| 摘要 |
PURPOSE:To realize small-size and monolithic integration and to reduce variation in loss due to the switching of light by providing a means which applies an electric field in parallel to respective layers of a quantum well and a means which applies an electric field at right angles to a quantum well nearby said quantum well. CONSTITUTION:A voltage is applied between two Schottky electrodes 1a and 1b. In this case, an electric field parallel to a multiple quantum sell MQW guide layer 7 is applied between the electrodes 1a and 1b and the disappearance of an exciton absorption peak due to the ionization of an exciton is caused to induce variation in refractive index. At the same time, when a voltage is so applied as to hold an ohmic electrode 3 at the same potential with the electrode 1a and Schottky electrodes 2a and 2b at the same potential with the electrode 1b, an electric field at right angles to the MQW guide layer 7 is applied between the electrodes 2a and 2b, and 3 to cause positive refractive index variation on the long-wavelength side of the exciton absorption peak. Their variation areas are areas 9a and 9b and a part whose refractive index is relatively lower than those of its surrounding layers 9a and 9b is formed at the part 10, so that relatively large variation in refractive index is obtained. Consequently, the switch is reduced in size. |
