A fiber in-line reflective Mach–Zehnder interferometer is proposed and experimentally demonstrated, which is based on a tilted in-fiber beam splitter inscribed by a femtosecond laser. The beam splitter splits the incident light beam into two parts; one is directed to the fiber cladding-air interface, where it experiences total internal reflection and is directed to the fiber core. The other part of the light beam keeps traveling in the fiber core. The two parts of the light beams are recombined in the fiber core to generate interference before being reflected at the fiber cut end face. The device proposed is compact in size, robust in mechanical strength, easy in fabrication, and can be used for environmental refractive index sensing in a convenient manner.

中文翻译：

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基于倾斜式光纤分束器的在线反射型马赫曾德尔干涉仪

提出并通过实验证明了一种光纤在线反射型马赫曾德尔干涉仪，该干涉仪基于飞秒激光刻写的倾斜式光纤分束器。分束器将入射光束分为两部分：一类是针对光纤包层-空气界面，在该处它会经历全内反射，并针对光纤纤芯。光束的另一部分继续在光纤芯中传播。光束的两部分在光纤纤芯中重新组合以产生干涉，然后在光纤切割端面处反射。提出的装置尺寸紧凑，机械强度坚固，易于制造，并且可以以方便的方式用于环境折射率感测。