An in-line all-fiber etalon,formed by a self-enclosed Fabry-Pérot (F-P) cavity inside an optical fiber fabricated by using 157 nm laser micromachining,is demonstrated.The strain and temperature characteristics of the etalon sensor are investigated.The results show that the strain sensitivity is 1 mrad/μm and 5.2 pm/μm,and the linearity is 99.92% with two fixed point at a distance of 1 m.Furthermore,the temperature sensitivity is 0.13 mrad/℃ and 0.64 pm/℃ at the range of 18 ℃ to 500 ℃.Experimental results show that the etalon can meet versatile applications for stain measurement because of its perfect sensor characteristics,such as excellent interferometric fringe contrast of up to 30 dB,low thermal cross-sensitivity,great potential to realize mass-production,low cost,and super capability to operate in harsh environments.