Hybrid Raman/Brillouin-optical-time-domain-analysis-distributed optical fiber sensors based on cyclic pulse coding.

We experimentally demonstrate the use of cyclic pulse coding for distributed strain and temperature measurements in hybrid Raman/Brillouin optical time-domain analysis (BOTDA) optical fiber sensors. The highly integrated proposed solution effectively addresses the strain/temperature cross-sensitivity issue affecting standard BOTDA sensors, allowing for simultaneous meter-scale strain and temperature measurements over 10 km of standard single mode fiber using a single narrowband laser source only.

Cyclic pulse coding for fast BOTDA fiber sensors.

A cyclic pulse coding technique is proposed and experimentally demonstrated for fast implementation of long-range Brillouin optical time-domain analysis (BOTDA). The proposed technique allows for accurate temperature and strain measurements with meter-scale spatial resolution over kilometers of standard single-mode fiber, with subsecond measurement times.

High-performance hybrid Raman/fiber Bragg grating fiber-optic sensor based on simplex cyclic pulse coding.

We propose and experimentally demonstrate the use of cyclic pulse coding to improve the performance of hybrid Raman/fiber Bragg grating (FBG) fiber-optic sensors, for simultaneous measurement of distributed static temperature and discrete dynamic strain over the same sensing fiber. Effective noise reduction is achieved in both Raman optical time-domain reflectometry and dynamic interrogation of time-division-multiplexed fiber FBG sensors, enhancing the sensing range resolution and providing real-time point dynamic strain measurement capabilities. The highly integrated sensor scheme employs broadband apodized low-reflectivity FBGs, a single narrowband optical source, and a shared receiver block.