Search

Increasing mobile traffic and smart devices require continuous expansion of optical access network capacity and easy optical connectivity for residential, business, and mobile services. A high-speed TDM-PON system with high power budget is an attractive solution to accommodate explosive mobile traffic since multiple remote nodes with simple optical power splitters could easily provide optical connections anywhere in an optical distributed network. Thus, both high speed per wavelength and high-power budget are desirable in the TDM-PON system. We demonstrate a TDM-PON system with 50 Gb/s/λ with PAM4 and 35-dB power budget in the entire O-band by simply operating a booster SOA in the saturation region. In addition, a dynamic range of 50 Gb/s PAM4 receiver higher than 15 dB is demonstrated to support loud-soft ratio. We also successfully demonstrate error-free transmission of 50 Gb/s TDM-PON system by utilizing an OLT line-card and an ONU board.

InGaAs/InP single-photon avalanche diode (SPAD) with small active diameter and backside microlens was fabricated and its dark count and after-pulse noises were characterized. In addition, by optimizing multiplication layer and reducing the active diameter, high photon detection efficiency (PDE) was achieved as well as suppressed dark count probability (DCP) and after-pulse probability (APP) near room temperature. The gated Geiger-mode characteristics of SPAD were investigated with the gate amplitude of 6.6 V and repetition frequency of 10 MHz. Superior single-photon detection characteristics as PDE of 20.9%, DCP of 1.02 × 10–5 and APP of 0.8% were observed at the operation temperature of + 20 °C. It is a promising result that allows compact and low-cost detector module for quantum key distribution system with simple cooling apparatus.

The long-term reliability of open-tube diffused planar InGaAs/InP APDs was investigated via accelerated life testing in this study. For the proposed life testing scheme, both thermal and electrical stresses were applied simultaneously to reduce the testing periods while maintaining statistical significance. Additionally, the Eyring model was used to extrapolate the activation energy. To determine the optimum life testing conditions, high-temperature storage tests, preliminary accelerated life tests, and main accelerated life tests were conducted. From the test results, the mean-time-to-failure was utilized to verify the suitability of the Eyring model. The proposed testing scheme, which utilizes a hybrid of accelerated stress factors, allows us to estimate the device reliability within an acceptable testing period, minimizing the time to market.

The after-pulsing effect is a common problem in high-speed and low-noise single-photon detection based on single-photon avalanche diodes (SPADs). This article presents a dual anode InGaAs/InP SPAD (DA-SPAD) with two separate anode output ports that can be utilized for discriminating relatively weak avalanche signals, providing a simple and robust configuration of the SPAD-based single-photon detection system. Weak avalanche signals with amplitudes below the amplitude of the parasitic capacitive response of the SPAD were easily detected by the DA-SPAD and a simple subtraction circuit. The gated Geiger-mode performance of the DA-SPAD was also investigated. At a gating frequency of 1 GHz, the detection efficiency was 20.4% with an after-pulse probability of 3.5% at a temperature of -20 °C.

We were analyzed the piezoelectric characteristic for electronics printing to inkjet printing system. These applications were possible use to Actuator, MEMS, FPCB, RFID, Solar cell and LCD color filter etc. Piezoelectric print head is firing from ink droplet control consideration ink viscosity properties. At this time, micro pattern for PCB metal printing was possible by droplet control of piezoelectric driving. These driving characteristics are variable voltage pulse waveform. We are used the piezoelectric analysis software of Finite Element Method (FEM), Piezoelectric design parameters are acquired from piezoelectric analysis, and measurement of piezoelectric. It designed for piezoelectric head to possible electric print pattern of inkjet printing system. For this validity we were established through in comparison with simulation and measurement. Designed piezoelectric specification obtained voltage 98V, firing frequency 10 kHz, resolution 360dpi, drop volume 20pl, nozzle number 256, and nozzle pitch 0.33 mm.

