Ming Che

We developed a thermo-optic effect based silica optical phased array (OPA) chip and evaluated its tunability of phases of lightwaves. The THz waves, whose phases are controlled by the OPA chip, are generated from four arrayed uni-travelling-carrier photodiodes (UTC-PDs) based on heterodyne photomixng. Meanwhile, the UTC-PDs, which integrated with 4×4 slot antennas, are fabricated on a monolithic InP substrate chip for 300-GHz wave beam combining and steering. Through the optoelectronic THz-wave

In this study, generating and enhancing THz continuous/pulsed waves is achieved by fabricating a monolithic InP substrate chip of arrayed photomixers, where each photomixer includes an InP/InGaAs uni-traveling-carrier photodiode (UTC-PD) with integrated 1 × 4 planar slot antennas (PSAs). Through optoelectronic time-aligned and -gradient delays of lightwaves that couple to arrayed photomixers, the radiated THz waves yield both quantitative gain and spatial directional gain. To generate continuous

This paper presents the implementation of a face detection algorithm on FPGA for an eye mouse control system. An improved algorithm of skin color module and binary image projection is used to ensure real-time detection. The system is based on a hardware/software co-design, which consists of a dedicated hardware accelerator that solves the parts of the algorithm with higher computational cost and an embedded microprocessor that manages the control process and executes the rest of the algorithm. S

We have developed a plane-wave transfer-matrix method (PWTMM) with the aid of the interpolation technique to analyze the dispersion relation of surface modes in photonic crystal or photonic crystal surface waveguide. The proposed approach has been applied to several surface structures in two-dimensional photonic crystals. The calculated dispersion relation of the surface modes is in good agreement with the result obtained by the conventional plane-wave expansion method in combination with the su

We have developed a plane-wave transfer-matrix method (PWTMM) to analyze light propagation through sharp photonic crystal bend structures. With the aid of the supercell technique, the original aperiodic waveguide bend can be modeled by a periodic scattering problem of two semi-infinite photonic crystal waveguide arrays face to face or two semi-infinite photonic crystal waveguide arrays separated by a sandwiched slab of bend region. The proposed approach has been applied to several sharp bend str

Terahertz (THz) pulses with picosecond-level duration are generated and enhanced by fabricating arrayed InP/InGaAs unitraveling-carrier photodiodes (UTC-PDs) with integrated planar bowtie antennas. We experimentally demonstrated THz pulses generation from an UTC-PD with a duration of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$10 \,\mathrm{ps}$</tex-math></inline-formula> and <inline-formula xmlns:mml="http

We developed a THz-wave power-combination and beam-steering system driven by an optoelectronic phased array. The 300-GHz waves from an antenna-coupled InP/InGaAs UTC-PD array are combined with 16-dB gain and steered continuously over a 30° range.

An electro-optic frequency comb is heterodyne down-converted by a uni-traveling-carrier photodiode (UTC-PD) to a broad spectrum in the range from DC to THz band. As a result, a pulsed THz train with a repetition rate of 25-GHz was generated which is an envelope or averaged intensity of optical pulses. To generate steerable THz pulsed beam, we fabricated a monolithic InP substrate photonics integrated circuit that includes a uniform linear array of four InP/InGaAs UTC-PDs with integrated bow-tie

Artificial optical birefringence can be realized in three-dimensional photonic crystals with a uniaxial structural symmetry: e.g., woodpile photonic crystals with a tetragonal lattice structure in the long-wavelength limit. The ordinary and extraordinary indices of refraction are determined from calculation of the reflection coefficient for a plane wave incident on the surface of a semi-infinite photonic crystal at different angles. We find that the anisotropy can be widely tuned by simply chang

We have proposed an optically controlled THz power tuning method based on THz wave interference. Through interfered THz waves at the T-junction transmission line, adjustment of the THz power is achieved, and tuning control is attained by varying the optical time delay of the beat-note lightwaves. To demonstrate and verify THz power tuning with an optical delay line, we have also fabricated a monolithic chip on an InP substrate, which integrates arrayed uni-traveling-carrier photodiodes and a pla

Photonic band gap(PBG) structures of the two-dimensional magnetic photonic crystals (MPCs) are calculated by use of the plane-wave expansion method. The MPCs consist of magnetic pillars in rectangular, square, hexagonal and circular shapes, respectively embedded in dielectric medium in a square lattice. The optimal MPC samples that possess the largest gap-mid gap ratio for each type of MPC are obtained by scanning the three parameters(permeability, filling factor and rotating angle). The changes

The multi-dimensional carrierless amplitude and phase (MD-CAP) modulation is a high spectral efficiency modulation technology which has begun to draw more attention in recent years. Meanwhile, how to improve the energy efficiency is also an important issue within the limited bandwidth. In this paper, a 3D-CAP modulation with trellis coded constellation has been proposed. At the premise of increasing the transmission bandwidth, the bit error rate is reduced through the unified design of channel c

We propose a technique, based on three-dimensional (3D) plane-wave transfer-matrix method, to analyze light propagation through two-dimensional (2D) photonic crystal (PC) slab waveguide bend structures. By means of the supercell technique, the waveguide bend is modeled by two semi-infinite 3D periodic arrays of 2D PC slab waveguides face to face or separated by a sandwiched slab of bend region from which the intrinsic transmission, reflection, and radiation loss coefficients of waveguide modes c