Auto Power Control Research Articles

Auto Power Control System from Four Different Sources

In today's fast-growing world. The energy demand is increasing with respect to time. So, our project is designed to give a continuous power supply. This project can automatically give a continuous power supply to the load. We have used four sources of supply that are Solar, Main Supply, Generator, and Inverter. These four sources are controlled by Arduino UNO ATMEGA 328pu microcontroller which provides input signals. A relay driver is used and it will sense and generate the output signal to a microcontroller and that specific relay provide a continuous power input signal. The relay will sense the amount of voltage after that it will give to a microcontroller to provide a continuous supply. In this project, we used a lamp or bulb for load demonstration purposes. Whenever primary supply fails it automatically transfer to the next available source. We have also used LCD which shows the availability of power.

InGaN based green laser diodes on semipolar GaN substrate

This paper reviews the development of the InGaN-based green laser diodes on semipolar GaN substrates, especially focusing on plane. The reduction of piezoelectric fields in InGaN quantum wells on the planes was investigated by a small blue shift in electroluminescence peaks, and high crystal quality was confirmed by clear interfaces in a transmission electron microscopy image, narrower FWHM in electroluminescence peaks, and smaller localization energy in time resolved PL results, as compared with the other planes. These physical characteristics of the leads to better laser properties: lower threshold current densities, higher output powers of over 100 mW in the spectral region beyond 530 nm, and higher wall plug efficiencies as high as 7.0–8.9% in the wavelength range of 525–532 nm, compared to those of the other planes. Estimated lifetimes were over 5000 h at 50 mW and 2000 h at 70 mW under cw operation with auto power control at a case temperature of 55 °C. The plane is the promising candidate for InGaN-based true green laser diodes.

A 12.5-Gb/s Optical Transmitter Using an Auto-power and -modulation Control

In this paper, a 12.5-Gb/s optical transmitter is implemented using 0.13-<TEX>${\mu}m$</TEX> CMOS technology. The optical transmitter that we constructed compensates temperature effects of VCSEL (Vertical cavity surface emitting laser) using auto-power control (APC) and auto-modulation control (AMC). An external monitoring photodiode (MPD) detects optical power and modulation. The proposed APC and AMC demonstrate 5<TEX>$\sim$</TEX>20-mA of bias-current control and 5<TEX>$\sim$</TEX>20-mA of modulation-current control, respectively. To enhance the bandwidth of the optical transmitter, an active feedback amplifier with negative capacitance compensation is exploited. The whole chip consumes only 140.4-mW of DC power at a single 1.8-V supply under the maximum modulation and bias currents, and occupies the area of 1280-<TEX>${\mu}m$</TEX> by 330-<TEX>${\mu}m$</TEX> excluding bonding pads.

Hybrid-integrated external-cavity laser without temperature-dependent mode hopping

We propose and demonstrate an integrated external-cavity laser (ECL) with a novel configuration designed to suppress temperature-dependent mode hopping. The laser cavity is composed of a spot-size converter integrated laser diode (SS-LD), a UV-written grating, and silicone-filled grooves on a planar lightwave circuit (PLC). The silicone is used to compensate for the difference between the temperature coefficients of the SS-LD and the silica waveguides. We calculate theoretically the temperature interval of the mode hopping in the ECL to optimize the length of the silicone-filled grooves. We fabricated test and practical lasers with the proposed configuration using PLC hybrid-integration technologies. With the test laser, we confirmed stable single-mode oscillation and a large increase in the mode-hopping temperature interval for both static and dynamic operation. We obtained a low threshold of 15 mA, an optical power of 1.0 mW at 25/spl deg/C, and an injection current of 60 mA. In the practical laser, which we additionally integrated with a front monitor photodiode, we realized auto power control with mode-hopping-free operation from 18/spl deg/C to 56/spl deg/C. These results indicate the good performance levels of our proposed laser.

Output Power Stabilization of Laser Diode Pumped Solid State Blue Light Generation.

We have developed a 473nm blue light generation source by frequency doubling using a KNbO3 for intracavity second harmonic generation of a laser diode pumped Nd:YAG 946nm laser which is combined with an auto power control system and a temperature control for the entire resonator. We tried to stabilize the output power with the results that the fluctuation is less than ±1% at 15mW of blue light under a wide environmental temperature range of 0°C and 45°C.

Preliminary aging tests on 1.5 μm band multiple-quantum-well distributed-feedback laser diodes grown by MOVPE

The letter reports the first encouraging results from preliminary aging tests of 1.5 μm band multiple-quantum-well distributed-feedback laser diodes, grown on InP grating substrate by metalorganic vapour-phase epitaxy. The devices operated stably in 50°C−5 mW−6000 h and 70°C−5 mW−4000 h autopower control accelerated aging tests.