7 July 1998 AlGaN/GaN intersubband transitions for Tb/s 1.55-μm optical switches
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The feasibility of the inter-subband transition (ISBT) in Al(Ga)N/GaN quantum wells (QWs) as a device mechanism for ultrafast optical switches is theoretically investigated. The 1.55-micrometers ISBT is shown to be feasible because of its large conduction band discontinuity. The inter-subband relaxation time at 1.55 micrometers is estimated to be about 100 fs, which is 20 - 30 times shorter than that in InGaAs QWs. A large electron-electron scattering rate causes a short dephasing time (about 10 fs), which reduces the peak value of the third-order nonlinear susceptibility. At a high carrier density, however, the dephasing time is increased because of the screening and the exclusion, which enhances the nonlinear susceptibility. Ultrafast relaxation of the inter-subband optical nonlinearity in GaN QWs is little affected by the delay in intra-subband energy relaxation caused by non-equilibrium phonons. These characteristics suggest that the ISBT in nitride QWs is a promising mechanism for multi-terabit/s optical switches.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Nobuo Suzuki, Nobuo Suzuki, Norio Iizuka, Norio Iizuka, "AlGaN/GaN intersubband transitions for Tb/s 1.55-μm optical switches", Proc. SPIE 3283, Physics and Simulation of Optoelectronic Devices VI, (7 July 1998); doi: 10.1117/12.316712; https://doi.org/10.1117/12.316712

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