Supercontinuum light source with adjustable spectral width by inducing mechanical stresses in photonic crystal fiber

Abstract

In this paper we show experimental results based on the study of a supercontinuum light source whose spectral width can be tuned in a range from ~748 nm to over 1420 nm while it maintains a good flatness. The proposed configuration for the supercontinuum source was developed using a relatively short piece of photonic crystal fiber (PCF) as the nonlinear medium pumped by a microchip Q-switched laser at 1064 nm. We demonstrated experimentally that the spectral width control on the supercontinuum source is made possible through the stress applied to the PCF used in the experimental setup, which induces birefringence and causes changes of polarization along the fiber. These phenomena are made possible by the application of bending and twist to the PCF in conjuntion with retarder plates inserted into the optical arrangement, which allows selecting the bandwidth of the white light source. Finally, a description of important features of the measured output spectrum is provided, and potential applications are proposed.