Sub-micron silica diaphragm-based fiber-tip Fabry-Perot interferometer for pressure measurement

We demonstrate a sub-micron silica diaphragm-based fiber-tip Fabry-Perot interferometer for pressure sensing applications. The thinnest silica diaphragm, with a thickness of similar to 320 nm, has been achieved by use of an improved electrical arc discharge technique. Such a sub-micron silica diaphragm breaks the sensitivity limitation imposed by traditional all-silica Fabry-Perot interferometric pressure sensors and, as a result, a high pressure sensitivity of similar to 1036 pm/MPa at 1550 nm and a low temperature cross-sensitivity of similar to 960 Pa/degrees C are achieved when a silica diaphragm of similar to 500 nm in thickness is used. Moreover, the all-silica spherical structure enhanced the mechanical strength of the micro-cavity sensor, making it suitable for high sensitivity pressure sensing in harsh environments. (C) 2014 Optical Society of America