|
| Record 1 of 9 |
| Author(s): Li, ZY (Li, Zhi-Yong); Xu, DX (Xu, Dan-Xia); McKinnon, WR (McKinnon, W. Ross); Janz, S (Janz, Siegfried); Schmid, JH (Schmid, Jens H.); Cheben, P (Cheben, Pavel); Yu, JZ (Yu, Jin-Zhong) |
| Title: Silicon waveguide modulator based on carrier depletion in periodically interleaved PN junctions |
| Source: OPTICS EXPRESS, 17 (18): 15947-15958 AUG 31 2009 |
| Abstract: We present the design and numerical simulation results for a silicon waveguide modulator based on carrier depletion in a linear array of periodically interleaved PN junctions that are oriented perpendicular to the light propagation direction. In this geometry the overlap of the optical waveguide mode with the depletion region is much larger than in designs using a single PN junction aligned parallel to the waveguide propagation direction. Simulations predict that an optimized modulator will have a high modulation efficiency of 0.56 V.cm for a 3V bias, with a 3 dB frequency bandwidth of over 40 GHz. This device has a length of 1.86 mm with a maximum intrinsic loss of 4.3 dB at 0V bias, due to free carrier absorption. (C) 2009 Optical Society of America |
| ISSN: 1094-4087 |
| Record 2 of 9 |
| Author(s): Chen, W (Chen, Wei); Zhu, NH (Zhu, Ning Hua); Man, JW (Man, Jiang Wei); Xiong, S (Xiong, Shang); Xie, L (Xie, Liang) |
| Title: DISCRETELY TUNABLE FIBER RING LASER USING FBG TUNABLE FILTER AND MACH-ZEHNDER INTERFEROMETER |
| Source: MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 51 (11): 2595-2598 NOV 2009 |
| Abstract: A discretely tunable Er-doped fiber-ring laser using a fiber Mach-Zehnder interferometer (MZI) and a tunable fiber Bragg grating (FBG) is proposed. In this scheme, the combination of MZI and FBG acts as a discrete wavelength selector. Analysis of its transmission function shows that discrete wavelength tuning can be realized, and experiments demonstrate 64 single-mode outputs with a mode spacing of 181.7 pm, and the output power is quite stable in the whole tuning range. (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2595-2598, 2009; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.24690 |
| ISSN: 0895-2477 |
| DOI: 10.1002/mop.24690 |
| Record 3 of 9 |
| Author(s): Li, H (Li, Hui); Wang, Z (Wang, Zhu); Zhou, K (Zhou, Kai); Pang, JB (Pang, Jingbiao); Ke, JY (Ke, Junyu); Zhao, YW (Zhao, Youwen) |
| Title: Proton irradiation-induced defects in undoped GaSb studied by positron lifetime spectroscopy and photoluminescence |
| Source: JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, 11 (8): 1122-1126 AUG 2009 |
| Abstract: Undoped GaSb was irradiated by 2.6 MeV protons. The irradiation-induced defects were studied by positron lifetime spectroscopy (PLS) and photoluminescence (PL). Positron lifetime measurements showed that vacancy-type defects were introduced after irradiation, and divacancies were formed at higher irradiation dose. Annealing experiments revealed there were different annealing steps between the as grown and proton-irradiated samples, the reason for which was tentatively attributed to the formation of divacancies in the proton-irradiated samples during annealing. All the vacancy defects could be annealed out at around 500 degrees C. The PL intensity quickly fell down after proton irradiation and decreased with increasing irradiation dose, indicating that irradiation induced non-irradiative recombination centers, whose candidates were assigned to the vacancy defects induced by proton irradiation. |
| ISSN: 1454-4164 |
| Record 4 of 9 |
| Author(s): Chen, J (Chen, J.); Fan, WJ (Fan, W. J.); Xu, Q (Xu, Q.); Zhang, XW (Zhang, X. W.); Li, SS (Li, S. S.); Xia, JB (Xia, J. B.) |
