Fiber Optic Coupling of CW Linear Laser Diode Array

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Fabrication and Characterization of Monolithically Fused Wavelength-Independent 1 × 4 Couplers

Abstract

A new method for the fabrication of a monolithic 1 × 4 single-mode fused coupler is described together with details of its performance in terms of coupling ratio, spectral response and polarization sensitivity. The fabricated device exhibits ultra-broadband performance with low polarization dependent loss. The coupling pattern exhibits identical coupling to all interacting fibers, enabling an easy control on fabrication parameters of the device.     

BPM Simulation and Comparison of 1 × 2 Directional Waveguide Coupling and Y-Junction Coupling Silicon-on-Insulator Optical Couplers

For developing large area opto-electronic silicon-on-insulator (SOI) devices, the optical coupler is a basic key device. In this article, the authors design and simulate 1 2 2 directional waveguide coupling and Y-branch coupling optical couplers based on Unibond SOI rib waveguides. The beam propagation method (BPM) is used for light propagation analysis. The simulation results and comparisons of the two kinds of optical couplers are reported. The S-bend waveguide for attaching to the two kinds of SOI optical coupler is also analyzed by BPM. We find that the directional coupler has lower power loss, but the Y-junction coupler is more wavelength insensitive with the same device size and splitting angle. The fabrication tolerance analysis shows Y-junction coupler has better fabrication characteristics.     

Silicon-on-Insulator-Based Broadband 1×3 Adiabatic Splitter with Simultaneous Tapering of Velocity and Coupling

We propose and experimentally demonstrate a broadband 1×3 adiabatic splitter based on the silicon-on-insulator technology,with simultaneous tapering of velocity and coupling.The designed structure becomes simulated transmission uniformity of three outputs better than 0.5 dB in a broadband of 250 nm,and a large simulated fabrication tolerance is obtained.A manufactured splitter whose parameters greatly diverge from the design acquires a measured result of the worst splitting ratio better than 1.5 dB as well as an excess loss lower than0.8 dB in a large wavelength range of 80 nm.A post-simulation based on the tested splitter obtains a result that meets the actual transmission well.     

Hybrid Integration of 1 × 12 Metal-Semiconductor-Metal Photodetector and Polyimide Waveguide Array

We report here a demonstration of hybrid integration of a 1 × 12 metal-semiconductor-metal (MSM) photodetector array and polyimide channel waveguides via 45° total-internal-reflection (TIR) micro-couplers. The two-layer polyimide waveguide array was constructed using Ultradel 9120D for the core and Ultradel 9020 for the lower cladding layer. The coupling loss and propagation loss of the waveguide are 0.2dB and 0.21 dB/cm, respectively. The cross talk of the adjacent channels is -32 dB. The MSM photodetector array was fabricated on a semi-insulated GaAs wafer. The photodetectors are integrated to operate in the conventional vertical illumination mode. We measured the external quantum-efficiency and 3 dB bandwidth of the integrated MSM photodetectors at 0.4 A/W and 2.648 GHz, respectively. The aggregate 3 dB bandwidth of the 12-channel integrated system is 32 GHz.     

Calculations of the 3-D neutronics for CH HCSB TBM with 3×3 sub-modules

Using three dimension MCNP code and FENDL2.0 data library, neutronics calculation for a HCSB (helium cooling solid breeder) TBM (test blanket module) with 3×3 sub-modules has been performed. Local tritium breeding ratio (TBR) of 0.907, total tritium generation rate of 0.0175g·d-1, peak power density of 9.27MW·m-3 and total power deposit of 0.422MW·m-3 are obtained under neutron wall loading of 0.78MW·m-2 and duty factor of 22%.     

Calculations of the 3-D neutronics for CH HCSB TBM with 3×3 sub-modules

Using three dimension MCNP code and FENDL2.0 data library, neutronics calculation for a HCSB (helium cooling solid breeder ) TBM ( test blanket module ) with 3×3 sub-modules has been performed. Local tritium breeding ratio (TBR) of 0.907, total tritium generation rate of 0.0175 g•d^-1, peak power density of 9.27MW•m^-3  and total power deposit of 0.422MW•m^-3 are obtained under neutron wall loading of 0.78MW•m^-2 and duty factor of 22%.     

PS-1 Optical Interconnection of 2N×2N Using N×N Holographic Lens Array

A method of N×N sub-array crisscross insertion has been put forward. N×N holographic lens array is used for realizing PS-1 optical interconnection of the 2N×2N element array. The condition for the sub-array interlacing was analyzed. The formula of the PS-1 imaging magnifying power and the imaging distance have been given for both parallel light illumination and divergent light illumination. The results indicated that the formula of the PS-1 imaging magnifying power and imaging distance realized by N×N sub-array crisscross insertion are identical with the results of the PS realized by 2×2 holographic lens array. The experiments prove correctness of the formula.     

