摘要 |
A waveguide becomes a single mode waveguide under the condition as described below. If the LiNbO3 waveguide includes an Na content in a range of 0.1 to 14.3 mol % and an Mg content in a range of 0.8 to 10.8 mol %, and provided that T((my)m) represents a thickness of the waveguide, and (lambda) ((my)m) represents a wavelength of the guided wave, then the relationships in the following equations are preferable, in the case of TM mode, 1.9<(T+0.7)/(lambda)<5.7 (T>0) in the case of TE mode, 0.29<(T+0.04)/(lambda)<1.19 (T>0). |