Fibre-coupled tunable source based on a supercontinuum laser for the spectral characterisation of fibre optics components and systems

Abstract

Abstract We present a measurement system, traceable to the International System of Units, for the calibration of the spectral responsivity (SR) of fibre-coupled photodetectors and power meters, as well as for the measurement of the spectral properties of fibre optics components. The system, based on a supercontinuum laser combined with a two-stage tunable filter, is continuously tunable in a spectral range spanning from 700 nm to 1800 nm. The typical full width half maximum (FWHM) spectral width is of about 1.3 nm, with an in-fibre power level of up to 1 mW. In a single mode geometry, the expanded uncertainty is as low as 0.7% for the SR calibration and 0.6% for the spectral properties calibration. Uncertainties of about 1% were estimated for both types of measurements in a multi mode geometry. Application fields of this versatile system range from telecommunication to sensors and to rapidly growing domains like quantum communication and cryptography.