Supercontinuum (SC) sources offer very significant advantages for imaging and characterization of materials: full VIS-NIR spectrum availability, high spectral power density, reduced temporal coherence, among others. Certain applications require a very accurately customized emission spectrum, which in turn requires reliable tools to measure the dispersion spectra of the microstructured optical fiber of the SC source with very high spectral resolution and very short acquisition time. This measurement to be done ideally on the fly, while manufacturing the fiber, in order to fine tune the drawing variables to match the aimed dispersion profile in real time. In this work we present an interferometric method to measure chromatic dispersion using a pulsed FYLA SCT1000 supercontinuum. Very high-resolution dispersion measurement is obtained by optimization of the visibility of interferometric fringes, which is achieved by a fast synchronization of pulses overlapping.
FYLA SCT1000 Supercontinuum offers a very broadband emission with SPD close to 1 mW/nm, consisting of a train of white pulses of few ps timewidth, trigger output for synchronized measurements and very stable emission, with full spectrum average power stability < 0.5% and peak to peak stability < 1% in VIS region and < 0.6% in NIR region (stabilities refer to standard deviation over mean value). The sample to measure, which can be an optical fiber or any photonic device, is placed in one of the arms of a Michelson interferometer. Interferences obtained with different displacements give values of dispersion at different wavelengths. The standard way is to use a lamp or a SLED at each band [1,2]. This makes the measurement long and tedious. Lamps or SLEDs can be replaced by a single FYLA SCT1000 to obtain the dispersion curve in a fast and very robust way. Since the source is pulsed with a fixed rep rate, delay can be easily controlled to overlap properly light from arms of the interferometer. With a single source, the complete dispersion curve is obtained with resolution below 1 nm. In this work this synchronous interferometric method to measure dispersion is used to optimize the design and manufacture of microstructured optical fibers through an iterative protocol implemented in the fiber drawing process.