Yaw-Dong Wu

New all-optical logic gates based on the local nonlinear Mach-Zehnder interferometer

We propose new all-optical logic gates containing a local nonlinear Mach-Zehnder interferometer waveguide structure. The light-induced index changes in the Mach-Zehnder waveguide structure make the output signal beam propagate through different nonlinear output waveguides. Based on the output signal beam propagating property, various all-optical logic gates by using the local nonlinear Mach-Zehnder waveguide interferometer structure with two straight control waveguides have been proposed to perform XOR/NXOR, AND/NAND, and OR/NOR logic functions.

High-quality-factor filter based on a photonic crystal ring resonator for wavelength division multiplexing applications

We investigate the properties of ring resonators that are supported by a two-dimensional photonic crystal waveguide. The proposed structure composed of a photonic crystal ring resonator (PCRR) with four scatters can really function as a wavelength division multiplexer. The significance of the design is that the output waveguide is perpendicular to the ring resonator. We numerically demonstrate that the proposed four-channel PCRR device with 3 x 3 inner dielectric rods can provide a transmission efficiency larger than 92%, a quality factor higher than 3800, and crosstalk of less than -32 dB.

New design of four-channel add-drop filters based on double-resonant cavity photonic crystals

We proposed a new double-resonant cavity four-channel add-drop filter based on the in-plane type two-dimensional (2D) photonic crystal with square lattice. Through this novel double-resonant cavity, WDM signals can be coupled in or out of the bus waveguide with 100% add-drop efficiency while completely prohibiting cross talk between the bus and the add-drop waveguides for all other wavelengths. This device could be used as an optical add-drop multiplexer (OADM) in coarse wavelength division multiplexing (CWDM) applications.

Thirty-two-channel dense-wavelength-division multiplexer based on cascade two-dimensional photonic crystal waveguide structure

The 32-channel dense-wavelength-division multiplexer is composed of the artificial point and line defects in the cascade two-dimensional photonic crystal waveguide with square lattice. The point defect traps the photons propagating through the line defect and emits to free space by the resonant effect. The cascade structure could overcome the mini-stop-band effect and established a continuous-wavelength multiplexing characteristic. The wavelength spacing of 0.8 nm (frequency spacing of 100 GHz), the interchannel cross talk of approximately −21 to −32 dB, and high quality factor Q of 12,500 were achieved through theoretical simulation. It would be a potential component in the application of ultra-high-speed and ultra-high-capacity optical communication and optical data processing systems.

Analyzing multilayer optical waveguides with nonlinear cladding and substrates

A general method for analyzing a multilayer optical waveguide with nonlinear cladding and a nonlinear substrate is presented. This method can also be used to analyze a waveguide with a multiple-quantum-well structure and a multibranch waveguide with nonlinear cladding and a nonlinear substrate. Numerical simulation results show that the analysis is correct.

All-optical switch based on the local nonlinear plasmonic Mach-Zehnder interferometer waveguides

A new all-optical switch based on the local nonlinear metal-insulator-metal (MIM) plasmonic Mach-Zehnder interferometer (MZI) waveguides was proposed. We used the finite-difference time-domain (FDTD) method to simulate the proposed structure. The numerical show that the proposed local nonlinear MIM plasmonic MZI waveguide structure could really function as an all-optical switch.

General method for analyzing the multilayer optical waveguide with nonlinear cladding and substrate

A general method for analyzing the multilayer optical waveguide with nonlinear cladding and substrate is presented. This method can also be used to analyze the multi branch waveguide. Numerical simulation results show that the analysis is correct.

Proposal for a New Dense Wavelength Division Multiplexing Filter Based on Two-Dimensional Photonic Crystal Ring Resonator

Abstract A new optical filter design based on a two-dimensional photonic crystal ring resonator structure with an N-channel model is proposed in this article. This study also shows that modifying the scatter radius and the waveguide width can significantly improve the performance of the original structure, which can solve the mode mismatch problem for output waveguide. Here, an example of a 16-channel photonic crystal ring resonator is provided; wavelength spacing of 1.6 nm and a high quality factor Q of 6,000 were achieved. The optical filter would be a potential key component in the application of dense wavelength division multiplexer devices.

The study of plasmonic elliptical dimer nanoantennas with different geometry

In this paper, the electrical property of a geometric optimization with elliptical shape dimer nanoantennas has been studied. Numerical calculations are based on the method of finite-difference time-domain (FDTD). Three types of elliptical shape dimer nanoantennas with different geometrical parameters were considered, namely, horizontal dimer, parallel dimer, and parallel-horizontal dimer. We have found that plasmonic nanoantennas with the horizontal dimer embedded into a 1D double-arm grating system provide strong electric field enhancement as compared with the others.

High-frequency characteristics and equivalent circuit model of a TO-46 header for 25-Gb/s applications

The TO-46 header used for high speed VCSEL or PIN-TIA package is characterized through a specially designed K connector experimentally. An equivalent circuit model of the TO-46 header has been extracted. The TO-46 header is shown to be capable to be used in 25 Gb/s applications.