Micronewton nanofiber force sensor using Brillouin scattering

Stretch tuning of dispersion in optical microfibers

Dispersion management is vital for nonlinear optics and ultrafast lasers. We demonstrate that group velocity dispersion (GVD, or second-order dispersion, i.e., β2) and group delay dispersion (GDD) in optical microfibers can be tuned simply by stretch due to their remarkable features of small diameter and diameter-dependent dispersion. We experimentally demonstrate that a pulling force of just a few mN would elongate the optical microfibers by up to 5%, bringing a significant change in the β2 and GDD. This change can be increment or decrement, lying on the diameter of optical microfibers. Therefore, 10-cm-long optical microfibers would provide a GDD change of 104 fs2 when elongated by 5%, well in the elastic limit. Remarkably, this change is equivalent to the GDD (not GDD change) provided by a 0.5-m-long single-mode fiber. Experimental results and simulations show that the GDD change is due to the interplay between elongation, diameter shrink, and refractive index decrease. Benefited from the easy manipulation, tiny pulling force required, and full integration with conventional optical fibers, stretch tuning of dispersion in optical microfibers would find applications in dispersion management for ultrafast lasers and nonlinear optics.

Optical nanofibers for signal delaying

In this abstract, we purpose an optical delay line based on optical nanofibers. Silica high elasticity and the low pulling force required to stretch a nanofiber allow to get optical delays up to 20 picoseconds with a 10 centimeter-long optical nanofiber at telecommunications wavelength.