Spectrum Availability Aware Routing and Resource Allocation for Point-to-Multipoint Services in Mixed-Grid Optical Networks

Mixed-grid optical networks are in a migration state where fixed-grid and flex-grid optical networks coexist. To carry point-to-multipoint (P2MP) services in mixed-grid optical networks, routing and resource allocation (RRA) problems need to be solved. Once the RRA fails, services will be blocked and then influence quality of service. The minimized spectrum for satisfying the bandwidth request of services is called as a frequency block (FB). For a service, the total number of available FBs embodies the spectrum availability on a link. Because the fixed-grid and flex-grid links have different channel spacing, spectrum availability on fixed-grid and flex-grid links needs different evaluation method. We propose a RRA algorithm in mixed-grid optical networks for P2MP services by being aware of spectrum availability. The spectrum availability is evaluated according to fixed-grid and flex-grid constraints. Our proposed algorithm achieves the lower blocking probability (BP) than that of benchmark RRA algorithms according to simulation results.

Demultiplexer of Multi-Order Correlation Interference in Nitrogen Vacancy Center Diamond

We reported the second- and third-order temporal interference of two non-degenerate pseudo-thermal sources in a nitrogen-vacancy center (NV−). The relationship between the indistinguishability of source and path alternatives is analyzed at low temperature. In this article, we demonstrate the switching between three-mode bunching and frequency beating effect controlled by the time offset and the frequency difference to realize optical demultiplexer. Our experimental results suggest the advanced technique achieves channel spacing and speed of the demultiplexer of about 96% and 17 ns, respectively. The proposed demultiplexer model will have potential applications in quantum computing and communication.

Investigation on Ultra-compact 2DPC Coarse Wavelength Division Demultiplexer

A two dimensional Photonic Crystal (2DPC) based eight channel wavelength division demultiplexer is proposed and designed for Coarse Wavelength Division Multiplexing (CWDM) applications. The circular ring resonator, channel selector, circulator rod, L bend waveguide and linear bus waveguide are essential parts of the proposed system. The system’s functional parameters such as Transmission efficiency, resonant wavelength, spectral width, channel spacing, Quality factor and crosstalk are investigated in this paper. The eight different wavelengths of channels are filtered out by altering the size of channel selector rod, setting the radius of the circle shaped cavity and relative refractive index of circulator rod. Initially the Photonic Band gap (PBG) is manipulated by applying Plane Wave Expansion (PWE) method of the 2DPC structure. The functional parameters are analysed by Finite Difference Time Domain (FDTD) method in periodic and non-periodic structure of the proposed system to arrive normalized transmission spectrum. The resonant wavelengths of designed eight paths of the device are varying from 1420nm to 1460nm with average spectral width and channel spacing are 5.8nm, 5.6nm respectively. The footprint of the device is 286.84µm2. Hence this small device can be implemented for CWDM systems in Photonic Integrated Circuits (PIC).

Investigation and optimization of EYDFA + Raman + EYDFA hybrid optical amplifier for SD-WDM systems in C+L band

In this paper, we present a novel erbium–ytterbium doped fiber amplifier (EYDFA) + Raman + EYDFA hybrid optical amplifier (HOA) for a super-dense wavelength division multiplexing (SD-WDM) system application. The performance of the 100-channel system has been investigated for an overall data rate and channel spacing of 100[Formula: see text]Gb/s and 0.4[Formula: see text]nm, respectively, over a wavelength span of 1550–1589.9[Formula: see text]nm. HOA has been optimized for Raman length, EYDFA lengths, pump powers and Er[Formula: see text] concentrations to achieve high average gain and low gain variation ratio of 40.41[Formula: see text]dB and 0.40[Formula: see text]respectively. The optimized configuration of the proposed HOA has been compared with EYDFA + Raman and Raman + EYDFA HOA configurations. The achieved high and flat gain with an acceptable output optical signal to noise ratio (OSNR) in case of EYDFA + Raman + EYDFA HOA; makes it an optimum choice for SD-WDM systems.

Detailed numerical simulation and experimental investigation on micromixers with serpentine Koch fractal microchannels

Micromixer is a kind of microfluidic chip for fast mixing and analysis. Mixing in a micromixer is usually a micron scale. At low Reynolds number, the fluid in the channel is laminar flow, which mainly depends on molecular diffusion as the main mixing mode. Fluid mixing in microchannels is very difficult, especially when the viscosity of the fluid is high. In this paper, we design a novel passive micromixer. The effects of fractal number, Koch fractal channel spacing, microchannel depth and cross-section shape on mixing efficiency were studied. Through a large number of numerical simulations, we continue to optimize the structure of the micromixer and improve the mixing efficiency. Finally, through the continuous optimization of the structure of the micromixer, the mixing efficiency of the micromixer can reach more than 95%.

Optimization of the separation paraments in inclined channels of liquid-solid fluidized bed

A new theoretical formula can be used to calculate superficial velocity for particle separation with a critical condition, and it is based on the size, density, terminal velocity, Reynold number of the particle and equipment parameters. In a continuous system, a series of fractionation experiments were conducted to quantify the separation performance for 0–2 mm coal particles under various factors, including channel spacing, solids throughput and split fluidization rate. The separation performance considers the ash content and yield of products varying with the particle size. A great fluidization environment can be created by the 6 mm channel spacing. For the solids throughput of 10.20 t/(m2h) provides a well effective separation in the narrow channels. In addition, the split fluidization of 0.0058 m/s can produce a higher shear induce force in the inclined channels to prevent the low-density particles from being lost in the underflow. The theoretical superficial velocity calculated by the new formula is 0.042 m/s, which can report the particles with the upper and lower size reach at 9-fold to the overflow, it is almost the same as the actual separation fluidization velocity of 0.04 m/s. Meanwhile, the data obtained under each separation condition is basically consistent with data of the sink-float mothed, which shows a good separation performance for the Reflux Classifier.

WDM-Based 160 Gbps Radio Over Fiber System With the Application of Dispersion Compensation Fiber and Fiber Bragg Grating

The demand for data transmission is rising expensively for the applications of biomedical sensors data, multimedia technologies, and ultrahigh-definition online video streaming. Such applications require larger bandwidth with minimum latency and seamless service delivery. Radio-over-fiber (RoF), integrated with wavelength division multiplexing (WDM) technology, is being considered one of the promising technologies. However, the integration of optical fiber and wireless communication also generates non-linear effects as and when the number of users increases. That results in the introduction of signal noise, unwanted frequencies, low quality of signals, and increased latency. In this paper, a 16-channel 160 Gbps data rate WDM-based RoF system has been simulated and evaluated for optimum performance at a variable input power level, from 5 to −15 dBm, with the application of dispersion compensation fiber (DCF) and fiber Bragg grating (FBG), with channel spacing of 50 and 100 GHz. The performance of the system is evaluated with the existing WDM-RoF system. The performance metrics parameters chosen for evaluation are bit error rate (BER), quality factor (Q-factor), and eye diagrams and simulated on opti-system simulator. The optimum performance has been observed at a power level of −5 dBm for all these elected evaluation parameters. It has also been observed that, for channel spacing of 100 GHz, the network performed better in comparison with 50 GHz.