A V-shaped module technique for promoting generation photocurrent density of silicon solar cells

A V-shaped solar cell module consists of two tilted mono-crystalline cells [J. Li, China Patent No. 200410007708.6 (March, 2004)]. The angle included between the two tilted cells is 90 degrees. The two cells were fabricated by using polished silicon wafers. The scheme of both-side polished wafers has been proposed to reduce optical loss. Compared to solar cells in a planar way, the V-shaped structure enhances external quantum efficiency and leads to an increase of 15% in generation photocurrent density. The following three kinds of trapped photons are suggested to contribute to the increase: (1) infrared photons converted from visible photons due to a transformation mechanism, (2) photons reflected from top contact metal, and (3) a residual reflection which can not be eliminated by an antireflection coating.

Impact of diode facet reflectivity on the fiber grating external cavity semiconductor laser

The scattering matrix method is used to analyze the multiple reflection effect between the laser diode facet and the fiber grating facet by considering the fiber grating external cavity laser diode (FGECL) as a four-mirror cavity laser. When neglecting other important parameters such as butt-coupling distance between the diode and the fiber facets, coupling efficiency, external cavity length, it is shown that low reflectivity is not a crucial factor for the laser characteristics such as SMSR. Experimentally high SMSR fiber grating external cavity laser is fabricated with a relatively large residual facet reflectivity (about 1%), which is coincident with our simulation results.

A simple method to realize large-bandwidth and high-efficiency wavelength conversion in Si waveguide

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T07:06:36Z No. of bitstreams: 1 A simple method to realize large-bandwidth and high-efficiency wavelength conversion in Si waveguide.pdf: 277035 bytes, checksum: ca7e272b2286b305d385825417857f21 (MD5)

Reconfigurable Optical Add-Drop Multiplexer Based on Silicon Photonic Wire Waveguide

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T07:40:23Z No. of bitstreams: 1 Reconfigurable Optical Add-Drop Multiplexer Based on Silicon Photonic Wire Waveguide.pdf: 416355 bytes, checksum: 5b80992194ba9fa818a011244cec6363 (MD5)

Diffractive Grating Based Out-of-Plane Coupling between Silicon Nanowire and Optical Fiber

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T07:55:26Z No. of bitstreams: 1 Diffractive Grating Based Out-of-Plane Coupling between Silicon Nanowire and Optical Fiber.pdf: 232805 bytes, checksum: 0bd17756b8a703bf8337dd25bbddaca3 (MD5)

Design and Simulation Analysis of Spot-Size Converter in Silicon-On-Insulator

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:02:20Z No. of bitstreams: 1 Design and Simulation Analysis of Spot-Size Converter in Silicon-On-Insulator.pdf: 239163 bytes, checksum: 82db1386c266d0c07442a972348da08c (MD5)

High-Order Microring Filters on SOI Wafer

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:05:17Z No. of bitstreams: 1 High-Order Microring Filters on SOI Wafer.pdf: 236326 bytes, checksum: dea85274da2a205a54b8a46049db9c94 (MD5)

High-Q and High-extinction-ratio Microdisk Add-drop Filter with Grating Couplers in Silicon-on-Insulator

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:08:51Z No. of bitstreams: 1 High-Q and High-extinction-ratio Microdisk Add-drop Filter with Grating Couplers in Silicon-on-Insulator.pdf: 662474 bytes, checksum: dbdd3fba410c875bd74a6d4823930a44 (MD5)

InGaAsP/InP Bistability Triangle Microlasers

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:12:07Z No. of bitstreams: 1 InGaAsP-InP Bistability Triangle Microlasers.pdf: 305729 bytes, checksum: 9bfb7f71e2d39dc99bcee91b9a48de3c (MD5)

Large-Signal Performance of 1.3 mu m InAs/GaAs quantum-dot lasers

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:15:32Z No. of bitstreams: 1 Large-Signal Performance of 1.3 mu m InAs-GaAs quantum-dot lasers.pdf: 281494 bytes, checksum: 1ebcdfdc887e3a3b279e07b3f655167b (MD5)

Demonstration of high efficient tunable lasing with one photonic crystal W1 waveguide

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:18:15Z No. of bitstreams: 1 Demonstration of high efficient tunable lasing with one photonic crystal W1 waveguide.pdf: 564778 bytes, checksum: 1eb1246461d4a3fcc99e870bda90f9b4 (MD5)

Numerical simulations of interrupted and conventional microchannel heat sinks

We provide three-dimensional numerical simulations of conjugate heat transfer in conventional and the newly proposed interrupted microchannel heat sinks. The new microchannel heat sink consists of a set of separated zones adjoining shortened parallel microchannels and transverse microchambers. Multi-channel effect, physical property variations, and axial thermal conduction are considered. It is found that flow rate variations in different channels can be neglected, while heat received by different channels accounts for 2% deviations from the averaged value when the heat flux at the back surface of the silicon chip reaches 100 W/cm(2). The computed hydraulic and thermal boundary layers are redeveloping in each separated zone due to shortened flow length for the interrupted microchannel heat sink. The periodic thermal developing flow is responsible for the significant heat transfer enhancement. Two effects influence pressure drops across the newly proposed microchannel heat sink. The first one is the pressure recovery effect in the microchamber, while the second one is the head loss when liquid leaves the microchamber and enters the next zone. The first effect compensates or suppresses the second one, leading to similar or decreased pressure drop than that for the conventional microchannel heat sink, with the fluid Prandtl number larger than unity.

Superluminal radio source PKS 0420-014

The very long baseline interferometry result of a superluminal radio source PKS 0420-014 at 5 GHz with Shanghai (China), Urumqi (China), Note (Italy), and HartRAO (South Africa) telescopes is presented. Proper motions of the relativistic jet components in the source are calculated. Based on the Self-Compton emission in a uniform spherical model, the beaming parameters of the source are estimated. The results show that PKS 0420-014 has a high Doppler factor of 9.3, a Lorentz factor of 6.5, and a small angle of 5.5 degrees to the line of sight.