| Project/Area Number |
11450023
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied optics/Quantum optical engineering
|
|---|
| Research Institution | Yamagata University |
|---|
Principal Investigator |
KAWAGUCHI Hitoshi Yamagata University, Faculty of Enginnering, Professor, 工学部, 教授 (40211180)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Yutaka Yamagata University, Faculty of Enginnering, Associate Professor, 工学部, 助教授 (00260456)
川添 忠 山形大学, 工学部, 助手 (50291282)
|
|---|
| Project Period (FY) |
1999 – 2001
|
| Project Status |
Completed (Fiscal Year 2001)
|
| Budget Amount *help |
¥14,800,000 (Direct Cost: ¥14,800,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 1999: ¥8,400,000 (Direct Cost: ¥8,400,000)
|
|---|
| Keywords | Semiconductor laser / Optical bistability / Vertical-cavity surface-emitting laser / Polarization switching / All-optical signal processing / Quantum well / Spin relaxation / Spin injection / 半導体レーザ / 面発光半導体レーザ / 3R中継 / 歪量子井戸 / スピン偏極電子 / RZ / NRZ変換 / 全光型多重分離 / 光DEMUX |
|---|
| Research Abstract |
We investigated mainly the following four topics to create new nonlinear optical functional devices based on the pitchfork bifurcation bistable operation of vertical-cavity surface-emitting lasers (VCSELs) and injection of spin-polarized electrons.
(1) We studied the bistable switching between the two orthogonal polarization mode existing in the VCSEL with a squared shape waveguide. The relative magnitude of self- and cross-saturation coefficients are crucial to determine the characteristics of polarization switching of laser diodes. The numerical calculation confirmed that the relation between self- and cross saturation coefficients satisfies the condition for polarization bistability in both balk and quantum well active layers. The bistable conduction is satisfied in the wider region for a compressively strained quantum well, especially in the region with large linear gains.
(2) All-optical signal processing, such as demultiplexing with a signal bit width conversion function and the conversion between RZ and NRZ formats, were experimentally demonstrated using a polarization bistable VCSEL. We have shown by our simulations that the 3R function (Retiming, Reshaping, and Regenerating) can be obtained using a such VCSEL.
(3) We estimated the spin relaxation time of the electrons drifting through the p-n junction from the time- and polarization- resolved photoluminescence. The result showed that the polarization fairly maintained during the drift.
(4) We fabricated the light emitting diode (LED) with an n-side electrode made of ferromagnetic metal, CoCr. However, the light output from LED was unpolarized. This result points out that the polarized electrons may be de-polarized at the interface between GaAs and CoCr.
|
