Quantitative in situ measurement of optical force along a strand of cleaved silica optical fiber induced by the light guided therewithin

TL;DR

This study introduces an optomechanical system to measure the net optical force on a silica fiber in situ, revealing the combined effects of facet emission and guided light tension, with force depending on optical power and fiber properties.

Contribution

It presents a novel experimental setup for in situ quantification of optical forces on fibers, highlighting the combined effects of facet emission and guided light tension, and identifying their fundamental dependencies.

Findings

Net force depends on optical power, refractive index, and light speed.

Both facet emission and guided light tension contribute to the force.

Force measurement aligns with theoretical predictions.

Abstract

We proposed an optomechanical system to quantify the net force on a strand of cleaved silica optical fiber in situ as the laser light was being guided through it. Four strands of the fiber were bond to both sides of a macroscopic oscillator, whose movements were accurately monitored by a Michelson interferometer. The laser light was propagating with variable optical powers and frequency modulations. Experimentally, we discovered that the driving force for the oscillator consisted of not only the optical force of the light exiting from the cleaved facets but also the tension along the fiber induced by the light guided therewithin. The net driving force was determined only by the optical power, refractive index of the fiber, and the speed of light, which pinpoints its fundamental origin.