Second-harmonic generation (SHG) has been observed in optically poled TeO
2-WO
3 glasses doped with vanadium. The second-harmonic (SH) intensity depends on the concentration of vanadium; the glass doped with 0.1 mol% of V
2O
5 manifests the maximum SH intensity. The SH intensity is larger and the second-order nonlinearity is more stabile for 20WO
3 · 80TeO
2 glasses than for 15Nb
2O
5 · 85TeO
2 glasses reported previously. Besides, enhancement of SH intensity is observed in glasses co-doped with rare-earth element such as Tb, Pr, and Ce in addition to vanadium. We speculate that Tb
4+, Pr
4+and Ce
4+ play a role of trap centers for electrons; a positive hole trapped at V
4+ as well as the electron trapped at the tetravalent rare-earth ion forms internal dc field, the spatial periodic variation of which gives rise to SHG.
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