Highly Birefringent Slot-Microfiber

We propose a possible approach to realize a highly birefringent slot microfiber by postprocessing a circular microfiber (CMF). The shape can be fabricated with very high repeatability, reliability, and accuracy. Light field can be enhanced and confined in the nanometer-wide low index slot, and the birefringence achieves as high as 4 × 10
^-2
. The slot-microfiber has the advantages both of a microfiber and a slot waveguide. It is perfect for miniature fiberized polarization manipulation devices and its unique geometry can also greatly enhance the refractive index sensitivity (nearly ten times higher than that of CMFs) for evanescent-field-based gas sensors.