Photosensitivity and thermal stability of UV- induced fiber Bragg gratings in phosphate glass fibers

The photosensitivity of highly Er/Yb doped and undoped phosphate glass fibers is characterized under irradiation with intense pulsed 193 nm light from an ArF excimer laser through a phase mask. The ultraviolet photosensitivity of the active fibers is shown to be roughly half that of the passive fibers. We also demonstrate that the strong growth of the fiber Bragg grating reflectivity observed upon heating at temperatures between 100 – 250 °C is directly related to the UV irradiation time, but not to the size of the index modulation of the seed grating or even to the fiber type (Er/Yb doped or undoped). The conditions to reliably obtain final index modulations amplitudes between 5 and 10 × 10 are given. ©2014 Optical Society of America OCIS codes: (060.3735) Fiber Bragg gratings; (060.2290) Fiber materials; (060.3738) Fiber Bragg gratings, photosensitivity; (120.6810) Thermal effects. References and links 1. P. Laporta, S. Taccheo, S. Longhi, O. Svelto, and C. Svelto, “Erbium–ytterbium microlasers: optical properties and lasing characteristics,” Opt. Mater. 11(2-3), 269–288 (1999). 2. L. Fletcher, J. Witcher, N. Troy, S. T. Reis, R. K. Brow, R. M. Vazquez, R. Osellame, and D. M. Krol, “Femtosecond laser writing of waveguides in zinc phosphate glasses,” Opt. Mater. Express 1(5), 845–855 (2011). 3. D. Grobnic, S. J. Mihailov, R. B. Walker, C. W. Smelser, C. Lafond, and A. Croteau, “Bragg gratings made with a femtosecond laser in heavily doped Er–Yb phosphate glass fiber,” IEEE Photon. Technol. Lett. 19(12), 943– 945 (2007). 4. M. Sozzi, A. Rahman, and S. Pissadakis, “Non-monotonous refractive index changes recorded in a phosphate glass optical fibre using 248nm, 500fs laser radiation,” Opt. Mater. Express 1(1), 121 (2011). 5. P. Hofmann, C. Voigtlander, S. Nolte, N. Peyghambarian, and A. Schülzgen, “550-mW output power from a narrow linewidth all-phosphate fiber laser,” J. Lightwave Technol. 31(5), 756–760 (2013). 6. J. Albert, A. Schülzgen, V. L. Temyanko, S. Honkanen, and N. Peyghambarian, “Strong Bragg gratings in phosphate glass single mode fiber,” Appl. Phys. Lett. 89(10), 101127 (2006). 7. R. M. Rogojan, A. Schülzgen, N. Peyghambarian, A. Laronche, and J. Albert, “Photo-thermal gratings in Er/Yb-doped core phosphate glass single mode fibers,” in Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides (OSA, 2007), p. BTuC3. 8. L. Xiong, P. Hofmann, A. Schülzgen, N. Peyghambarian, and J. Albert, “Photo-thermal growth of unsaturated and saturated Bragg gratings in phosphate glass fibers,” in Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides (OSA, 2010), p. BTuB1. 9. A. Schülzgen, L. Li, D. Nguyen, Ch. Spiegelberg, R. M. Rogojan, A. Laronche, J. Albert, and N. Peyghambarian, “Distributed feedback fiber laser pumped by multimode laser diodes,” Opt. Lett. 33(6), 614–616 (2008). 10. L. Li, A. Schülzgen, X. Zhu, J. V. Moloney, J. Albert, and N. Peyghambarian, “1 W tunable dual-wavelength emission from cascaded distributed feedback fiber lasers,” Appl. Phys. Lett. 92(5), 051111 (2008). 11. A. Hidayat, Q. Wang, P. Niay, M. Douay, B. Poumellec, F. Kherbouche, and I. Riant, “Temperature-induced reversible changes in the spectral characteristics of fiber Bragg gratings,” Appl. Opt. 40(16), 2632–2642 (2001). 12. K. Seneschal, F. Smektala, B. Bureau, M. Le Floch, S. Jiang, T. Luo, J. Lucas, and N. Peyghambarian, “Properties and structure of high erbium doped phosphate glass for short optical fibers amplifiers,” Mater. Res. Bull. 40(9), 1433–1442 (2005). 13. S. Bandyopadhyay, J. Canning, M. Stevenson, and K. Cook, “Ultrahigh-temperature regenerated gratings in boron-codoped germanosilicate optical fiber using 193 nm,” Opt. Lett. 33(16), 1917–1919 (2008). #211551 $15.00 USD Received 1 May 2014; revised 11 Jun 2014; accepted 11 Jun 2014; published 23 Jun 2014 (C) 2014 OSA 1 July 2014 | Vol. 4, No. 7 | DOI:10.1364/OME.4.001427 | OPTICAL MATERIALS EXPRESS 1427 14. D. J. Little, M. Ams, P. Dekker, G. D. Marshall, and M. J. Withford, “Mechanism of femtosecond-laser induced refractive index change in phosphate glass under a low repetition-rate regime,” J. Appl. Phys. 108(3), 033110 (2010). 15. S. Gross, M. Ams, G. Palmer, C. T. Miese, R. J. Williams, G. D. Marshall, A. Fuerbach, D. G. Lancaster, H. Ebendorff-Heidepriem, and M. J. Withford, “Ultrafast laser inscription in soft glasses: a comparative study of athermal and thermal processing regimes for guided wave optics,” Int. J. Appl. Glas. Sci. 3(4), 332–348 (2012). 16. R. Kashyap, Fiber Bragg Gratings, 2nd edition (Academic Press, 2009). 17. S. Yliniemi, S. Honkanen, A. Ianoul, A. Laronche, and J. Albert, “Photosensitivity and volume gratings in phosphate glasses for rare-earth-doped ion-exchanged optical waveguide lasers,” J. Opt. Soc. Am. B 23(12),