Mode field diameter and cut-off wavelength measurements of single mode optical fiber standards used in OTDR calibrations

This paper describes determination of the mode field diameter (MFD), and the cut-off wavelength of the single mode optical fiber standards used in OTDR calibrations, which was constructed in Optics Laboratory of National Metrology Institute of Turkey. Measurements of MFD were performed using computer controlled stepper motor unit with far field scanning (FFS) Method. For the same standard fibers, cut-off wavelength measurement was performed employing bend reference method, which is one of the transmitted power techniques. For both measurements, a nitrogen-cooled 5 mm InGaAs radiometer was used to detect optical flux. Detailed uncertainty analyses were presented for the MFD and cut-off measurements. While the total expanded uncertainties in MFD data at 1306.7 nm and 1550 nm were calculated as 0.8% and 1.0% (k=2), respectively, the total expanded uncertainty at determination of cut-off wavelength was found as 0.318% (k=2).