In 2021, scientists experimenting with fiber optics picked up a strange signal: the cacophony of cicadas. It could lead to a new way of monitoring insects.
I can’t really explain it any better than Wikipedia. You absolutely need a special transceiver, but it looks like the basic answer is that hot bits show up slightly differently to cold bits when doing TDR or similar measurements.
You send a light pulse down the cable, you get light bouncing back from each point in the cable. The time between sending the pulse and when you measure the received signal is how far away you’re measuring. Something about the received pulse - wavelength, power etc, allows you to estimate the temperature.
So, yeah. You build a fibre into your power cable, and plug one end into a box. It tells you the temperature of every meter of that fibre up to tens of kilometres, to within a degree.
https://en.m.wikipedia.org/wiki/Distributed_temperature_sensing
I can’t really explain it any better than Wikipedia. You absolutely need a special transceiver, but it looks like the basic answer is that hot bits show up slightly differently to cold bits when doing TDR or similar measurements.
You send a light pulse down the cable, you get light bouncing back from each point in the cable. The time between sending the pulse and when you measure the received signal is how far away you’re measuring. Something about the received pulse - wavelength, power etc, allows you to estimate the temperature.
So, yeah. You build a fibre into your power cable, and plug one end into a box. It tells you the temperature of every meter of that fibre up to tens of kilometres, to within a degree.