Fiber Inline Mach–Zehnder Interferometer Based On Femtosecond Laser Inscribed Waveguides

Femtosecond laser radiatio n can produce permanent refractive index mod ificatio ns in a localized region ins ide the silica mater ia ls,and has been used to inscribe wa veguides ins ide the s ilica mater ia ls.Compared with CO₂laser and UV laser exposure method s,the femtosecond laser inscr iption possesses the advantages of high processing precis ion and good surface smoothness.In recent years,with the rapid developme nt of fe mtosecond laser writing waveguide techno logy,vario us nove l optica l fiber devices have been introduced.This thes is focuses on the use of femtosecond laser to fabricate waveguides in optica l fibers to form a Mach-Zehnder inter fero meter.The preparation techniq ues and related princ iples o f such devices are summar ized and their potential applications are explored.The content of this paper consists of the following four parts.1.In the introduction,we described the app licatio n o f fe mtosecond laser in micro fabr icatio n,the deve lopme nt background,research status and research significa nce are described.Fina lly,a summar y is made to introduce the purpose and significance of the work involved in this pap er.2.We propose and experime nta lly demonstrate a new type of fiber inline Mach–Zehnder inter fero meter based on fe mtosecond laser inscr ibed waveguides.The fabr icatio n process and princ iple o f the device are described in detail,and the potential application of the device is studied.3.We proposed a new type of fiber in-line Mach-Zehnder inter ferometer based on a pair of short sections of wave guide.The temperature,stra in,and re fractive index e xperime nts are perfor med,outcomes are analyzed respective ly.And the exper imenta l results of fitting line are drawn for the sensitivity of the sensor to measure different environmental factors.4.We also proposed a new type of fiber in-line Mach-Zehnder inter ferometer based on fe mtosecond laser inscr ibed straight wave guide in no-core fiber.High te mperature exper iment is operated;the transmiss ion spectrum was monitored.And the bending sensitivity is also studied.In this paper,the mentioned devices based on femtosecond laser writing wave guides are proposed.These devices are novel in str ucture,robust,and sensitive,and have broad applicatio n prospects in fiber sensing.We believe that the in-fiber wave guide based devices can play the role an important building block for future integrated“all-in-fiber”photonics circuits and have high potential in“lab-in-fiber”applications.