The Maximum Operating Range of a Distributed Sensor Based on a Phase-Sensitive Optical Time-Domain Reflectometer Utilizing Telecommunication Fiber with Reflective Centers

An optimal arrangement of point reflectors inscribed by femtosecond laser pulses in a standard telecommunication fiber is found, which provides the maximum operating range of distributed sensors based on phase-sensitive optical time-domain reflectometers (φOTDRs). It is shown that the operating distance of an φOTDR utilizing probe pulses with a duration of 200 ns can be increased by 53 km using ultra-low-loss fiber with an attenuation of 0.16 dB/km, thereby extending it to 173 km without using distributed, remotely pumped, or in-line amplifiers. When using the most widespread standard telecom fiber with an attenuation of 0.185 dB/km, the operating distance can be increased by 48 km (up to 152 km total).