For stimulates great developments in high-speed and high-capacity Cloud Computing Technologies (CCT) systems in the
future. The all-optical logic gate based on planar photonic crystal (PPC) waveguide is a promising technology. We design
an all-optical AND gate in PPC, as an ultracompact component for planar lightwave circuit integration with suitable
choice of parameters, perform this task. The PPC waveguides are composed of circular dielectric rods set in
two-dimensional triangular lattice. To realize the AND logic function, as predicted using 2D finite-difference
time-domain simulations. The combination of the ring and line defect coupler waveguides forms the device. On the basis
of our simulations, we found that the optimized scheme maximizes the power transmission above 80% at a wavelength
of 1.55 um. Besides, this device can apply to all-optical Arithmetic Logic Unit (ALU) in all-optical computing and
potentially applicable for photonic integrated circuits (PICs) in the future.
All-optical logic gate is a basic and crucial element for optical signal processing. In this paper, we propose a 4×2 encoder
based on two dimensional triangular lattice photonic crystals composed of cylindrical silicon rods. The main structure of
the device is a combination of both line defect Y branch and coupler photonic crystal waveguides. The computational
simulation is carried out by using a finite-difference time-domain (FDTD) method. The simulation results show that the
proposed all-optical photonic crystal waveguide structure could really function as a 4×2 encoder logic gate. In addition,
the distance between coupler photonic crystal waveguides, the length of coupler waveguides and the distance between
line defect Y branch waveguide structure are optimized for achieving the optimal performance for the proposed encoder
logic gates. This device is potentially applicable for photonic integrated circuits.
All-optical logic gate based on photonic crystal waveguides is a promising technique in future high-speed all-optical
signal processing. In this paper, we propose a XOR logic gate based on two dimensional triangular lattice photonic
crystals composed of cylindrical silicon rods in air. The main structure of the device is a line defect asymmetric Y
branch waveguide. It is expected that there should be a phase shift between the two input beams. Hence, if an
appropriate initial phase is introduced, the two input beams may interfere constructively or destructively to realize the
logical functions. The simulation results show that the proposed all-optical photonic crystal waveguide structure could
really function as XOR logic gates. The interference section length and width of photonic crystal waveguide structure
are optimized for achieving the optimal performance for the proposed XOR logic gates. This device is potentially
applicable for photonic integrated circuits.
A novel structure of an electronically tunable Fabry-Perot interferometer is proposed. It consists of double layers of homogeneously aligned liquid-crystal films with the buffing direction orthogonal to each other. A pure resonant wavelength, for excellent polarization-independent properties, was obtained, as both theoretical and experimental results show. It is demonstrated that the power fluctuations are less than 0.5 dB and the extinction ratios up to 7dB for our devices.
In this paper, we have demonstrated two types of polymer waveguide switches with nematic liquid crystal cladding. Although the higher propagation loss in LC materials hinders them from serving as the waveguide film, it has been common that LC exhibiting a large optical anisotropy and an electrically controllable molecular alignment are applied to investigations of slab-waveguide cut off switching as active medium claddings. For this type of switching geometry, a higher contrast ratio is obtainable because simple TE or TM polarized waves may be supported in the planar polymer waveguide.
We propose a wavelength-insensitive optical TE-TM polarization mode converter using twist nematic liquid crystal cell for multi-mode or single-mode fiber communication systems application. Based on the simple and widely used TNLC cell structure, the optical converter has the potential advantages such as inexpensive, simple fabrication processes, and easy mass production. The low crosstalk of -28.3 dB is obtained.
We propose a wavelength-insensitive optical switch using twist nematic liquid crystal display (TN-LCD) panel for multi-mode or single-mode fiber communication systems application. Based on the simple and widely used TN-LCD structure, the optical switch has the potential advantages such as inexpensive, simple fabrication processes, and easy mass production. The preferable operating frequency of the device is 0.1 k to 10 k Hz ac wave. The critical and saturated voltage are as low as 3 Vrms and 5.8 Vrms, respectively. The high extinction ratio of 28.3 dB is obtained.
We have demonstrated the fabrication and characterization of polymer- based optical waveguides. Reported here is a fabrication technique for polymeric channel waveguides with the inverted-rib structure. The waveguide is consisted of a polymer film spin-coated on the SiO2/Si substrate, in which channel grooves are pre-patterned to provide lateral optical confinement. Moreover, modal characteristics of the waveguides for a TE-polarized light source at 632.8 nm are also calculated and measured for comparison using the Galerkin's method and the Laser beam analyzer, respectively.