Investigation of an ultrafast all optical modulation device using three levels in a GaN/AlGaN quantum well

研究在 GaN/AlGaN 量子阱中使用三能级的超快全光调制器件

• 批准号: 11555014
• 负责人: NODA Susumu
• 金额: $ 8.64万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555014/
• 关键词: GaN; AlGaN Quantum dot; Intersubband transition; All-optical modulation; Ultra fast relaxation; Carrier dynamics; Intersubband relaxation time; Monte Carlo simulation; フェムト秒

(1) The purpose of this research project is to develop an ultrafast all-optical modulation device which can operate at a speed of T-bits/s. The points of the developments are (a) utilization of the all-optical modulation method which has been proposed and investigated by the representative researcher, and (b) utilization of GaN / AlGaN quantum wells which are expected to have an ultra fast population relaxation time of 100 fs.(2) At first, the growth condition of GaN / AlGaN quantum well was investigated to maximize the numbers of quantum wells. It was found that the generation of the crack in the growth layer due to the lattice mismatch can be avoided by introducing a GaN buffer layer in between the AlGaN barrier layers. Therefore a multiple-quantum-well with 200 well layers has been successfully grown, which showed a strong intersubband absorption peak of 30-40% at a wavelength of 4.5 μm.(3) Next, the intersubband population relaxation time, which determines the modulation speed of t … More he device, was measured by one-color pump-probe method. It was experimentally shown for the first time that the relaxation time is as short as 100-200 fs. The result indicated that the response time of the modulation device can be as short as 100 fs.(4) The measurement system for the all-optical modulation experiment has been developed, which utilizes a differential frequency mixing crystal to generate a mid-infrared pulse and a water cell to generate a white-light generation in the water cell. For the comparison and trial, the modulation characteristics of the device consist of conventional GaAs/AlGaAs quantum wells was measured. The deference of the carrier relaxation dynamics between the GaAs/AlGaAs quantum wells and GaN/AlGaN quantum wells was precisely investigated.(5) The shortening of the intersubband transition wavelength in a GaN/AlGaN quantum well was investigated for the purpose of practical applications. By changing the growth method from MOVPE to MBE, a transition wavelength shorter than 1.55fj.m has been obtained. This is a very encouraging result since we can utilize a small semiconductor laser for the source of the control (pump) light. Less

（1）本研究项目的目的是开发一种运行速度为T位/秒的超快全光调制器件。开发要点是（a）利用代表研究人员提出并研究的全光调制方法，以及（b）利用预计具有100 fs超快布居弛豫时间的GaN / AlGaN量子阱。（2）首先，研究了GaN / AlGaN量子阱的生长条件，以最大化量子阱的数量。研究发现，通过在AlGaN势垒层之间引入GaN缓冲层，可以避免由于晶格失配而在生长层中产生裂纹。因此，成功生长了200个阱层的多量子阱，在4.5 μm波长处表现出30-40%的强子带间吸收峰。(3)接下来，通过单色泵浦探针方法测量了决定器件调制速度的子带间布居弛豫时间。实验首次证明弛豫时间短至100-200 fs。结果表明，该调制装置的响应时间可短至100 fs。(4)研制了全光调制实验测量系统，利用差频混频晶体产生中红外脉冲，利用水池在水池中产生白光。为了进行比较和试验，测量了由传统GaAs/AlGaAs量子阱组成的器件的调制特性。精确研究了GaAs/AlGaAs量子阱和GaN/AlGaN量子阱载流子弛豫动力学的差异。(5)研究了GaN/AlGaN量子阱中子带间跃迁波长的缩短，以供实际应用。通过将生长方法从MOVPE改为MBE，获得了小于1.55fj.m的跃迁波长。这是一个非常令人鼓舞的结果，因为我们可以利用小型半导体激光器作为控制（泵浦）光源。较少的

项目成果

T.Asano,M.Tamura,S.Yoshizawa,K.Tomoda and S.Noda: "Femtosecond pump and probe measurement of all-optical modulation based on intersubband transition in n-doped quantum wells"Physica E: Low-dimensional Systems And Nanostructures. (in printing). (2000)

T.Asano、M.Tamura、S.Yoshizawa、K.Tomoda 和 S.Noda：“基于 n 掺杂量子阱中子带间跃迁的全光调制的飞秒泵浦和探针测量”Physica E：低维系统和

N, Iizuka, K. Kaneko and N. Suzuki, T. Asano, S Noda, and O. Wada: "Ultrafast Intersubband Relaxation (<150 fs) in AlGaN/GaN Multiple Quantum Wells"Applied Physics Letters. Vol.77,No.5. 648-650 (2000)

N、Iizuka、K. Kaneko 和 N. Suzuki、T. Asano、S Noda 和 O. Wada：“AlGaN/GaN 多量子阱中的超快子带间弛豫 (<150 fs)”应用物理快报。

T. Asano, S. Noda, N. lizuka, K. Kaneko and N. Suzuki, and O. Wada: "Ultrafast all optical modulation based on intersubband transition in semiconductor quantum wells"Optical and Quantum Electronics. Vol.33. 963-973 (2001)

T. Asano、S. Noda、N. lizuka、K. Kaneko 和 N. Suzuki 以及 O. Wada：“基于半导体量子阱子带间跃迁的超快全光调制”光学和量子电子学。

T.Asano,S.Noda,N.Iizuka,K.Kaneko and N.Suzuki,and O.Wada: "Ultrafast all optical modulation based on intersubband transition in semiconductor quantum wells"Optical and Quantum Electronics. (In printing). (2001)

T.Asano、S.Noda、N.Iizuka、K.Kaneko 和 N.Suzuki 以及 O.Wada：“基于半导体量子阱子带间跃迁的超快全光调制”光学和量子电子学。

T. Asano and S. Noda: "Intersubband-transitions in InGaAs/AlAs QWs on GaAs and application to ultrafast all-optical modulators"Physics and Simulation of Optoelectronic Devices VII, Proceedings of SPIE. Vol.3625. 222-230 (1999)

T. Asano 和 S. Noda：“GaAs 上 InGaAs/AlAs QW 的子带间跃迁及其在超快全光调制器中的应用”，光电器件物理与模拟 VII，SPIE 论文集。