NIST has completed commissioning a new, state-of-the-art cryogenic primary standard for optical fibre power measurement and calibration. It establishes for the first time, a direct traceability route between the device under test and primary standard. Two silicon micromachined planar detectors, with vertically aligned carbon nanotube absorbers, thin film tungsten heaters and superconducting resistive transition edge temperature transducers, form the basis of the radiometer. Magnetic phase change thermal filters ensure noise-free operation at 7.6 K. Measurement repeatability below 50 ppm is routinely achieved during a measurement cycle of 30 min. The system operates at a nominal radiant power level of 200 µW (−7 dBm). The expanded measurement uncertainty at k = 2 is 0.4%, a 20% improvement on NIST's current optical fibre power Calibration and Measurement Capability.The performance of the new standard was established by comparing it to our current standard, using four transfer detectors, at nominal wavelengths 850 nm, 1295 nm and 1550 nm. The comparison agreed within the combined expanded measurement uncertainty of 0.6%. Whilst the new standard is intended primarily to service the telecommunications industry, it is limited in use only by available sources and optical fibre.

We demonstrate the capability to measure the absolute power responsivity of optical fiber-coupled detectors at an expanded uncertainty of 0.1%, by direct comparison with a cryogenic primary standard. To facilitate synchronous power measurements, commercial all-fiber beam-splitters direct laser diode light simultaneously to the device under test and the primary standard. We investigate the use of single-mode, polarisation maintaining, and photonic crystal fibers to access the cryogenic standard, and report a reduction in the temperature dependent effective refractive index of these fibers of 0.1%, 0.15% and 0.3% respectively in going from room temperature to 5 K. We also evaluate the polarisation dependent loss of the beam-splitters, the stability of the beam-splitter ratio between the cryogenic detector and the device under test and the temporal and modal stability of the Fabry-Pérot laser diode sources. It is shown that the stability of the optical fiber beam-splitters limits the overall performance of the measurement system to an expanded uncertainty of 0.1%.

Here we report on the first CENAM realization of the phase-shift method for chromatic dispersion measurements in mono-mode dispersion-shifted optical fibers used for the telecommunications C-band (1 530 nm to 1 565 nm). This chromatic dispersion measurement and calibration capability development at CENAM will provide the Mexican telecommunications industry with a formally established SI unit's traceability source, thus enhancing this rapidly growing and high impact economic sector competitiveness in Mexico. We also identified a 40 MHz modulation frequency, a 2.5 nm wavelength step and the 1 535 nm to 1 570 nm wavelength scanning range, as the optimum experimental parameters that have to be set in order to obtain experimental data which numerical Sellmeier polynomials fittings produce representative determinations for the group delay and the chromatic dispersion. We also obtained 1 549.388 nm ± 0.098 nm, for coverage factor k=1, for the zero dispersion wavelength, and 0.719 7 ps·nm -2 ± 0.005 5 ps·nm -2 , (k=1), for the zero dispersion slope of the tested optical fiber.

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