Lyot Filter With Femtosecond Laser-Induced High Birefringence Single-Mode Fiber for Torsion, Transverse Load and Temperature Sensing

Bo Huang,Chun Mao,Ying Wang

doi:10.1109/access.2020.2968729

Bo Huang, Chun Mao + Show 1 more

Open Access

https://doi.org/10.1109/access.2020.2968729

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Abstract

We propose and experimentally demonstrate an all-fiber Lyot filter with femtosecond laser-induced high birefringence single-mode fiber (SMF) for torsion, transverse load and temperature sensing. With the femtosecond-laser processing technique, the SMF with the birefringence of 2.81 × 10 -4 is manufactured by directly writing a straight cladding stress track parallel with fiber core and employed to form an all-fiber Lyot filter for sensing application. The sensitivities of the all-fiber Lyot filter with respect to torsion, transverse load and temperature are found to be -4265.669 nm/(rad/mm), -321.004 nm/(N/mm), and 0.271 nm/°C, respectively. The experimental results are powerful proof of the excellent performance of the femtosecond laser-induced high birefringence SMF based all-fiber Lyot filter for sensing application, which not only adds significantly new and important results to the fields of optical sensing, but also develops the application fields of femtosecond-laser processing technique and all-fiber Lyot filter.

Highlights

INTRODUCTIONAs a kind of fiber device that can produce a passband at any wavelength in the transmission spectrum, has a widespread application in diverse fields, such as optical fiber communication, fiber laser, fiber sensing, and etc
Optical fiber transmission filter, as a kind of fiber device that can produce a passband at any wavelength in the transmission spectrum, has a widespread application in diverse fields, such as optical fiber communication, fiber laser, fiber sensing, and etc
The achieved birefringence in the single-mode fiber (SMF) is up to ∼2.81×10−4, which is comparable to the birefringence in commercially available polarizationmaintaining fiber (PMF)

Summary

INTRODUCTION

As a kind of fiber device that can produce a passband at any wavelength in the transmission spectrum, has a widespread application in diverse fields, such as optical fiber communication, fiber laser, fiber sensing, and etc. Bulk polarizers employed in the aforementioned two forms of Lyot filters result in high insertion loss and bulky structure. To address this issue, all-fiber Lyot filter constructed with commercially available PMF based birefringence medium and 45◦ tilted fiber gratings based fiber polarizer are reported [13], [16]. An all-fiber Lyot filter based on femtosecond laser-induced high birefringence SMF have been proposed. With the femtosecond-laser processing technique, a straight cladding stress track parallel with fiber core is fabricated, which introduces the asymmetrical stress distribution, thereby resulting in the come into being of the birefringence in the SMF. With the formation of the cladding stress track, the previous symmetric stress distribution in fiber becomes asymmetrical, thereby resulting in the come into being of the birefringence n in the SMF [22]–[25]

DEVICE FABRICATION AND WORKING PRINCIPLE

CONCLUSION