This study presents a systematic optimization procedure to generate slow light with large group index, wideband, and low dispersion in an lattice-shifted photonic crystal waveguide. The waveguide is based on triangular lattice photonic crystal imposed by selectively altering the locations of the holes adjacent to the line defect. Under a constant group index criterion of +/- 10% variation, when group indices are nearly constants of 24, 33, 46, 57, and 66, their corresponding bandwidths of flat band reach 24.2, 17.6, 12.8, 10.1 and 8.6 nm around 1550 nm, respectively. A nearly constant large group index -bandwidth product (GBP) of 0.37 is achieved for all cases. Low dispersion slow light propagation is confirmed by studying the relative temporal pulse-width spreading with the 2-D finite-difference time-domain method.

Tuning of the operating wavelength of slow light in the slotted photonic crystal waveguide using microfluidic infiltration has been investigated. Using 2D plane wave expansion method, we numerically demonstrate that the operating wavelength can be shifted from the C to L band, simply by choosing the refractive index of the infiltrated fluid. It is also found that, as the refractive index of the infiltrated fluid changes, the group velocity dispersion has slight variation at different operating wavelength. This design opens the possibility for post-fabrication scheme of tuning the operating wavelength of slow light in slotted photonic crystal waveguide, and allows the device to be optimized for different applications.

Constellation networking is the prominent technology for the next generation satellite systems. The communication schedule is a key problem for constellation maintenance. However, the traditional SRS (Satellite Range Scheduling) model do not use inter-satellite links. In this paper, a communication scheduling model is proposed, in which the ISLs (Inter Satellite Links) is built. And the NP complicity of SNRS is proved. Meanwhile, a two stage greedy algorithm is designed to calculate the SNRS. And heuristic strategies in the proposed algorithm are compared by simulation. The experiment results show that EDF strategy combined with minimum distance route can bring into an acceptable schedule.

We present a procedure to generate wideband and low dispersion slow light in slotted photonic crystal waveguide. By shifting the first and second rows of air holes of slotted photonic crystal waveguide, the bandwidth of slow light can be increased, with small group velocity dispersion. Using 2D plane wave expansion method, we numerically demonstrate slow light with the nearly constant group indices of 23, 42, and 54 over 17.6nm, 6.7nm and 3.3nm bandwidth, respectively. The maximal normalized delay-bandwidth product is 0.26. From the fabrication's point of review, shifting the position of holes is easier to be controlled technically than changing the diameters of air holes. In addition, our simulations suggest this design is tolerant to deviation for positions of the first two rows of air holes. Therefore, the proposed approach decreases the dependence on the fabrication accuracy.

A slotted single-mode photonic crystal waveguide with a linear tapered slot is presented to realize slow light,whose dispersion curve is shifted by changing the slot width.When the slot width is reduced,the band curve shifts in the tapered structure,and the group velocity of light approach zero at the cut-off frequency.Therefore,different frequency components of the guided light are slowed down even localized along the propagation direction inside a tapered slot photonic crystal waveguide.Furthermore,this structure can confine slow light-wave in a narrow slot waveguide,which may effectively enhance the interaction between slow light and the low-index wave-guiding materials filled in the slot.In addition,this tapered slot structure can be used to compensate group velocity dispersion of slow light by modifying the structure,thus opening the opportunity for ultra-wide bandwidth slow light.

We study numerically the focusing effects when a Gaussian beam pass through a two-dimensional photonic crystal consisting of triangular structure of air holes. By using plane wave expansion (PWE) and finite difference time domain (FDTD) methods, we find the width of convergent beam is about 2μm. Meanwhile, the focusing effects also are influenced by the Gaussian half-width, the numbers of the layers and the incident angle. The structure can be used for light-coupling and near-field scan image application.

As a very effective scheme to realize channel acquisition, clustering-based channel estimation algorithms have been proposed for optical fiber communication systems with a maximum-likelihood sequence estimation receiver. These algorithms can estimate the key channel parameters needed by the Viterbi processor accurately without assuming that the channel memory length is known a priori to the receiver. In this work, a corresponding adaptive channel tracking algorithm is proposed, which is proved to be very powerful in tracking the variation of the communication channel. Cooperation of the clustering-based channel acquisition and channel tracking is realized.

A single-mode photonic crystal waveguide with a linear tapered slot is presented, which can localize light spatially by changing the slot width. Its effective bandwidth is 52nm, from 1500nm to 1552 nm. Along the tapered structure, the slot width is reduced, and the corresponding band curve shifts. The group velocity of light becomes zero at the band edge. Therefore, different frequency components of the guided light are slowed down and finally localized at correspondingly different widths inside a tapered slot photonic crystal waveguide. Furthermore, this structure can confine light wave in a narrow slot waveguide, which may effectively enhance the interaction between light and the low-index wave-guiding materials filled in the slot.