| 摘要 |
PROBLEM TO BE SOLVED: To suppress the propagation loss of signal light in a light control element by forming a distortion clad layer, into which a (p) type impurity is led, having tension distortion on a light absorbing layer, which is formed on a lower clad layer, having a multiple quantum well layer. SOLUTION: As for a modulation part 113 of an optical waveguide 110, a light absorbing layer 130 in multiple quantum well structure is formed by laminating a lower clad layer 120 composed of n-InP, barrier layer composed of InAlAs and well layer composed of InGaAs on a substrate 100. Then, the P-type impurity is introduced on that layer 130, a distortion clad layer 140 composed of InGaAsP adding the tension distortion is formed, and an upper clad layer 150 composed of the P-type InP is formed. By loading an electric field to the modulation part 113, the refraction factor of light propagated on the light absorbing layer 130 is changed and the phase is changed. The propagation loss of TE polarized light exposed over the distortion clad layer 140, to which the tension distortion is introduced, can be suppressed. |
