[1] F. Tan, F. X.Yu and L. L.Wang, Journal of Russian Laser Research 35, 295 (2014).

[2] Yufei Ma, Xin Yu, Frank K. Tittel and Xudong Li, Optics Communications 285, 1911 (2012).

[3] Zuo-han Li, Ji-ying Peng, Yi Zheng, Ye Yang and Jin-hua Kou, Optoelectronics Letters 10, 423 (2014).

[4] A. Agnesi, A. Guandalini, G. Reali, S. Dell'Acqua and G. Piccinno, Optics Letters 29, 56 (2004).

[5] Yong-Ji Yu, Xin-Yu Chen, Chao Wang, Chun-Ting Wu, Miao Yu and Guang-Yong Jin, Optics Communications 304, 39 (2013).

[6] C. Czeranowsky, M. Schmidt, E. Heumann, G. Huber, S. Kutovoi and Y. Zavartsev, Optics Communications 205, 361 (2002).

[7] P. A. Loiko, K. V. Yumashev, N. V. Kuleshov and A. A. Pavlyuk, Applied Physics B 102, 117 (2011).

[8] PENG Ji-ying and ZHENG Yi, Journal of Optoelectronics ·Laser 24, 415 (2013). (in Chinese)

[9] Julien Didierjean, Emilie Herault, Fran ois Balembois and Patrick Georges, Optics Express 16, 8995 (2008).

[10] Chen Y. F., Lan Y. P. and Wang S. C., Optics Letters 25, 1016 (2000).

[11] C. Pfistner, R. Weber, H. P. Weber, S. Merazzi and R. Gruber, IEEE Journal of Quantum Electronics 30, 1605 (1994).

[12] Sten Helmfrid and Kimio Tatsuno, Journal of Optical Society American B 11, 436 (1994).