Characteristic control of long period fiber grating (LPFG) fabricated by infrared femtosecond laser

doi:10.1007/s12200-012-0270-1

Front Optoelec

2012, Vol. 5

Issue (3) : 334-340 https://doi.org/10.1007/s12200-012-0270-1

RESEARCH ARTICLE

Characteristic control of long period fiber grating (LPFG) fabricated by infrared femtosecond laser

Xiaoyan SUN^1,2, Peng HUANG¹, Jiefeng ZHAO¹, Li WEI³, Nan ZHANG¹, Dengfeng KUANG¹, Xiaonong ZHU¹(

)

1. Institute of Modern Optics, Nankai University, Key Laboratory of Optical Information Science and Technology, Ministry of Education, Tianjin 300071, China; 2. College of Mechanical and Electrical Engineering, Central South University, State Key Laboratory of High Performance Complex Manufacturing, Changsha 410083, China; 3. Department of Physics & Computer Science, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada

Download: PDF(408 KB) HTML
Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks

Abstract

Long period fiber gratings (LPFGs) with different spectral characteristics were fabricated with 1 kHz, 50 fs laser pulses. The contrast of resonant rejection band can be significantly increased by a proper amount of axial stress along a fiber during laser writing or post-processing with lower energy density laser irradiation. Variations of focal condition, pulse energy of laser irradiation and the number of grating periods lead to the generation of resonance rejection band of LPFGs from single-peak to multi-peak plus larger out-of-band loss. The out-of-band loss is primarily caused by Mie scattering from the laser processed cites, and it can be reduced by decreasing the duty cycle of grating pitch instead of lowing down the actual power of laser irradiation.

Keywords long-period fiber grating (LPFG) infrared femtosecond laser out-of-band loss Mie scattering micro-nano-fabrication

Corresponding Author(s): ZHU Xiaonong,Email:xnzhu1@nankai.edu.cn

Issue Date: 05 September 2012

Cite this article:

Xiaonong ZHU,Jiefeng ZHAO,Li WEI, et al. Characteristic control of long period fiber grating (LPFG) fabricated by infrared femtosecond laser[J]. Front Optoelec, 2012, 5(3): 334-340.

URL:

https://academic.hep.com.cn/foe/EN/10.1007/s12200-012-0270-1
https://academic.hep.com.cn/foe/EN/Y2012/V5/I3/334

Fig.1 Schematic diagram of experimental setup for the fabrication of LPFGs. During laser writing, the fiber is translated along its axis and normal to the incoming laser beam focused by a 25× microscopic objective. A super continuum light source (Koheras SuperK) and an optical spectrum analyzer (OSA, Ando AQ6315E) are used for in situ monitoring the transmission spectrum of the LPFGs during laser writing

Fig.2 (a) Transmission spectra of LPFGs fabricated with 0 to 3 N axial stresses applied along the fiber respectively; (b) growth of transmission spectra as a function of length for 3 and 2 N pulling forces, respectively. In (b), for both forces of 3 and 2 N, the black curves are recorded when the grating length is 20 mm, and the red curves are measured when the grating length is 25 mm

Fig.3 Comparison of transmission spectra of LPFGs with (hollow round dots) and without (solid squares) post processing

Fig.4 Transmission spectra of LPFGs fabricated with a 10× objective and single pulse energy is 0.75 μJ

Fig.5 Evolution of LPFG transmission spectra for different total number of grating periods, indicated on the right of each plot. The traces are better viewed row by row, first starting from the one on the top left = 2, then to its right = 4, and then move to the bottom left = 6, next to it is the bottom right = 8, and then go back to the top left plot but now = 10 and so on, up to the spectrum associated with = 32 given in the bottom right plot

Fig.6 Microscopic image of light scattering from LPFGs when light from broadband light source is coupled into and propagating through fiber core

Fig.7 Transmission spectra of LPFGs written by 2 μJ laser pulses energy for three different duty cycles (Note that the grating period is 500 μm for all the gratings shown here, and thus 100/400 duty cycle means laser on for 100 μm and laser off for 400 μm)

