Raman amplification /ˈrɑːmən/ is a way of increasing the signal strength in an optical fiber. It is often used in a fiber that carries a signal for a long distance (such as in an undersea cable). Technically, it works by stimulating Raman scattering, in which a lower frequency 'signal' photon induces inelastic scattering of a higher-frequency 'pump' photon in an optical medium in the nonlinear regi. Further reading• Poem, Eilon; Golenchenko, Artem; Davidson, Omri; Arenfrid, Or; Finkelstein, Ran; Firstenberg, Ofer (26 October 2020). • •.