SOA-based fiber ring laser with seed of DFB wavelength scanning for relative humidity measurement using an air-guided photonic crystal fiber

作者：Noor M Y Mohd^*; Khalili N; Peng G D

来源：Measurement Science and Technology, 2013, 24(8): 085203.

DOI：10.1088/0957-0233/24/8/085203

• SOA ring laser
• wavelength scanning
• air-guided photonic bandgap fiber
• gas humidity sensing
• water vapor absorption

We propose a novel ring laser for non-hygroscopic coating relative humidity (RH) fiber sensor by means of infrared absorption spectroscopy. A semiconductor optical amplifier (SOA)-based fiber ring laser is used in this scheme. No tunable optical filter is required for the ring laser scheme as wavelength scanning is introduced in the ring using a distributed feedback (DFB) laser. An air-guided photonic crystal fiber (AGPCF) is included in the ring cavity that acts as a sensing head. The detection of gas humidity inside the air holes of AGPCF is determined by DFB wavelength scanning around 1368.59 nm water vapor absorption peak with SOA as a gain medium in the ring. We have experimentally implemented the wavelength scanning of SOA-based fiber ring laser scheme with an AGPCF sensing head of 5 cm and a small gap between single mode fiber and AGPCF to allow air diffusion in and out of the air holes inside the AGPCF. The sensitivity of the sensor is increased from 2.47 to 10.93 mV/1% RH over the range from 0 to 90% RH when the non-lasing mode (single-pass absorption spectroscopy) of the sensor is changed into the lasing mode (multi-pass absorption spectroscopy).

• 出版日期2013-8