Pulse-compression optical time domain reflectometer

This paper introduces a novel pulse-compression optical time domain reflectometer (OTDR) by utilizing linear frequency modulation (LFM) pulse-compression technology. The working principle of the pulse-compression OTDR is demonstrated. The spatial resolution is determined by the sweeping range of the pulsed LFM instead of the pulse width, which solves the dilemma of spatial resolution and measurement range in the conventional OTDR. A preliminary experiment of the pulse-compression OTDR is performed, providing 55 cm spatial resolution and 5.4 km measurement range under 2 μs pulse, 221 MHz LFM sweeping range, and 100 kHz linewidth laser diode. It is expectable to achieve a spatial resolution of less than 1 cm and dozens-kilometer measurement range by tens of GHz LFM sweeping ranges via microwave photonics.