Patent ID: 11519817

Abstract:
An object of the present invention is to provide a Raman gain efficiency distribution testing method and a Raman gain efficiency distribution testing apparatus for measuring a Raman gain efficiency distribution of a fundamental mode and a first high-order mode in a few-mode fiber. The Raman gain efficiency distribution testing method and the Raman gain efficiency distribution testing apparatus according to the present invention compute a Raman gain coefficient of a tested optical fiber from a Raman gain coefficient of a pure quartz core optical fiber at an excitation wavelength of 1 μm, a wavelength of excitation light, and a relative refractive index difference between a core and a clad at an arbitrary position z, compute electric field distribution overlap integrals at an arbitrary position z, between modes, of a mode field diameter of each mode at a wavelength of signal light, and a mode field diameter of each mode at a wavelength of excitation light; and compute the product of the Raman gain coefficient and the electric field distribution overlap integrals, and acquire Raman gain efficiencies, between modes, of the signal light and the excitation light at the arbitrary position z.