High-Precision Apparatus for Measurement of the Cut-Off Wavelength of Single-Mode Optical Fiber

Problems that arise in the course of attempting to determine and monitor an optical fiber, the medium of transmission of fiber-optic communication systems, are considered. One of the controllable parameters is the cut-off wavelength of a single-mode optical fiber. The cut-off wavelength defines the minimal wavelength of optical radiation at which an optical fiber supports only a single propagated mode, i.e., it functions in a single-mode regime. The problem of determining the cut-off wavelength of an optical fiber used in fiber-optic communication systems is critical, since in a multi-mode regime of operation of an optical fiber its throughput decreases as a consequence of inter-mode dispersion. Methods of measuring the cut-off wavelength of an optical fiber are considered. A model of a new high-precision apparatus for measurement of the cut-off wavelength of an optical fiber is proposed. The measurements are performed on the basis of the reference bending method described in GOST R MEK 60793-1-44-2013. The precision characteristics of the newly developed apparatus are analyzed and a quantitative assessment of the measurement error is obtained.