Sensing change

A compact one-fibre solution for temperature compensated refractive index measurement has been demonstrated. The first femtosecond laser-fabricated refractive index sensor without material removal that compensates for changes in temperature has been demonstrated by the researchers. The researchers devised a fibre Mach-Zehnder interferometer structure with a femtosecond laser irradiated spot and a taper as the two beam-steering elements of the interferometer. This device, which is compact, simple to use, easy to fabricate and low in cost, could be employed for refractive index sensing in a wide range of practical applications.