On the basis of the optical repeating and sensing technology

a novel ultra-long range optical fiber Raman temperature sensor solution is presented in this paper.The multistage optical repeating/amplifying/sensing devices are embedded among multiple sections of sensing optical cables of the sensor and the Raman scattering light from the fiber is intensified as the fiber loss is overcome by the gain of the devices.The cables are measured in sections and time.When the sensing cables are cascaded by introducing N such devices among multiple sections of the cables

N×L（L refers to the length of each piece of sensing fiber） ultra long-range monitoring of the sensor can be realized.The practical measurement results show that sensing signals with fairly high SNR can be obtained in a sensing and detecting range of 60 km.