High-Temperature Sensor Based on 45° Tilted Fiber End Fabricated by Femtosecond Laser

In this letter, we proposed and experimentally demonstrated a novel fiber sensing head based on 45° tilted fiber end for high-temperature measurement. The sensing head was fabricated by femtosecond laser using a line-scanning method. The light is mainly split into two beams at the 45° tilted fiber end, which forms a Michelson interference with a fringe visibility of
$\sim 20$
dB. The experimental consequences show that the sensing head can withstand high temperature up to 800 °C and the temperature sensitivity is 19.7 pm/°C at 600 °C and 1605 nm. The merits of the sensing head are extremely compact, low cost, simple in configuration, easy for batch fabrication, and available to detect the temperature at precise location in microsize space.