Polymer electrolyte membrane (PEM) fuel cells typically have low voltage, high current, terminal characteristics that cannot accommodate common electric loads like electric motors or power utility grids. Thus, a dc/dc converter is required to boost the output voltage of these power systems. Furthermore, the terminal characteristics are dependent on loads and operating conditions of the fuel cell system. The continuously changing power demand of an electric load requires dynamically replenishing the air and fuel, by properly maintaining humidity in the cell and efficiently rejecting the heat produced. These factors present important challenges for the design of reliable and durable power systems. We present new dynamic models for a fuel cell system and a pulsewidth modulation dc/dc converter with associated controls and integration. The model for the system consists of three subsystems that include an PEM fuel cell stack, an air supply, and a thermal system. Four different controllers were designed to control the air, the coolant, and the output voltage of the converter, and to optimize the power flow between the fuel cell and the output capacitor. The integrated model with its controls was tested using a real-time simulator that reduced computational time and facilitated the analysis of the interactions between loads and the fuel cell components and also allowed the optimization of a power control strategy. The responses of a static and dynamic load show that the power controls proposed can coordinate two energy sources, resulting in improved dynamics and efficiency.

A fuel cell powered system is regarded as a high current and low voltage source. To boost the output voltage of a fuel cell, a DC/DC converter is employed. Since these two systems show different dynamics, they need to be coordinated to meet the demand of a load. This paper proposes models for the two systems with associated controls, which take into account a PEM fuel cell stack with air supply and thermal systems, and a PWM DC/DC converter. The integrated simulation facilitates optimization of the power control strategy, and analyses of interrelated effects between the electric load and the temperature of cell components. In addition, the results show that the proposed power control can coordinate the two sources with improved dynamics and efficiency at a given dynamic load.

This paper analyzed the power loss of transformers considering the magnetic component. For this, each winding strategy and the effect of air gap between the ferrite core have been an important variable for optimal parameter calculation. Inductors are very well known design rules to devise, but the performance of the flyback converter as a function of transformer winding strategy has not been fully developed. The transformer analysis tool used was PExpert. The influence of the insulator thickness, effect of the air gap, how the window height and variation of the capacitive value effects the coil and insulator materials are some of parameters that have been analyzed in this work. The parameter analysis is calculated to a high frequency of 48(kHz). Therefore, the final goal of this paper was to calculate and adjust the parameters according to the method of winding array and air gap minimizing the power loss.

This paper presents ZVZCS(Zero-Voltage and Zero-Current Switching) Three Level DC/DC Converter without primary freewheeling diodes. The new converter presented in this paper used a phase shirt control with a flying capacitor in the primary side to achieve ZVS for the outer switches. A secondary anxiliary circuit which consists of one small capacitor, two small diodes and one coupled inductor, is added in the secondary to provide ZVZCS conditions to primary switches, ZVS for outer switches and ZCS for inner switches. Many advantages include simple secondary auxiliary circuit topology, high efficiency, and low cost make the new converter attractive for high power applications. Also the circulating current flows through the circuit so that it causes the needless coduction loss to be occurred in the devices and the transformer of the circuit The new converter has no primary auxiliary diodes for freewheeling current. The principle of operation, feature and design considerations are illustrated and verified through the experiment with a 1[㎾］ 50[KHz］IGBT based experimental circuit.

The power consumption of electric appliances in the modern home is a useful information source for analysis of user activities along with the location and identity of the appliances. A context-aware residential service system provides proper user-oriented situation-adapted services by using this information. Thus precise power consumption monitoring is essential in order to provide satisfying services. A shunt resistor is used for precise measurement of input current into the appliance but the power consumption range of the appliances is too wide to be monitored by a single fixed resistor. In this paper, we proposed a variable resistance electric current measurement module that consists of multiple resistors and switches and its operation with a service oriented architecture (SOA) based service system. We evaluate an optimal set of the multiple resistors of the module.

