A novel fiber Bragg grating (FBG) with two transmission dips in 1310-and 1550-nm regions is proposed and inscribed by an infrared femtosecond laser.Formed by multi-photon ionization,this type of grating can withstand temperature as high as 800℃ which makes it suitable for harsh environment sensing.In addition,the temperature and strain affect these two dips in different ways,which enables simultaneous strain and temperature sensing.The fabrication,spectrum characterization,and temperature performance of this grating are introduced.