| Title: Electronic structure and optical gain of truncated InAs1-xNx/GaAs quantum dots |
| Source: SUPERLATTICES AND MICROSTRUCTURES, 46 (3): 498-506 SEP 2009 |
| Abstract: The shape of truncated square-based pyramid quantum dots (QDs) is similar to that of real QDs in experiments. The electronic band structures and optical gain of InAs1-xNx/GaAs QDs are calculated by using the 10-band k.p model, and the strain is calculated by the valence force field (VFF) method. When the top part of the QD is truncated, greater truncation corresponds to a flatter shape of the QD. The truncation changes the strain distribution and the confinement in the z direction. A flatter QD has a greater C1-HH1 transition energy, greater transition matrix element, less detrimental effect of higher excited transition, and higher saturation gain and differential gain. The trade-off between these properties must be considered. From our results, a truncated QD with half of its top part removed has better overall performance. This can provide guidance to growing QDs in experiments in which the proper growing conditions can be controlled to achieve required properties. (C) 2009 Elsevier Ltd. All rights reserved. |
| ISSN: 0749-6036 |
| DOI: 10.1016/j.spmi.2009.05.002 |
| Record 5 of 9 |
| Author(s): Guo, J (Guo, Jie); Peng, ZY (Peng, Zhenyu); Sun, WG (Sun, Weiguo); Xu, YQ (Xu, Yingqiang); Zhou, ZQ (Zhou, Zhiqiang); Niu, ZC (Niu, Zhichuan) |
| Title: InAs/GaSb superlattices for photodetection in short wavelength infrared range |
| Source: INFRARED PHYSICS & TECHNOLOGY, 52 (4): 124-126 JUL 2009 |
| Abstract: The first report of a short wavelength infrared detector based on type II InAs/GaSb superlattices is presented. Very short period superlattices containing InAs (2ML)/GaSb (8ML) superlattices (SLs) were grown by molecular-beam epitaxy on GaSb substrates. The photoluminescence showed a cut-off wavelength at 2.1 mu m at 10 K and 2.6 mu m at 300 K. Room-temperature optical transmittance spectra shows obvious absorption in InAs (2ML)/GaSb (8ML) SL in the range of 450-680 meV, i.e. 1.8-2.7 mu m. The cut-off wavelength moved from 2.3 mu m to 2.6 mu m with temperature rising from 77 K to 300 K in photoresponse spectra. The blackbody response R-v exponentially decreased as a function of 1/T in two temperature sections (130-200 K and 230-300 K). The blackbody detectivity D-bb(center dot) was beyond 1 x 10(8) cmHz(1/2)/W at room temperature. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 1350-4495 |
| DOI: 10.1016/j.infrared.2009.04.003 |
| Record 6 of 9 |
| Author(s): Hu, Q (Hu Qiang); Wei, TB (Wei Tong-Bo); Duan, RF (Duan Rui-Fei); Yang, JK (Yang Jian-Kun); Huo, ZQ (Huo Zi-Qiang); Lu, TC (Lu Tie-Cheng); Zeng, YP (Zeng Yi-Ping) |
| Title: Characterization of Thick GaN Films Directly Grown on Wet-Etching Patterned Sapphire by HVPE |
| Source: CHINESE PHYSICS LETTERS, 26 (9): Art. No. 096801 SEP 2009 |
| Abstract: Thick GaN films of high quality are directly grown on wet-etching patterned sapphire in a vertical hydride vapour phase epitaxy reactor. The optical and structural properties of GaN films are studied using scanning electronic microscopy and cathodoluminescence. Test results show that initial growth of hydride vapour phase epitaxy GaN occurs not only on the mesas but also on the two asymmetric sidewalls of the V-shaped grooves without selectivity. After the two-step coalescence near the interface, the GaN films near the surface keep on growing along the direction perpendicular to the long sidewall. Based on Raman results, GaN of the coalescence region in the grooves has the maximum residual stress and poor crystalline quality over the whole GaN film, and the coalescence process can release the stress. Therefore, stress-free thick GaN films are prepared with smooth and crack-free surfaces by this particular growth mode on wet-etching patterned sapphire substrates. |
