Involvement of free-space optics in Raman distributed temperature sensing

Area of Science:

• Optics and Photonics
• Sensing Technologies
• Fiber Optics

Background:

• Distributed temperature sensing (DTS) traditionally relies on fiber optic cables.
• Installation and repair of DTS cables face significant challenges due to cost and topographical constraints.
• A need exists for alternative, flexible transmission methods for DTS.

Purpose of the Study:

• To demonstrate the efficacy of free-space optics (FSO) as a transition channel for transmitting Raman backscattering signals in DTS.
• To evaluate the performance of an FSO link within a Raman-based DTS (RDTS) system.
• To explore FSO's potential to overcome limitations of traditional DTS cable installations.

Main Methods:

• Integration of a free-space optics (FSO) link as a barrier-free air segment within a Raman-based DTS (RDTS) transmission route.
• Transmission of RDTS pulses through the FSO link for low-loss propagation.
• Collection and interpretation of Raman backscattered signals after traversing the FSO link.

Main Results:

• Successful transmission of Raman backscattering signals through the FSO air segment.
• Minimal signal loss and temperature measurement accuracy maintained across the FSO link.
• Temperature readings before and after the FSO link showed negligible differences.

Conclusions:

• Free-space optics (FSO) provide a viable and effective air transition channel for Raman-based distributed temperature sensing (RDTS).
• This FSO-RDTS approach offers a promising solution to reduce the high costs and installation difficulties associated with conventional DTS fiber optic cables.
• The technology addresses challenges posed by complex terrains, paving the way for more accessible and economical temperature monitoring solutions.