Evanescent field refractometry in planar optical fiber.

Christopher Holmes,Rex H S Bannerman,Alan C Gray,Peter G R Smith,James C Gates,Paul C Gow,Lewis G Carpenter,Alexander Jantzen

doi:10.1364/ol.43.000791

Abstract

This Letter demonstrates a refractometer in integrated optical fiber, a new optical platform that planarizes fiber using flame hydrolysis deposition (FHD). The unique advantage of the technology is survivability in harsh environments. The platform is mechanically robust, and can survive elevated temperatures approaching 1000°C and exposure to common solvents, including acetone, gasoline, and methanol. For the demonstrated refractometer, fabrication was achieved through wet etching an SMF-28 fiber to a diameter of 8μm before FHD planarization. An external refractive index was monitored using fiber Bragg gratings (FBGs), written into the core of the planarized fiber. A direct comparison to alternative FBG refractometers is made, for which the developed platform is shown to have comparable sensitivity, with the added advantage of survivability in harsh environments.

Highlights

The integrated optical fiber (IOF) platform, illustrated, is composed of an optical fiber bound to a planar substrate through use of flame hydrolysis deposition (FHD)
This Letter reports on a new passive planar optical platform termed integrated optical fiber (IOF)
Since flame hydrolysis deposition (FHD) glass is of optical quality, it is suitable for direct optical interaction

Summary

Introduction

The IOF platform, illustrated, is composed of an optical fiber bound to a planar substrate through use of flame hydrolysis deposition (FHD). To the best of our knowledge, this Letter is the first to report direct optical interaction between the fiber core and the FHD binding medium. The evanescent field of the planarized fiber is exposed and a Bragg grating used to infer external refractive index.

Results

Conclusion