OPTICAL MEASUREMENT SYSTEM AND OPTICAL MEASUREMENT METHOD
The present disclosure is an optical measurement system for measuring Rayleigh scattered light and Brillouin scattered light in an optical fiber by injecting light into both ends of the optical fiber, wherein injected light for the Rayleigh scattering includes frequency multiplexing pulses, and one pulse of the frequency multiplexing pulses is used as pump light for the Brillouin scattering.
1 . An optical measurement system for measuring Rayleigh scattered light and Brillouin scattered light in an optical fiber by injecting light into both ends of the optical fiber,
wherein injected light for the Rayleigh scattering includes frequency multiplexing pulses having a predetermined frequency interval, and
one pulse of the frequency multiplexing pulses is used as pump light for the Brillouin scattering.
2 . The optical measurement system according to claim 1 , wherein local light is generated by splitting continuous light, and
phase detection of the Rayleigh scattered light generated in the optical fiber is performed using the local light.
3 . The optical measurement system according to claim 1 , wherein frequency sweep of probe light is performed within a range in which a Brillouin gain spectrum from the pump light is extractable.
4 . The optical measurement system according to claim 1 , wherein the predetermined frequency interval has a frequency interval wider than a spread of a Brillouin gain spectrum due to a time width of each pulse included in the frequency multiplexing pulses.
5 . The optical measurement system according to claim 4 , wherein the predetermined frequency interval is determined using convolution of a pulse spectrum of the frequency multiplexing pulses and a gain spectrum with assumption that the pump light is a continuous wave at a single frequency.
6 . The optical measurement system according to claim 1 , wherein a frequency band of a reception unit of Rayleigh scattered light is narrower than a frequency band of an entire pulse spectrum of the frequency multiplexing pulses.
7 . The optical measurement system according to claim 1 , wherein the Rayleigh scattered light and the Brillouin scattered light generated in the optical fiber are separated using a fiber Bragg grating (FBG).
8 . An optical measurement method of measuring Rayleigh scattered light and Brillouin scattered light in an optical fiber by injecting light into both ends of the optical fiber,
wherein injected light for the Rayleigh scattering includes frequency multiplexing pulses, and
one pulse of the frequency multiplexing pulses is used as pump light for the Brillouin scattering.