1997 Fiscal Year Final Research Report Summary
Bistable polarization in the visible/near-infrared semiconductor lasers by injection locking and their application to logic devices
| Project/Area Number |
07650057
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | Doshisha University |
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Principal Investigator |
OHTA Tatehisa Doshisha University, Department of Electronics, Professor, 工学部・電子工学科, 教授 (40066246)
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| Project Period (FY) |
1995 – 1997
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| Keywords | Visible LD / Infrared LD / Light injection locking / TE and TM modes / Mode hopping / Polarization switching / Bistable polarization / Optical logic device |
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| Research Abstract |
This study deals with the bistable polarization switching of semiconductor lasers whose normal and inverted output could be obtained simultaneously. This bistability is realized by utilizing a semiconductor laser with bistable mode-hopping characteristics (master laser) and injecting the TM polarization output of this laser into another semiconductor laser (slave laser) constantly biased to the oscillation threshold. It is proposed and confirmed by experiment using CSP-type semiconductor lasers oscillating a single mode at 830 nm that, by assuming these two lasers as one optical system, bistable polarization switching can be obtained between the injection current of the system and the output polarization system. First, as the principle of this polarization switching, the dependence of the injected light wavelength on amplification index of a semiconductor laser amplifier is explained. Then, the control of output polarization by TM wave injection and mode hopping of a laser is explained
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and the bistable characteristics of this optical system are discussed from experimental and simulation viwpoints based on these principles. The advantages of this bistable polarization switching are pointed out theoretically and experimentally, and the intensity difference of the ON/OFF output and the rotation direction of the bistable loop can be set according to the characteristics of the master and the slave lasers. The possibility of multislave connection is possible and an optical system that can control each gate function can be expected.
Moreover, the polarization characteristics of SAS-and VSIS-type semiconductor lasers injecting the TM wave are studied experimentally. The bistable polarization switching by mode-hopping was not found. Therefore the performance of the polarization switching in a semiconductor laser caused by injection locking depends on the waveguide structure. Bistable polarization switching mechanism in semiconductor lasers is discussed with the polarization switching in a 633 nm He-Ne laser with internal mirrors. Less
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