1	Canning J. Fibre gratings and devices for sensors and lasers. Laser and Photonics Reviews , 2008, 2(4): 275–289 doi: 10.1002/lpor.200810010
2	James S, Tatam R. Optical fibre long-period grating sensors: characteristics and application. Measurement Science & Technology , 2003, 14(5): 49–62 doi: 10.1088/0957-0233/14/5/201
3	Jiang X L, Gu Z T. Design of a gas sensor based on a sensitive film coated phase-shifted longperiod fiber grating. Journal of Optics , 2010, 12(7): 075401 doi: 10.1088/2040-8978/12/7/075401
4	Viegas D, Carvalho J P, Coelho L, Santos J L, Araujo F M, Frazao O. Long-period grating fiber Sensor with in situ optical source for remote sensing. IEEE Photonics Technology Letters , 2010, 22(20): 1533–1535 doi: 10.1109/LPT.2010.2067208
5	Allsop T, Kalli K, Zhou K, Lai Y, Smith G, Dubov M, Webb D J, Bennion I. Long period gratings written into a photonic crystal fibre by a femtosecond laser as directional bend sensors. Optics Communications , 2008, 281(20): 5092–5096 doi: 10.1016/j.optcom.2008.07.001
6	Kondo Y, Nouchi K, Mitsuyu T, Watanabe M, Kazansky P G, Hirao K. Fabrication of long-period fiber gratings by focused irradiation of infrared femtosecond laser pulses. Optics Letters , 1999, 24(10): 646–648 doi: 10.1364/OL.24.000646 pmid:18073810
7	Martinez A, Dubov M, Khrushchev I, Bennion I. Photoinduced modifications in fiber gratings inscribed directly by infrared femtosecond irradiation. IEEE Photonics Technology Letters , 2006, 18(21): 2266–2268 doi: 10.1109/LPT.2006.884883
8	Martinez A, Khrushchev I Y, Bennion I. Direct inscription of Bragg gratings in coated fibers by an infrared femtosecond laser. Optics Letters , 2006, 31(11): 1603–1605 doi: 10.1364/OL.31.001603 pmid:16688234
9	Zhang N, Yang J J, Wang M W, Zhu X N. Fabrication of long-period fibre graings using 800 nm femtosecond laser pulses. Chinese Physics Letters , 2006, 23(12): 3281–3284 doi: 10.1088/0256-307X/23/12/044
10	Fujii T, Fukuda T, Ishikawa S, Ishii Y, Sakuma K, Hosoya H. Characteristics improvement of long-period fiber gratings fabricated by femtosecond laser pulses using novel positioning technique. In: Proceedings of Optical Fiber Communication Conference, Technical Digest (CD) (Optical Society of America) . 2004, THC6
11	Liu Y Q, Chiang K S. CO₂ laser writing of long-period fiber gratings in optical fibers under tension. Optics Letters , 2008, 33(17): 1933–1935 doi: 10.1364/OL.33.001933 pmid:18758569
12	Fertein E, Przygodzki C, Delbarre H, Hidayat A, Douay M, Niay P. Refractive-index changes of standard telecommunication fiber through exposure to femtosecond laser pulses at 810 nm. Applied Optics , 2001, 40(21): 3506–3508 doi: 10.1364/AO.40.003506 pmid:18360376
13	Hindle F, Fertein E, Przygodzki C, Dürr F, Paccou L, Bocquet R, Niay P, Limberger H G, Douay M. Inscription of Long-period gratings in pure silica and germane-silicate fiber cores by femtosecond laser irradiation. IEEE Photonics Technology Letters , 2004, 16(8): 1861–1863 doi: 10.1109/LPT.2004.831264
14	Eggleton B J, Kerbage C, Westbrook P S, Windeler R S, Hale A. Microstructured optical fiber devices. Optics Express , 2001, 9(13): 698–713 doi: 10.1364/OE.9.000698 pmid:19424310
15	Vengsarkar A M, Lemaire P J, Judkins J B, Bhatia V, Erdogan T, Sipe J E. Long-period fiber gratings as band-rejection filters. Journal of Lightwave Technology , 1996, 14(1): 58–65 doi: 10.1109/50.476137
16	Kim C S, Han Y, Lee B H, Han W T, Paek U C, Chung Y. Induction of the refractive index change in B-doped optical fibers through relaxation of the mechanical stress. Optics Communications , 2000, 185(4-6): 337–342 doi: 10.1016/S0030-4018(00)01045-2
17	Melle S M, Liu K X, Measures R M. Practical fiber-optic Bragg grating strain gauge system. Applied Optics , 1993, 32(19): 3601–3609 doi: 10.1364/AO.32.003601 pmid:20829986
18	Brambilla G, Fotiadi A A, Slattery S A, Nikogosyan D N. Two-photon photochemical long-period grating fabrication in pure-fused-silica photonic crystal fiber. Optics Letters , 2006, 31(18): 2675–2677 doi: 10.1364/OL.31.002675 pmid:16936854
19	Erdogan T. Fiber grating spectra. Journal of Lightwave Technology , 1997, 15(8): 1277–1294 doi: 10.1109/50.618322
20	Aslund M L, Nemanja N, Groothoff N, Canning J, Marshall G D, Jackson S D, Fuerbach A, Withford M J. Optical loss mechanisms in femtosecond laser-written point-by-point fibre Bragg gratings. Optics Express , 2008, 16(18): 14248–14254 doi: 10.1364/OE.16.014248 pmid:18773035
21	Schaffer C B, Garcia J F, Mazur E. Bulk heating of transparent materials using a high-repetition-rate femtosecond laser. Applied Physics A, Materials Science & Processing , 2003, 76(3): 351–354 doi: 10.1007/s00339-002-1819-4
22	Eaton S M, Zhang H B, Herman P R, Yoshino F, Shah L, Bovatsek J, Arai A. Heat accumulation effects in femtosecond laser-written waveguides with variable repetition rate. Optics Express , 2005, 13(12): 4708–4716 doi: 10.1364/OPEX.13.004708 pmid:19495387

Viewed

Full text

Abstract

Cited

Shared

Discussed