[2] [2] Qihong Lou, Jun Zhou, Jianqiang Zhu et al.. 50-watt ytterbium-doped double-clad fiber laser. Chin. Opt. Lett., 2003, 1(10): 559～560

[4] [4] Taverner D, Britton P, Smith P G R et al.. Highly efficient second-harmonic and sum-freuency generation of nanosecond pulse in a cascaded erbium-doped fiber: periodically poled lithium niobate source. Opt. Lett., 1998, 23(3): 162～164

[6] [6] Jundt D N. Temperature-dependent Sellmeier equation for the index of refraction, ne, in congruent Lithium niobate. Opt. Lett., 1997, 22(20): 1553～1555

[7] [7] Edwards G J, Lawrence M. A temperature-dependent dispersion equation for congruently grown Lithium niobate. Opt. Quant. Electron., 1984, 16(4): 373～374

[9] [9] Guskov S A, Popov S, Chernikov S V et al.. Second harmonic generation around 0.53 μm of seeded Yb fibre system in periodically poled lithium niobate. Electron. Lett., 1998, 34(34): 1419～1420

[10] [10] Champert P A, Popov S V, Taylor J R. Highly, variable pulse format 770 nm sourse based on powerful seeded generation in periodically poled KTP. Electron. Lett., 2000, 36(7): 648～649