Grant-in-Aid for Scientific Research (A).
|Research Institution||Tokyo Institute of Technology|
TSUJI Shigeo Tokyo Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (50020350)
ASADA Masahiro Tokyo Institute of Technology, Faculty of Engineering, Associate Professor, 工学部, 助教授 (30167887)
SAKANIWA Koichi Tokyo Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (30114870)
FURUYA Kazuhito Tokyo Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (40092572)
IGA Kenichi Tokyo Institute of Technology, Precision and Intelligence Laboratory, Professor, 精密工学研究所, 教授 (10016785)
HIROTA Osamu Tamagawa University, Faculty of Engineering, Professor, 工学部, 教授 (40114889)
|Project Fiscal Year
1991 – 1993
Completed(Fiscal Year 1993)
|Budget Amount *help
¥29,100,000 (Direct Cost : ¥29,100,000)
Fiscal Year 1993 : ¥3,000,000 (Direct Cost : ¥3,000,000)
Fiscal Year 1992 : ¥7,700,000 (Direct Cost : ¥7,700,000)
Fiscal Year 1991 : ¥18,400,000 (Direct Cost : ¥18,400,000)
|Keywords||Quantum State Control / Optical Communication System / Quantum Communication Theory / Received Quantum State Control / Conditional Unitary / Squeezed Light / 量子状態制御 / 光通信システム / 量子通信理論 / 受信量子状態制御 / 条件付ユニタリ / スクィズド光 / 量子光通信 / スクイズド光 / 条件付きユニタリ-過程 / 非線形光学現象 / 光注入同期|
Research results achieved in the current year are summarized as follows :
1.Designing a cavity-type squeezed light generator.
A cavity-type squeezed-light generator in which a nonlinear optical device (KTP) made in the last year is placed was produced in order to heighten efficiency of optical second harmonic generation (SHG) by means of the KTP.In this system, since the fundamental mode field is in a squeezed state different from ordinary SHG experiments, lenses of the confocal resonator were optimally designed, so that it was confirmed that the fundamental mode field can be taken out sufficiently, and that the efficiency is expected to be 60%.
2.Establishing a new method for designing optical nonlinear devices.
Large degree of nonlinearity is required for generation of squeezed light. It was found that the imaginary part of the nonlinear susceptibility of an optical nonlinear device, which has never been taken into consideration, plays important role in the generation process. Furthermor
e, the relation between the imaginary part and squeezing phenomenon was clarified and optimization of designing optical nonlinear devices for squeezed light generation was performed taking the imaginary part into consideration.
3.Development of basic theory for quantum communication.
Basic theory for quantum state control method including squeezed light was developed in order to verify theoretically that the quantum communication is superior to the conventional optical communication. Especially, new fundamental properties of quantum fluctuations were clarified and a new mathematical method was exploited to describe them. Based on this, a new quantum state control method by means of the combination of an optical Kerr-effect and a squeezer was proposed, and its properties, such as error performance and signal-to-noise ratio, were numerically studied.
4, Improvement of squeezed-light detection system.
Interference efficiency of self-homodyne detection system made in the last year was heightened up to 85%. Then, the basic experiment of the self-homodyne detection system was finished. Since then, an experiment of a balanced-homodyne detection system has been done to confirm the cancellation of shot noise of signal field. Less