X-Ray Radiation Characteristics of Nested-Wire Array Implosion in Sino-Russian Joint Z-pinch Experiments on Angara-5-1

We report and discuss the results of x-ray radiation measurements in the Sino-Russian joint Z-Pinch experiments on Angara-5-1 facility with a load current of 2.5-3.6MA. The measurements were conducted by using an x-ray power meter (XRPM) and a time-resolved one-dimensional x-ray imaging system developed in China Academy of Engineering Physics. The experimental results indicate that an x-ray power-platform prior to a main peak and a less intensive sub-peak after the main peak in the waveform exist for the nested-wire array implosions, and the radiation process is relatively faster than that in the case of the single array. Laser shadowgraph of the imploding plasma suggests that the prior power-platform is a result of the collision of the inner-outer plasma layers. The faster radiation process of nested array implosion can be explained by analysing the corresponding result of the time-resolved one-dimensional imaging system, which demonstrates a better axial imploding uniformity and synchronization. In comparison with x-ray diode, the XRPM yields a higher height of x-ray power-platform due to its fiat energy response. The sub-peak after the main peak is proposed to be a result of the later-time additional implosion of plasma.     

PS~(-1) Optical Interconnection of 2N×2N Using N×N Holographic Lens Array

ＰＳ（ＰｅｒｆｅｃｔＳｈｕｆｆｌｅ）ｏｐｔｉｃａｌｉｎｔｅｒｃｏｎｎｅｃｔｉｏｎｃａｎｃｏｍｐｏｓｅｄｖａｒｉｏｕｓｏｐｔｉｃａｌｉｎｔｅｒｃｏｎｎｅｃｔｉｏｎｎｅｔｗｏｒｋｓ,ｆｏｒｅｘａｍｐｌｅΩｎｅｔｗｏｒｋ．Ｈｏｗｅｖｅｒ,ｉｔｓｃｏｎｖｅｒ...     

Modal analysis of 1×3 reflective triangular gratings under normal incidence

Modal analysis of the 1×3 highly efficient reflective triangular grating operating in the 800 nm wavelength under normal incidence for TE polarization is presented in this Letter.The rigorous coupled wave analysis and simulated annealing algorithm are used to design this beam splitter.The reflective grating consists of a highly reflective mirror and a transmission grating on the top.The mechanism of the reflective triangular grating is clarified by the simplified modal method.Then,gratings are fabricated by direct laser writing lithography.     

UV Spectra of Some Derivatives of 1–3 Benzodioxole with Weakly Perturbating Substituents (-CH2X). Study of a Constant Component of Intensity

In a preceding work⁽¹⁾ we have studied the UV-Visible spectrum of pterocarpin, a natural product which is known, with many of its derivatives, for its antifungal properties.^(2–6) The molecule of pterocarpin contains the benzodioxole moiety (figure I) whose presence could be a factor favourable to such properties. Furthermore, some of the benzodioxole derivatives are known as popular drug of abuse (ecstasy).^(7–10) Among our studies on the benzodioxole derivatives substituted in para to one of the oxygen atoms, we present in that paper the results of our UV spectroscopic investigations. This work concerns molecules with substitutents weakly interacting with the π system (i.e. substituents whose type is-CH₂X), since the spectra of these molecules display a basic phenomenon which has never been observed.     

SU(2) ×U(1) Gauge theory of bosonic and fermionic fields inS 3 ×R space-time

The tetradic Lorentz-gauge invariant formulation of the SU(2) × U(1) theory in S³ × R space-time is presented and the general gauge covariant Dirac-Klein-Gordon-Maxwell-Yang-Mills equations are derived. A direct comparison of these equations to those of the SU(2) × U(1) gauge theory on Minkowskian background points out major differences effectively induced by the minimally coupling to S³ × R gravity.     

Orbifold compactifications with three families of Su(3) ×Su(2) ×U(1)n

We construct several N = 1 supersymmetric three-generation models with SU(3)×SU(2)×U(1)ⁿ gauge symmetry, obtained from orbifold compactification of the heterotic string in the presence of constant gauge-background fields. This Wilson-line mechanism also allows us to eliminate extra colour triplets which could mediate fast proton decay.     

Electrodynamic Characteristics of Solid Solutions Pb(Fe1 – xScx)2/3W1/3O3 in a Broad Spectral Range

Physics of the Solid State - The methods of broadband dielectric spectroscopy are used to study the effect of substitution of Fe3+ by Sc3+ in Pb(Fe1 – xScx)2/3W1/3O3 solid...     

STM study of Pd growth on TiO2(100)-(1 × 3)

STM has been used to study the initial growth of palladium on TiO₂(100)-(1 × 3). The results demonstrate that STM is capable of imaging individual atoms which form part of a supported metal cluster. The data were obtained from small (35Ådiameter by 8Åhigh) clusters at a dispersed-equivalent coverage of about 0.01 ML. At higher coverages the clusters coalesce.