Papers by Keyword: Photonic Crystal Waveguide

Abstract: A two-dimensional (2D) triangular lattice photonic crystal coupled-cavity waveguide is designed and optimized. The transmission spectrum of the PC waveguide with TE polarization is calculated by using the finite-difference time-domain (FDTD) method, and the group velocity of c/131.18 at the wavelength is obtained. Through optimizing the parameters of photonic crystal waveguide, different resonance length are obtained by changing the number of the continous air holes. The smallest group velocity is obtained to be c/2209 in the coupled-cavity waveguide with 15 air holes. The mechanism of slow light in the coupled-cavity waveguide of photonic crystal is analyzed.

Abstract: Using of cascaded multimode interference waveguides in 2D photonic crystal power splitter are investigated by modeling and computation. Results show that with a five line defect waveguides and one pair of three line defect waveguides integrated, the total normalized transmission can be high as 94.9% with 30nm broad spectrum calculated and simulated by finite-difference time-domain method.

Abstract: In order to filter, we use the coupling methods of line defects and point defects in photonic crystals to verity through theories and experimentations, get micro-cavity center frequency and wavelength of the main waveguide frequency resonance, and the same frequency lights will enter micro-cavity. Results show waveguides and micro-cavity can support its modes within in their deficiencies, but defects still can transfer energies through the evanescent coupling, the evanescent coupling is the role of the photonic crystals to the integration of device.

Abstract: A guided mode of positive and negative group index structure is essential to quantum optics for design and development of high efficiency optical devices which are useful to security optical communication system and to diverse applications such as Optical Time-Division-Multiplexing, Optical Switch, Laser, LED, Entangled Photon Source and Single Photon Source. Thus, we proposed to develop an efficient photon emission along line defect of two-dimensional honeycomb photonic crystal waveguide in the silicon slab. The honeycomb lattice of circular air holes on a silicon plate is simulated to obtain two nearest guided modes between positive and negative group index regimes. This significant property shows the potential applied guided modes of photonic crystal waveguide enhancing spontaneous emission for controlling photon emission between two resonance frequencies. Significantly, this work is oriented to produce the novel optical devices for control photon emission in the optical communication system. In addition to the honeycomb lattice, it can easily be made on a Si on insulator (SOI) wafer.

Abstract: In this paper, we report the experimental measurements of the group index of a photonic crystal waveguide based on silicon-on-insulator slab. The time-delay of the pulse is also measured, and it is in good agreement with the theoretical result calculated according to the group index with the phase-delay method, which is about 4.7ps.

Abstract: In this paper, we designed and analyzed an efficient taper structure to couple light into and out of photonic crystal waveguides (PhCWs) fabricated by Si-ion implantation and electron beam lithography. The coupling structure employs the gentle refractive-index distribution produced in the SiO₂ layer by Si-ion implantation. A taper structure is designed for effective coupling of transverse electric (TE) polarized light (λ = 1.55 μm) into a submicron size PhCW consisting of triangular lattice of air holes (lattice constant, a = 0.666 μm, radius of air holes, r = 0.232 μm, waveguide width, W1 ~ 0.7 μm). The influence of the taper length on the transmission characteristics is investigated. Efficiency in excess of 95% is demonstrated using the finite-difference time-domain and beam propagation methods. This is important for their practical applications in photonic integrated circuits.

Abstract: We study modes excitation with input field of different positions in five-mode photonic crystal waveguides of triangular lattice. The five-mode photonic crystal waveguides is formed by removing five rows rods in 2D photonic crystals of a triangular lattice of dielectric rods in air. The 0th mode, the 1st mode and the 2nd modes are selectively excited. The input field with different positions can excite different modes due to the field intensity distribution of modes. When the input field locates at the position of the zero field intensity of the waveguide mode, the mode can not be excited. The superposition of different modes can leads to different field intensity distribution. The finite-difference time-domain method is used to obtain the excited field distributions.

Abstract: A photonic crystal waveguide coupled structure can be constructed by putting three photonic crystal waveguides in parallel and adjacent form. Study the coupling of the approximate solution interference acts and the self-image phenomenon of this multi-mode waveguide system based on the guided mode propagation analysis method, a three-channels multimode interference wavelength division multiplexing is designed. The presented device not only has a high transmission rate, but also has the advantages of multiple wavelength selection and may have potential and practical applications in the field of photonic integrated circuits in future.

Abstract: There are two types of coupling structures for the photonic crystal of triangular array of air holes. The two types of coupling structure between dielectric taper waveguide(DTW) and photonic crystal waveguide(PCW) is investigated. The coupling transmission efficiency is calculated for different coupling structure of the input and output, we found that the coupling transmission efficiency is changed with different coupling width and distance. The highest transmission efficiency is 92.6% and 99.6% for the input and output port respectively.

Abstract: We investigate modes excitation with input field of different positions in three-mode photonic crystal waveguides. The three-mode photonic crystal waveguides is formed by removing three rows rods in 2D photonic crystals. The input field with different positions can excite different modes due to the field intensity distribution of modes. When the input field locates at the position of the zero field intensity of the waveguide mode, the mode can not be excited. The finite-difference time-domain method is used to obtain the excited field distributions.