| 摘要 |
PURPOSE: To obtain an optical control element which operates on a low voltage, has a broad band width, is low in insertion loss, has high performance and is small in size by specifying the thickness of well layers and introducing a specific tensile stress into these well layers. CONSTITUTION: A non-doped InP clad layer 2 is grown at 0.5μm, MQW optical waveguide layers 3 consisting of 20 layers of quantum well structures consisting of InGaAsP layers of a thickness of 11 to 14mn introduced with 0.3 to 0.5% tensile stress as the well layers and InP layers of a thickness of 5nm as barrier layers and a non-doped InP clad layer 4 at 1 to 2μm and an InGaAs cap layer 5 at 0.5μm by an org. metal vapor growth method, etc., on an insulatable InP substrate 1. Next, parts 6 added with a P type impurity and parts 7 added with an (n) type impurity are so formed that voltage can be impressed on the MQW layers 3 in parallel therewith from outside by growing the crystals added with the impurities in such a manner that the one electrical conductivity shape varies from the other across a width of 1 to 4μm within the plane perpendicular to the respective layers with an SiN film as a mask.
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