[1] [1] K. Toge and F. Ito, “Recent research and development of optical fiber monitoring in communication systems,” Photonic Sensors, 2013, 3(4): 304–313.

[2] [2] J. Tiana, Y. Yaoa, Y. X. Suna, X. C. Xub, X. H. Zhaoa, and D. Y. Chen, “Flat broadband erbium-doped fiber ASE source based on symmetric nonlinear optical loop mirror,” Laser Physics, 2010, 20(8): 1760–1766.

[3] [3] M. K. Jazi, S. Shahi, M. J. Hekmat, H. Saghafifar, A. T. Khuzani, H. Khalilian, et al., “The evaluation of various designs upon C&L band super fluorescent sources based erbium doped fiber,” Laser Physics, 2013, 23(6): 553–559.

[4] [4] J. Yang, X. Meng, C. Liu, and C. Liu, “Gain-flattened two-stage L-band erbium-doped fiber amplifier by weak gain-clamped technique,” Optical Engineering, 2015, 54(3): 036107-1–036107-5.

[5] [5] H. Lin, W. Fan, and W. Han, “Broad gain of the Er/Al- doped fiber amplifier by pumping with a white light-emitting diode,” Journal of Luminescence, 2014 146(1): 87–90.

[6] [6] N. A. D. Huri, A. Hamzah, H. Arof, H. Ahmad, and S. W. Harun, “Hybrid flat gain c-band optical amplifier with zr-based erbium-doped fiber and semiconductor optical amplifier,” Laser Physics, 2011, 21(1): 202–204.

[7] [7] C. A. F. Marques, R. A. Oliveira, A. A. P. Pohl, and R. N. Nogueira, “Adjustable EDFA gain equalization filter based on a single LPG excited by flexural acoustic waves for future DWDM networks,” in International Conference on Fibre Optics and Photonics, 2012, 180: 3770–3774.

[8] [8] A. A. P. Pohl, R. A. Oliveira, R. E. D. Silva, C. A. F. Marques, P. D. T. Neves Jr, K. Cook, et al., “Advances and new applications using the acousto-optic effect in optical fibers,” Photonic Sensors, 2013, 3(1): 1–25.

[9] [9] X. Xue, W. Zhang, L. Yin, S. Wei, Sh. Gao, P. Geng, et al., “All-fiber intermodal Mach-Zehnder interferometer based on a long-period fiber grating combined with a fiber bitaper,” Optics Communications, 2012, 285: 3935–3938.

[10] [10] N. Kumar and K. Ramachandran, “Mach-Zehnder interferometer concatenated fiber loop mirror based gain equalization filter for an EDFA,” Optics Communications, 2013, 289(4): 92–96.

[11] [11] A. P. Zhang, S. Gao, G. Yan, and Y. Bai, “Advances in optical fiber Bragg grating sensor technologies,” Photonic Sensors, 2012, 2(1): 1–13.

[12] [12] K. Kalli, T. Allsop, K. Zhou, G. Smith, M. Komodromos, D. Webb, et al., “Sensing properties of femtosecond laser-inscribed long period gratings in photonic crystal fiber,” Photonic Sensors, 2011, 1(3): 228–233.

[13] [13] A. Singh, “Long period fiber grating based refractive index sensor with enhanced sensitivity using michelson interferometric arrangement,” Photonic Sensors, 2015, 5(2): 172–179.

[14] [14] Q. Huang, Y. Yu, Z. Ou, X. Chen, J. Wang, P. Yan, et al., “Refractive index and strain sensitivities of a long period fiber grating,” Photonic Sensors, 2014, 4(1): 92–96.

[15] [15] R. C. Chaves, A. D. A. P. Pohl, I. Abe, R. Sebem, and A. Paterno, “Strain and temperature characterization of LPGs written by CO2 laser in pure silica LMA photonic crystal fibers,” Photonic Sensors, 2015, 5(3): 241–250.

[16] [16] X. Xu, J. Tang, J. Zhao, K. Yang, C. Fu, Q. Wang, et al., “Post-treatment techniques for enhancing mode-coupling in long period fiber gratings induced by CO2 laser,” Photonic Sensors, 2015, 5(4): 339–344.

[17] [17] M. Melo and P. V. S. Marques, “Fabrication of tailored Bragg gratings by the phase mask dithering/moving technique,” Photonic Sensors, 2013, 3(1): 81–96.

[18] [18] J. Ju and W. Jin, “Long period gratings in photonic crystal fibers,” Photonic Sensors, 2012, 2(1): 65–70.

[19] [19] A. Singh, “Study of modeling aspects of long period fiber grating using three-layer fiber geometry,” Photonic Sensors, 2015, 5(1): 32–42.

[20] [20] Q. Li, F. Yan, P. Liu, W. Peng, G. Yin, and T. Feng, “Analysis of transmission characteristics of tilted long period fiber gratings with full vector complex coupled mode theory,” Photonic Sensors, 2012, 2(2): 158–165.

[21] [21] J. K. Bae, J. Bae, S. H. Kim, N. Park, and S. B. Lee, “Dynamic EDFA gain-flattening filter using two lpfgs with divided coil heaters,” IEEE Photonics Technology Letters, 2005, 17(6): 1226–1228.

[22] [22] V. Nascimento, J. D. Oliveira, V. B. Ribeiro, and A. C. Borndonalli, “Dynamic EDFA gain spectrum equalizer using temperature controlled optoceramic filter array,” in IEEE Microwave & Optoelectronics Conference (IMOC), Natal, 2011, pp. 273–276.

[23] [23] R. B. Shang, W. G. Zhang, W. B. Zhu, P. C. Geng, J. Ruan, S. C. Gao, et al., “Fabrication of twisted long period fiber gratings with high frequency CO2 laser pulses and its bend sensing,” Journal of Optics, 2013, 15(7): 75402–75407.

[24] [24] W. Jin and H. Xuan, “Rocking long period gratings in single mode fibers,” IEEE Lightwave Technology, 2013, 31(18): 3117–3122.