Raman scattering

Raman scattering, named after physicist Chandrasekhara Venkata Raman (1888 - 1970), is a backscattering phenomenon that occurs in optical transmission media.

Raman scattering is a quantum physical effect based on the reflection of photons from the grating structures of the optical waveguide, where the wavelength of the reflected light changes slightly from the incident light.

The Raman effect can be detected and evaluated with spatial accuracy using optical time domain reflectometry ( OTDR). An alternative method is Optical Frequency Domain Reflectometry( OFDR), which measures the frequency change ofa modulation signal.