Advanced cyclic coding technique for long-range Raman DTS systems with meter-scale spatial resolution over standard SMF

A long-range fast-measurement Raman-based distributed temperature sensor (RDTS) with a meter spatial resolution exploiting a quasi-periodic pulse-coding technique is proposed in this paper. We experimentally demonstrate the feasibility of temperature sensing over 26 km standard single-mode fiber with 1 m spatial resolution obtaining 3°C of temperature resolution within 30 s of measurement time. Experimental results employing 1023-bits codewords are also reported, showing a notable range enhancement and enabling distributed sensing over 58 km distance with 2 m spatial resolution and 4°C of temperature resolution within 5 min measurement time.