Micromachining FBG fabrication using point by point technique utilizing femto -second laser Abu Farzan Mitul Bohan Zhou Huiyu Zhao and Ming Han

2025-05-02 0 0 677.47KB 9 页 10玖币

侵权投诉

Micromachining & FBG fabrication using point by point technique utilizing

femto-second laser

Abu Farzan Mitul, Bohan Zhou, Huiyu Zhao and Ming Han

Electrical & Computer Engineering Department

Michigan State University

Abstract:

Fiber bragg gratings (FBG) has wide variety of applications in sensor and laser devices. In this work, we

have fabricated FBG using point by point (PbP) technique utilizing fs laser. FBGs spectral characteristics

were explored through the variation of grating length, fiber holder position, laser power and coated layer.

Fs FBG is fabricated on small mode field diameter fiber which shows enhancement of transmission

depth to 2.5 dB. The center wavelength shift is observed from 1520 nm to 1568 nm with the change in

translational stage speed. The fs FBGs can be utilized in high pressure sensing, high temperature sensing

and hazardous environment monitoring purposes.

Introduction:

Fiber Bragg gratings (FBGs) have wide variety of applications in optical fiber high temperature

sensing, optical telecommunications and an essential tool in fiber lasers to achieve robust,

monolithic cavity and narrow linewidth [1]. FBGs are widely accepted sensing device because

of it`s low cost, small size, immunity to electromagnetic interference and passive nature. In

recent years, researchers have shown FBGs to detect chemical gas, biological, physical

parameters e,g, strain, temperature, liquid level, transverse force, breath and heart rates and

torque etc [2]. FBGs are usually fabricated through the exposure of photo-sensitive optical fiber

to ultra-violet (UV) radiation by interfering two beams. Fabrication of FBGs using femtosecond

laser utilizes ultrafast laser with sub-picosecond pulse duration which provides an inherent three

dimensional resolution to fabrication and it directly modifies the glass structure inside the fiber

core. The quality of femtosecond FBGs is inferior to UV counterparts, but FBGs can be

inscribed onto single silica single mode fiber (SMF) without pre-processing such as

hydrogenation, reducing time and cost [3]. The fs laser pulses absorption mechanism allows the

the fs laser to modify the refractive index in transparent materials which enhances the functional

capabilities of FBG inscription. Here, non-linear absorption makes it possible to modify the non-

photosensitive material and inscribe FBGs through fiber plastic coating as it is transparent to IR

fs radiation. FBG can be inscribed directly by the use of fs laser without utilizing phase mask.

There are two main ways of FBG inscription i,e, (i) point-by-point (PbP) and (ii) core scanning

techniques. In this paper, we have utilized PbP technique to fabricate FBGs using fs laser. In PbP

technique, each pulse writes one grating pitch. Phase shift in the grating can be obtained by

adding a delay to the clock source which controls the laser pulse repetition rate [4]. Here, the

grating period is defined as the ratio of translation speed of the fiber to laser pulse repetition rate.

In this paper, we have investigated the development of grating structure on cover glasses for

micromachining purposes and fabricated 2nd order FBG using (Corning SMF-28) single mode

telecommunication fiber and small mode field diameter fiber.

Experimental setup and fabrication of FBG:

Figure 1 shows the experimental setup for 2nd order PbP FBG fabrication. The setup comprises

of astrella-usp-1k (𝜆 = 800 nm, f = 1 KHz, P = 5 W), ABL1000 Air-Bearing, Direct-Drive Linear

Stage ( total travel = 100 mm, straightness and flatness = ±0.4 µm), Objective lens (40X, NA=

0.75), DCU223C CCD camera, fiber holder and 3 axis nanomax piezo actuator (X=Y=Z=

4mm). broadband light source (Thorlabs, CLD1015) and the spectrum analyzer (OSA,

Yokogawa AQ6370C, Wavelength range: 600 to 1700nm) with a resolution of .020 nm were

employed to analyze the transmission spectrum after stretching the fs FBG. The maximum laser

pulse energy (~ 5 mJ) was attenuated by rotating a half waveplate which is incorporated with a

linear polarizer as shown in figure 1. PbP FBG fabrication is also analyzed using a telescope

system as shown in figure 2 which can provides the capability to change the beam size.

Figure 1: Schematic diagram of experimental setup of PbP fs FBG fabrication

Figure 2: fs beam size controlled using a convex-concave lens combination (telescope system)

文档加载中……请稍候！
如果长时间未打开，您也可以点击刷新试试。

下载文档到电脑，查找使用更方便

10 玖币 0人已下载

立即下载

摘要：

Micromachining&FBGfabricationusingpointbypointtechniqueutilizingfemto-secondlaserAbuFarzanMitul,BohanZhou,HuiyuZhaoandMingHanElectrical&ComputerEngineeringDepartmentMichiganStateUniversityAbstract:Fiberbragggratings(FBG)haswidevarietyofapplicationsinsensorandlaserdevices.Inthiswork,wehavefabricatedF...

展开>> 收起<<

Micromachining FBG fabrication using point by point technique utilizing femto -second laser Abu Farzan Mitul Bohan Zhou Huiyu Zhao and Ming Han.pdf

共9页,预览2页

还剩页未读，继续阅读

声明：本站为文档C2C交易模式，即用户上传的文档直接被用户下载，本站只是中间服务平台，本站所有文档下载所得的收益归上传人(含作者)所有。玖贝云文库仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对上载内容本身不做任何修改或编辑。若文档所含内容侵犯了您的版权或隐私，请立即通知玖贝云文库，我们立即给予删除！

Micromachining FBG fabrication using point by point technique utilizing femto -second laser Abu Farzan Mitul Bohan Zhou Huiyu Zhao and Ming Han

相关推荐

开通VIP享超值会员特权

作者详情

相关内容

热门标签

举报选择: