V-groove all-fiber intermodal Mach-Zehnder interferometer and its high-temperature sensing application

Laser pulse width is the limiting factor for high spatial resolution measurement with Raman distributed temperature sensor (RDTS). Typically a 10 ns laser pulse provides a spatial resolution of 1 m. Path delay multiplexing can be used to overcome this limitation. This paper presents formalism for two path delay multiplexing, taking into account the point response function (PRF) of the RDTS.