METHOD DETERMINING COEFFICIENT OF BACKWARD SCATTERING OF OPTICAL FIBER AND DEVICE FOR ITS REALIZATION Russian patent published in 2001 - IPC

FIELD: optics. SUBSTANCE: method determining coefficient of backward scattering of optical fiber includes connection of first output of optical directional coupler to input of tested optical fiber, feed of sounding optical pulses to input of directional coupler, measurement of level of power of backward scattering in nearest end across second output of directional coupler, connection of output of tested optical fiber to input of reference optical fiber whose coefficient of backward scattering is known, measurement of characteristic of backward scattering across second output of optical directional coupler which is used to evaluate losses a_t, in connection of tested optical fiber with reference one on side of tested fiber, subsequent connection of first output of optical directional coupler to input of reference optical fiber and determination of losses a_r in connection of tested optical fiber to reference one on side of reference optical fiber in same manner. Coefficient of backward scattering of tested optical fiber in decibels is found by formula K=K₀ = 0,5(a_t-a_r), where K₀ is coefficient of backward scattering of reference optical fiber, dB with length of tested and reference optical fibers more than five times as much as value ΔL = Δt·n/c, where Δt is duration of sounding pulses; n is group refractive index of core of tested optical fiber; c is velocity of light in free space. Device for realization of proposed method has optical directional coupler 2, generator 1 of optical sounding pulses, photoconverter 4, display 5, optical switch 3, gating unit 7 and control unit 6. EFFECT: expanded field of application of invention. 2 cl, 1 dwg