Determination of the effective cut-off wavelength of several single-mode fiber patchcords

The effective cut-off wavelength is one of the important parameters in single-mode optical fiber. Nevertheless, the data sheet of an optical fiber patchcord generally does not specify the exact value of the cut-off wavelength. However, for certain applications, for example, to know the value of the numerical aperture, core radius and refractive index of the fiber at a certain wavelength, the exact value of the cut-off wavelength should be known. In this paper, we report the measurement of the cut-off wavelength of several commercially-available single-mode fiber patchcords, namely, the 780HP, SMF28, SM600, and SM2000. We used the multi-mode reference method in our measurement because it is simpler than the bend reference counterpart. From our measurements, the effective cut-off wavelengths for the above-mentioned fiber patchcords are (0.731 +/- 0.006) mu m, (1.225 +/- 0.005) mu m, (0.485 +/- 0.010) mu m, and (1.665 +/- 0.018) mu m, respectively, and its comparison with catalogue values has been discussed. The usefulness of the cut-off wavelength determination for calculating other fiber parameters has also been described.