| 摘要 |
PROBLEM TO BE SOLVED: To provide an n-SI-n-type heterostructure semiconductor optical modulation element capable of reducing electrical and optical loss of a semiconductor and allowing high-speed optical modulation.SOLUTION: In order to achieve high speed optical modulation by reducing electrical and optical loss and a high quality optical modulation signal, an optical modulation region includes an n-SI-n-type heterostructure formed by sandwiching with n-type cladding layers a semi-insulating (SI) core layer having an electron density and the density of an electron trapping dopant set so that a voltage drop is efficiently generated near the centre of the SI core layer, in a range where an ohmic value of 1×10&OHgr; cm or more is secured. This structure confines propagation light near the centre of the SI layer. |
