Advanced Materials Research Vol. 979

Abstract: The effective numerical aperture calculation in two-dimensional Photonic crystal waveguide has been proposed. In this paper we present the analysis of ray optics refracted inside nanorods and at the boundaries between rods, which separates rod gap is much smaller than the incident wavelength assumed to reflect on the region. In operation, the resolving numerical aperture was compared with the finite difference time domain method via OptiFDTD software. Although numerical aperture mentioned above was found to be extremely close to fiber optics, a transmission passes though compartments of the rods are observed due to significant estimation of transmission and reflection of electric field. The compared simulation results will be discussed. By the aforementioned is that in the near future we will modify wave equation in periodic media of waveguide structures reached to the transverse electric equation of beam propagation in the two-dimensional Photonic crystal waveguide analysed.

Abstract: A frequency-stabilized diode laser is widely used for applications in laser cooling and high-resolution spectroscopy. In this work, the 780-nm external cavity diode laser was constructed and subsequently frequency-controlled by three parameters, i.e., temperature, injection current and optical feedback. The laser frequency was measured with respect to the 5S_1/2 → 5P_3/2 (D2-lines) transition of Rubidium, while the laser mode was characterized by a Fabry-Perot interferometer. The laser temperature was passively controlled to a single value between 20 ̊C and 25 ̊C while the injection current was investigated in combination with course and fine adjustments of optical feedback. Only data relevant to a single-mode laser operation was collected. It was found that as the current increased, the laser frequency shifted linearly with slopes approximately 0.5-0.8 GHz/mA. Optical feedback from the external cavity was tuned by the voltage applied to the piezoelectric transducer, yielding a linear frequency response of approximately 0.2 GHz/V. The measured parameters were rearranged to represent the island of stability of the laser, suggesting suitable conditions that yielded single-mode operation, at a desirable laser frequency. The results were important for a design of an active feedback, in order to further reduce the frequency linewidth and intensity noise of the laser.

Abstract: Phase shifting interferometry based on Michelson interferometer is purposed to measure surface roughness of glass slides which are widely used as substrates for thin-film coating processes. For the interferometry system, an optical flat with a flatness of λ/20 is used as a reference mirror. The high accuracy of the phase shifting is achieved by a piezoelectric-driven linear translation stage of the reference mirror. The reference-phase difference between the two-interfering beams is shifted by every π/2 in phase shifting. Five frames of interferograms under various phase differences of 0, π/2, π, 3π/2 and 2π are recorded by a CCD camera. Each image pixel of these frames is interpreted to access interference intensity information by five-step phase shifting algorithm for phase calculation, which in turn relates to surface height. The purpose-built interferometry is tested by the surfaces of two optical flats with flatness of λ/10 and λ/4, which are used as the test surfaces. Our measured flatness results are consistent with those of the commercial optical profilometer. The usefulness of the purpose-built interferometry is demonstrated on two types of the glass slides. Aluminum thin films are also deposited on these glass slides by the RF magnetron sputtering method to enhance reflectivity of the glass slide surfaces. The surface profiles and flatness parameters of these glass slides have been reported.

Abstract: In this paper, a numerical analysis of an optical double ring resonator is presented. The numerical results show that the free spectral range of double ring resonator at certain parameters is much higher than that of single ring resonator although double ring resonator gives some ripples on the pass band.

Abstract: This paper proposed a scheme for multi channels THz frequency generation by using a coupled nonlinear resonator device known as PANDA ring. Dipole gold nanoantenna coupled to active plasmonic devices was used at THz for WiMAX network applications. Multiple Dark-Bright soliton conversion control propagating within a modified PANDA ring resonator to generated dense wavelength division multiplexing (DWDM).The system results illustrated multi wavelength Dark-Bright soliton generation and the frequency obtained in multi THz frequency to broadcast the data to transmitter for all receivers. In this approach, the muti THz frequency provides a reliable frequency band for the future planar lightwave circuit (PLCs) based on DWDM optical link with Wi-Fi, WiMAX, Ubiquitous, and many applications.

Abstract: The samarium-doped lithium-gadolinium borate [60Li₂O:10Gd₂O₃:(30-x) B₂O₃:xSm₂O₃] (LGBO:Sm³⁺) glasses have been melted and quenched in stainless plate under an air atmosphere. Some physical and optical properties within wavelength concerned and photoluminescence of the LGBO:Sm³⁺ glasses were measured and discussed. The density of glasses dropped until 0.10 mol% and tends to increase after that point, while molar volume of the glasses tends to increase with concentration of Sm₂O_3.. In absorption spectra, there are 2 obvious peaks in UV-VIS range and 6 peaks in NIR range indicating the Sm³⁺ in glass matrices. The sharpness of a peak, in the absorption spectra, also increases with concentration of the dopant. The 7 obvious peaks in excitation spectra represent the transitions from the ground state ⁶H_5/2 to various excited states. Furthermore, The emission spectra were observed under 404 nm light from the Xenon compact arc lamps, and showed the concentration quenching effect (CQE) at 1.00 mol% of Sm³⁺. Additional, The lifetimes showed decreasing trend with concentration of Sm₂O_3.. As the result, The LGBO:Sm³⁺ glass doped with 1.00 mol% of Sm³⁺ gives the highest result for luminescence properties.

Abstract: A system that can be used to generate the new optical communication using a Gaussian pulse propagating within a nonlinear microring resonator double add/drop multiplexing system is discussed. By using the wide range of the Gaussian input pulses, for instance, when the input pulses of the common lasers with center wavelengths 1,300 nm are used. Achievements obtained have shown that very high capacity more than 300 channels for optical communication.

Abstract: We propose a new design of the mesh ring resonator system device using the nonlinear behaviors of optical pulse propagation in the ring resonator system, where the disadvantages of nonlinearity of light pulses propagating in the propose system becomes beneficial. The simulation results obtained have shown the chaotic output signals that can be generated by Kerr effects in the ring resonator system, where the bits logic decision signals can be controlled by using the specify system parameters, the ring radii, the coupling coefficient and the threshold outputs intensity, of the proposed simulation system. The potential of using such the mesh ring resonator system device for optical communication security application is performed and discussed.

Abstract: We propose a new method using light pulses tracing in a micro ring resonator, where the randomly digital codes can be performed. The chaotic signals can be generated and formed by the logical pulses by using the signal quantizing method, which can be randomly coded by controlling the specific optical input coupling powers, i.e. coupling coefficient (κ) and ring radii. Simulation results when the ring radius used are between 7-10.0 μm, and the other selected parameters are close to the practical device values that are presented and discussed. The random codes can be generated by the random control of coupling powers, which can be transmitted and retrieved via the design filters by the specific clients. We can be controlled input power used are between 2.0 and 5.0 mW, whereas the quantizing threshold powers and the traveling roundtrips are 0.3–0.4 mW and 8000–10,000, respectively.

Abstract: We propose a study triple ring resonator using a Gaussian pulse within the triple ring resonator system, whereas the chaotic signal can be generated within a microring device. We have also theoretically shown that the optical non-linear behaviours can be controlled and tuned by varying the couple coefficient (κ) between 0.20 and 0.95, with ring resonator radii between 10 and 20 μm, which is available for suitable result for communication. In application, the transmission of optical communication system , quantum communication and dens wavelength multiplexing.