中国物理B ›› 2005, Vol. 14 ›› Issue (4): 812-817.doi: 10.1088/1009-1963/14/4/030

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Enhancement of absorptive optical nonlinearity of asymmetrically coupled quantum well structures

黄德修1, 胡振华2   

  1. (1)Department of Optoelectronics Engineering, Huazhong University of Science and Technology, Wuhan,430074, China; (2)Department of Optoelectronics Engineering, Huazhong University of Science and Technology, Wuhan,430074, China;Department of Physics, Wuhan University of Technology,Wuhan, 430063, China
  • 收稿日期:2004-07-12 修回日期:2004-12-08 出版日期:2005-04-20 发布日期:2005-03-28
  • 基金资助:
    Project supported by the State Key Development Programme for Basic Research of China (Grant No G20003605)

Enhancement of absorptive optical nonlinearity of asymmetrically coupled quantum well structures

Hu Zhen-Hua (胡振华)ab, Huang De-Xiu (黄德修)a   

  1. a Department of Optoelectronics Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; b Department of Physics, Wuhan University of Technology, Wuhan 430063, China
  • Received:2004-07-12 Revised:2004-12-08 Online:2005-04-20 Published:2005-03-28
  • Supported by:
    Project supported by the State Key Development Programme for Basic Research of China (Grant No G20003605)

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摘要： The third-order nonlinear susceptibility $\chi ^{({3})}$ of asymmetrically coupled quantum well (ACQW) structure is calculated by employing a V-type three-level model. The efficiency of absorptive optical nonlinearity, which we define as the ratio of the third-order nonlinear susceptibility $\chi ^{({3})}$ to the linear absorptive coefficient $\alpha_0$, is analysed for different electronic coherence oscillation frequencies. We show that the efficiency is enhanced with the increase of the electronic coherence oscillation frequency between the two wells but is degenerated as that of a single quantum well when the electronic coherence oscillation frequency is zero. Compared with single quantum well, the ACQW designed has the property of nonlinear absorption and dispersion depending strongly on the external electric field along the growth direction. We predict that ACQW structures can provide both high efficiency limiters and controllable optical Kerr switch in future communication systems.

Abstract: The third-order nonlinear susceptibility $\chi ^{({3})}$ of asymmetrically coupled quantum well (ACQW) structure is calculated by employing a V-type three-level model. The efficiency of absorptive optical nonlinearity, which we define as the ratio of the third-order nonlinear susceptibility $\chi ^{({3})}$ to the linear absorptive coefficient $\alpha_0$, is analysed for different electronic coherence oscillation frequencies. We show that the efficiency is enhanced with the increase of the electronic coherence oscillation frequency between the two wells but is degenerated as that of a single quantum well when the electronic coherence oscillation frequency is zero. Compared with single quantum well, the ACQW designed has the property of nonlinear absorption and dispersion depending strongly on the external electric field along the growth direction. We predict that ACQW structures can provide both high efficiency limiters and controllable optical Kerr switch in future communication systems.

Key words: asymmetrically coupled quantum well structures, third-order nonlinearity, effect of absorptive optical nonlinearity

中图分类号:  (Optical susceptibility, hyperpolarizability)

  • 42.65.An
42.65.Hw (Phase conjugation; photorefractive and Kerr effects) 78.20.Ci (Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)) 78.67.De (Quantum wells)