In this paper we report direct laser structuring technology for circuit patterning. The laser structuring could replace photolithography and additional processes for manufacturing printed circuit board. The laser structuring can be divided into three steps, injection molding with polymer composite materials, laser emission and electroless plating. These cost-effective three steps could simplify more than 10 steps in photolithographic process, alternatively. The laser structuring has an advantage in curved surface application. Experimental results show that the direct structuring with a power-stabilized pulsed nanosecond laser can be applied for 3-dimensional circuit patterning.

This paper is analyzed for piezoelectric head of Inkjet printing system for micro pattern printing. For this, we are used the piezoelectric analysis software (ALTILA), ink droplet control used piezoelectric print head considered Ink material properties. Inkjet micro pattern of Flexible PCB is printed by droplet control, for this the driving principle of piezoelectric material is drive from bending mode of piezoelectric. Maximum driving of PZT is ink droplet control method considered electronic ink properties. According to, this result was establishment by experiment of FPCB micro pattern printing.

A fuel cell powered system is regarded as a high current and low voltage source. Effects of electric loads on the power source are of importance to design an optimal integrated system. In particular, dynamics of the system should be considered to determine a system configuration and the size of the components. Currently, no integrated simulation has been approached to analyze the effects of the power on the system components. Therefore, the major effort in this paper has been placed on development of dynamic models of the PEM fuel cell powered system that includes a PEM fuel cell stack along with an air supply system, a DC/DC converter and associated controls. Electric loads for the system are assumed as active and reactive power. Finally, the effects of the loads on the fuel cell system are analyzed.

This paper proposes a coupled inductor-based rectifier of a three-level (TL) DC/DC converter and compares the rectification methods of a TL converter. The CICDR-TL (coupled inductor current doubler rectifier three-level) converter achieves ZVS (zero voltage switching) for the switches in a wide load range. CDR (current doubler rectifier) and CICDR three-level converter have low voltage and current ripple. Advantages and disadvantages of topology compared to the rectifier of bridge, center-tap, CDR, and CICDR are discussed. Experimental estimation results obtained on a 27 V, 60 A DC/DC TL converter prototype for the 1.8 kW, 40 kHz IGBT based experimental circuit.

In this paper, the permanent magnet synchronous generator of 1.5 MW output power which is driven directly without gear system is designed by conventional magnetic equivalent circuit method and analyzed by finite element method for verification of design. We analyzed the characteristics of generator like no load, rated load, short circuit condition and demagnetization of permanent magnet. The last, the analysis results of two kinds of rotor types are compared with each other. Especially the THD (total harmonic distortion) of output voltage is examined for the comparison.

In many cases, ferrite bonded magnets used in inner-rotor type small brushless DC (BLDC) motors do not have rotor core, and the magnetization directions of permanent magnets do not have only parallel or radial direction. In this paper, the magnetization directions of a ferrite bonded magnet are analyzed by finite element analysis for magnetization procedure. The characteristics of an inner-rotor type BLDC motor are analyzed by using the analyzed magnetization model. In the analysis, the overhang effect of the magnet is calculated by using 3-D FEM. The validity of the analysis method is verified by comparing the analyzed results with measured ones.

The isolated phase bus in power plants is used to carry large current from a generator to a power transformer. The magnetic field distribution and eddy current characteristics of a three-phase isolated phase bus have been investigated using the finite element method. This paper also describes the effects of material, thickness and radius of enclosure on the eddy current distribution.

The effects of InGaAs∕GaNAs barrier combinations were investigated in the metal organic vapor phase epitaxy grown GaInNAs quantum wells (QWs). Significant improvement was made in the optical performance of the 1.3μm range with the proposed structures. Structural investigation linked with the optical properties reveals that a thin InGaAs layer, placed between GaInNAs QWs and GaNAs layers, plays a role in redistributing the nitrogen within the QWs while maintaining a sharp interface. The amount of diffused nitrogen is proportional to the strain residing in the InGaAs layer, which explains the tendency of blueshift with the increase in GaNAs thickness.