Time-Expanded Φ-OTDR Based on Binary Sequences

In this letter, the capabilities of time-expanded phase-sensitive optical time-domain reflectometry (TE Phi-OTDR) using binary sequences are demonstrated. We present a highly flexible and integrable TE Phi-OTDR approach that allows a customized distributed optical fiber sensor (range, spatial resolution, and acoustic sampling) by simply changing the length of the binary sequence and the reference clock frequencies of the binary sequence generators. The here presented architecture eliminates the need for the cumbersome arbitrary signal generators used to date to create the dual-comb spectra for interrogating the fiber. In this approach, the use of large binary sequences allows us to obtain dual combs in a simple and cost-effective way. Spatial resolution of similar to 1 cm is achieved, attaining similar to 15,000 independent measurements points along the interrogated fiber, with a capability of sensing similar to 30,000 measurements points.

Automated summary

This letter demonstrates the capabilities of time-expanded phase-sensitive optical time-domain reflectometry (TE Phi-OTDR) using binary sequences. The presented approach allows for a customized distributed optical fiber sensor by changing the length of the binary sequence and the reference clock frequencies. The use of large binary sequences eliminates the need for arbitrary signal generators and enables simple and cost-effective creation of dual comb spectra.