High-sensitivity cryogenic temperature sensors using pressurized fiber Bragg gratings

Cryogenic temperature sensing was studied using a pressurized fiber Bragg grating (PFBG). The PFBG was obtained by simply applying a small diametric load to a regular fiber Bragg grating (FBG), which was coated with polyimide of a thickness of 11 micrometers. The Bragg wavelength of the PFBG was measured at temperatures from 295 K to 4.2 K. A pressure-induced transition occurred at 200 K during the cooling cycle. As a result, the temperature sensitivity of the PFBG was found to be nonlinear and reach 24 pm/K below 200 K, more than three times the regular FBG. For the temperature change from 80 K to 10 K, the PFBG has a total Bragg wavelength shift of about 470 pm, 10 times more than the regular FBG. From room temperature to liquid helium temperature the PFBG gives a total wavelength shift of 3.78 nm, compared to the FBG of 1.51 nm. The effect of the coating thickness on the temperature sensitivity of the gratings is also discussed.

[1]  Michael A. Davis,et al.  Fiber grating sensors , 1997 .

[2]  Ralph P. Tatam,et al.  Strain response of fibre Bragg grating sensors at cryogenic temperatures , 2002 .

[3]  J. Sirkis,et al.  Effects of diametric load on fibre Bragg gratings fabricated in low birefringent fibre , 1996 .

[4]  Toru Mizunami,et al.  High-sensitivity cryogenic fibre-Bragg-grating temperature sensors using Teflon substrates , 2001 .

[5]  Meng-Chou Wu,et al.  Fabrication of self-apodized short-length fiber Bragg gratings. , 2003, Applied optics.

[6]  M. Froggatt,et al.  Distributed measurement of static strain in an optical fiber with multiple bragg gratings at nominally equal wavelengths. , 1998, Applied optics.

[7]  S. James,et al.  Strain response of fibre Bragg grating sensors at cryogenic temperatures , 2002, 2002 15th Optical Fiber Sensors Conference Technical Digest. OFS 2002(Cat. No.02EX533).

[8]  Ralph P. Tatam,et al.  Simultaneous independent temperature and strain measurement using in-fibre Bragg grating sensors , 1996 .

[9]  John P. Dakin,et al.  Discrimination between strain and temperature effects using dual-wavelength fibre grating sensors , 1994 .

[10]  Clinton Randy Giles,et al.  Lightwave applications of fiber Bragg gratings , 1997 .

[11]  S. Gupta,et al.  Fiber Bragg grating cryogenic temperature sensors. , 1996, Applied optics.

[12]  G.M. Williams,et al.  Hybrid fiber Bragg grating/long period fiber grating sensor for strain/temperature discrimination , 1996, IEEE Photonics Technology Letters.

[13]  K. Hill,et al.  Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication , 1978 .