PURPOSE: To measure the local optical losses of optical fibers and the connection losses of connected optical fibers over a wide wavelength range by utilizing the nonlinear optical effect of Raman scattering, 4-photon mixing, etc. that arise when strong light is propagated in an optical fiber.
CONSTITUTION: The length that generates wavelength conversion is shorter as the core area A of an optical fiber is smaller and the power P0 and Raman gain constant gs of pumping light are larger. This invention makes it possible to measure the dependency of the local light losses and connection losses of an optical fiber upon wavelength by utilizing the above-mentioned property. In the case of a single mode optical fiber as an optical fiber 3 to be measured, its core diameter is as extremely small as about 10μm and has low losses; therefore light density is high and the length that provides a mutual effect is long. Therefore 4-photon mixing arises other than Raman scattering, and the spectra after wavelength conversion are flat with respect to the wavelength. In the case of a multimode optical fiber, many crests are generated in its spectra; therefore the loss characteristics at specific wavelengths are obtained.
NAKAZAWA MASATAKA
HORIGUCHI TSUNEO
UCHIDA NAOYA
