[1] [1] J R Vazquez de Aldana, P Moreno, L Roso. Ultrafast lasers: A new frontier for optical materials processing [J]. Opt Mater, 2012, 34(3): 572-578.

[2] [2] R G Rafaelf, M Eric. Femtosecond laser micromaching in transparent materials [J]. Nature Photonics, 2008, 2(4): 219-225.

[3] [3] K M Davis, K Miura, N Sugimoto, et al.. Writing waveguides in glass with a femtosecond laser [J]. Opt Lett, 1996, 21(21): 1729-1731.

[4] [4] B C Stuart, M D Feit, A M Rubenchik, et al.. Laser-induced damage in dielectrics with nanosecond to subpicosecond pulses [J]. Phys Rev Lett, 1995, 74(12): 2248-2251.

[5] [5] M Lenzner, J Kruger, S Sartania, et al.. Femtosecond optical breakdown in dielectrics [J]. Phys Rev Lett, 1998, 80(18): 4076-4079.

[6] [6] C B Schaffer, A Brodeur, J F Garcia, et al.. Micromachining bulk glass by use of femtosecond laser pulses with nanojoule energy [J]. Opt Lett, 2001, 26(2): 93-95.

[7] [7] C B Schaffer, J F Garcia, E Mazur. Bulk heating of transparent materials using a high repetition-rate femtosecond laser [J]. Appl Phys A, 2003, 76(3): 351-354.

[8] [8] Hou Fang, Li Weinan, Bai Jing, et al.. Femtosecond-laser-written waveguide in magnetic-optical glass [J]. Acta Optica Sinica, 2013, 33(3): 0314002.

[9] [9] Xuewen Long, Jing Bai, Xin Liu, et al.. Buried waveguide in neodymium-doped phosphate glass obtained by femtosecond laser writing using a double line approach [J]. Chin Opt Lett, 2013, 11(10): 102301.

[10] [10] Y Jia, F Chen, J R Vázquez de Aldana, et al.. Efficient continuous-wave laser operation at 1064 nm in NdYVO4 cladding waveguides produced by femtosecond laser inscription [J]. Opt Express, 2012, 20(4): 16801-16806.

[11] [11] Long Xuewen, Bai Jing, Liu Xin, et al.. Inscription of waveguides in terbium gallium garnet using femtosecond laser [J]. Acta Optica Sinica, 2014, 34(4): 0432002.

[12] [12] A Benayas, W F Silva, C Jacinto, et al.. Thermally resistant waveguides fabricated in NdYAG ceramics by crossing femtosecond damage filaments [J]. Opt Lett, 2010, 35(18): 330-332.

[13] [13] T Calmano, A G Paschke, J Siebenmorgen, et al.. Characterization of an Yb:YAG ceramic waveguide laser, fabricated by the direct femtosecond-laser writing technique [J]. Appl Phys A, 2011, 103(1): 1-4.

[14] [14] G Cheng, K Mishchik, C Mauclair, et al.. Ultrafast laser photoinscription of polarization sensitive devices in bulk silica glass [J]. Opt Express, 2009, 17(12): 9515-9525.

[15] [15] Bai Jing, Long Xuewen, Liu Xin, et al.. Embedded optical waveguides fabricated in SF10 glass by low-repetition-rate ultrafast laser [J]. Appl Opt, 2013, 52(30): 7288-7294.

[16] [16] Li Dongjuan, Lin Ling, Lü Baida, et al.. Polarization-dependent optical guiding in low repetition frequency femtosecond laser photowritten type II fused silica waveguides [J]. Acta Optica Sinica, 2013, 33(5): 0532001.

[17] [17] G D Marshall, M Ams, M J Withford. Direct laser written waveguide-Bragg gratings in bulk fused silica [J]. Opt Lett, 2006, 31(18): 2690-2691.

[18] [18] J Liu, Z Zhang, S Chang, et al.. Directly writing of 1-to-N optical waveguide power splitters in fused silica glass using a femtosecond laser [J]. Opt Commun, 2005, 253(4-6): 315-319.

[19] [19] C Mauclair, G Cheng, N Huot, et al.. Dynamic ultrafast laser spatial tailoring for parallel micromachining of photonic devices in transparent materials [J]. Opt Express, 2009, 17(5): 3531-3542.

[20] [20] A M Streltsov, N F Borrelli. Fabrication and analysis of a directional coupler written in glass by nanojoule femtosecond laser pulses [J]. Opt Lett, 2001, 26(1): 42-43.

[21] [21] S Taccheo, G D Valle, R Osellame, et al.. ErYb-doped waveguide laser fabricated by femtosecond laser pulses [J]. Opt Lett, 2004, 29(22): 2626-2628.

[22] [22] Bai Jing, Long Xuewen, Liu Xin, et al.. Femtosecond laser written waveguide in Yb3+:Phosphate glass and waveguide lasing [J]. Acta Optica Sinica, 2013, 34(4): 0432003.

[23] [23] P Lacovara, H K Choi, C A Wang, et al.. Room-temperature diode-pumped Yb:YAG lasers [J]. Opt Lett, 1991, 16(14): 1089-1091.

[24] [24] M Ross. YAG laser operation by semiconductor laser pumping [J]. Proc IEEE, 1968, 56(2): 196-197.

[25] [25] Qiu Hongwei, Yang Peizhi, Zhong Heyu, et al.. Influence of annealing and doping on Yb:YAG [J]. Chinese J Lasers, 2002, 29(5): 439-443.

[26] [26] Yang Peizhi, Deng Peizhen, Xu Jun, et al.. Spectroscopy and laser performance of Yb3+ doped YAG crystal [J]. Acta Optica Sinica, 1999, 19(1): 132-135.

[27] [27] J Burghoff, S Nolte, A Tunnermann. Origins of waveguiding in femtosecond laser-structured LiNdO3 [J]. Appl Phys A, 2007, 89(1): 127-132.

[28] [28] F Caccavale, F Segato, I Mansour, et al.. A finite differences method for the reconstruction of refractive index profiles from near-field measurements [J]. J Lightwave Technol, 1998, 16(7): 1348-1353.