones; Manuel López-Amo; José Luis Santos, Editor(s)