An Optical Fiber Tip

edu.cn). Abstract: An 12-m-long Bragg grating was engraved in an 5-m-diameter optical fiber tip by focused ion beam (FIB) milling. An 10-dB extinction was achieved at 1570 nm with only 11 indentations. The grating was used for temperature sensing, and it exhibited a temperature sensitivity of 22 pm=C. Index Terms: Fiber gratings, optical fiber devices, optical fiber sensors, temperature sensors. Since their discovery in 1978 [1], optical fiber gratings have found a variety of applications in telecom and sensing because of their relatively low cost, inherent self-referencing, and multiplexing/ demultiplexing capabilities. Over the last two decades, fiber Bragg gratings (FBGs) have been manufactured mainly by modifying the core refractive index using interferometric or point-by-point techniques; most of interferometric techniques use a phase mask and an ultraviolet (UV) laser [2] (typically excimer or frequency doubled Arþ ion) or femtosecond lasers (near infrared [3] or UV [4]). Gratings based on surface etched corrugations have also been demonstrated in etched fibers using photolithographic techniques [5]. However, all these gratings fabricated in thick fibers have wea