| ISSN: 0256-307X |
| Article Number: 096801 |
| Record 7 of 9 |
| Author(s): Xu, XJ (Xu Xue-Jun); Chen, SW (Chen Shao-Wu); Xu, HH (Xu Hai-Hua); Sun, Y (Sun Yang); Yu, YD (Yu Yu-De); Yu, JZ (Yu Jin-Zhong); Wang, QM (Wang Qi-Ming) |
| Title: High-speed 2 x 2 silicon-based electro-optic switch with nanosecond switch time |
| Source: CHINESE PHYSICS B, 18 (9): 3900-3904 SEP 2009 |
| Abstract: A 2 x 2 electro-optic switch is experimentally demonstrated using the optical structure of a Mach-Zehnder interferometer (MZI) based on a submicron rib waveguide and the electrical structure of a PIN diode on silicon-on-insulator (SOI). The switch behaviour is achieved through the plasma dispersion effect of silicon. The device has a modulation arm of I mm in length and cross-section of 400 nmx340 nm. The measurement results show that the switch has a V pi L pi figure of merit of 0.145 V-cm and the extinction ratios of two output ports and cross talk are 40 dB, 28 dB and -28 dB, respectively. A 3 dB modulation bandwidth of 90 MHz and a switch time of 6.8 ns for the rise edge and 2.7 ns for the fall edge are also demonstrated. |
| ISSN: 1674-1056 |
| Record 8 of 9 |
| Author(s): Zhao, JZ (Zhao Jian-Zhi); Lin, ZJ (Lin Zhao-Jun); Corrigan, TD (Corrigan, Timothy D.); Zhang, Y (Zhang Yu); Lu, YJ (Lue Yuan-Jie); Lu, W (Lu Wu); Wang, ZG (Wang Zhan-Guo); Chen, H (Chen Hong) |
| Title: Determination of the relative permittivity of the AlGaN barrier layer in strained AlGaN/GaN heterostructures |
| Source: CHINESE PHYSICS B, 18 (9): 3980-3984 SEP 2009 |
| Abstract: Using the measured capacitance-voltage curves and the photocurrent spectrum obtained from the Ni Schottky contact on a strained Al0.3Ga0.7N/GaN heterostructure, the value of the relative permittivity of the AlGaN barrier layer was analysed and calculated by self-consistently solving Schrodinger's and Poisson's equations. It is shown that the calculated values of the relative permittivity are different from those formerly reported, and reverse biasing the Ni Schottky contact has an influence on the value of the relative permittivity. As the reverse bias increases from 0 V to - 3 V, the value of the relative permittivity decreases from 7.184 to 7.093. |
| ISSN: 1674-1056 |
| Record 9 of 9 |
| Author(s): Hu, WX (Hu, Weixuan); Cheng, BW (Cheng, Buwen); Xue, CL (Xue, Chunlai); Xue, HY (Xue, Haiyun); Su, SJ (Su, Shaojian); Bai, AQ (Bai, Anqi); Luo, LP (Luo, Liping); Yu, YD (Yu, Yude); Wang, QM (Wang, Qiming) |
| Title: Electroluminescence from Ge on Si substrate at room temperature |
| Source: APPLIED PHYSICS LETTERS, 95 (9): Art. No. 092102 AUG 31 2009 |
| Abstract: A Ge/Si heterojunction light emitting diode with a p(+)-Ge/i-Ge/N+-Si structure was fabricated using the ultrahigh vacuum chemical vapor deposition technology on N+-Si substrate. The device had a good I-V rectifying behavior. Under forward bias voltage ranging from 1.1 to 2.5 V, electroluminescence around 1565 nm was observed at room temperature. The mechanism of the light emission is discussed by the radiative lifetime and the scattering rate. The results indicate that germanium is a potential candidate for silicon-based light source material. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3216577] |
| ISSN: 0003-6951 |
| Article Number: 092102 |
| DOI: 10.1063/1.3216577 |
|
