Abstract: Provided are methods, systems, and apparatus related to a gas detector (100, 402, 802) and a gas detector calibration cap (200, 300, 404, 703, 804). The gas detector calibration cap includes a cap body (202, 302), a first cap wing (204, 304), a second cap wing (206, 306), and an extended strip (216, 316) for opening the gas detector by inserting the extended strip in a groove (106, 707, 808) of the gas detector. The extended strip allows a worker to easily open the gas detector housing, thus improving the speed and reliability of servicing the gas detector while eliminating the potential additional cost on a separated tool for opening the gas detector housing.

Abstract: Provided are methods, systems, and apparatus related to a gas detector (100, 402, 802) and a gas detector calibration cap (200, 300, 404, 703, 804). The gas detector calibration cap includes a cap body (202, 302), a first cap wing (204, 304), a second cap wing (206, 306), and an extended strip (216, 316) for opening the gas detector by inserting the extended strip in a groove (106, 707, 808) of the gas detector. The extended strip allows a worker to easily open the gas detector housing, thus improving the speed and reliability of servicing the gas detector while eliminating the potential additional cost on a separated tool for opening the gas detector housing.

Abstract: A thee port polarization beam splitter is disclosed which utilizes only two GRIN lenses. Two beams are split by a bireferingent crystal into two orthogonally linear polarized parallel sub-beams. The two parallel beams are redirected to converge to a single same location at an end face of the GRIN lens by a roof prism and are coupled by the same lens to two optical fibers held in a fiber tube physically coupled to the GRIN lens.