Optical modulator

Abstract

Abstract PURPOSE:To obtain a high quenching ratio with a low driving voltage and to permit the increased tendency to the shorter wavelength and longer wavelength at an absorption end by changing the forbidden band width of a semiconductor layer having the narrow forbidden band width in a semiconductor film monotonously in the lamination direction. CONSTITUTION:Multi-layered structure is formed by laminating a GaAs buffer layer 32 and an Al0.4Ga0.6As clad layer 33 on a GaAs substrate 31, alternately laminating AlxGa1-xAs quantum well layers 34 in which the A compsn. ratio (x) is continuously changed from 0 to 0.15 and Al0.4Ga0.6As barrier layers 35 to 30 periods and growing a Be-doped p-type Al0.4 Ga0.6As clad layer 36 and a GaAs contact layer 37 thereon. The GaAs layers on the top and bottom surfaces are selectively etched and are circularly removed. Electrodes 38 are formed on the GaAs layers except the same. The electrode on the n side is grounded while the origin at the (x) axis slightly moves to the left side. The absorption end has the longer wavelength when a negative voltage is impressed to the electrode on the p side. Said end has the shorter wavelength when the voltage in the reverse direction is impressed thereto. The high quenching ratio is thus obtd. with the low voltage and the increased tendency toward the shorter wavelength and longer wavelength at the absorption end and the high-speed modulation are made possible by changing the impressing direction of the voltage.

Inventors

• 👤 Kenichi Nishi
• 👤 研一 西
• 👤 Hiroyoshi Rangu
• 👤 博義 覧具

Bibliographic Details