Research And Design Of Portable Universal Optical Power Meter

As the high technology in the field of science and technology in our country, the photoelectri detection technology has been rapidly development, the demand of the optical test equipment has also increased fastly. Optical power meter is a kind of precision optical measurement instrument to detect the strength of a optical signal, widely used in optical fiber communication, optical experiment, new and high-tech fields such as biomedicine.In the field of optical fiber communication, as a measuring instrument, it is essential to test light power and light attenuation. The optical power meter, which is suitable for engineering construction site, portable, easy operation and steady performance, has great demand. However, the domestic required optical power meter mostly imported from foreign, while they have these characteristics:expensive, variously accessories, complicated operation. Although such similar products are also produced in domestic, they usually have lower performance and high prices. The photoelectric detector of a optical power meter are mainly photomultiplier, photocells and the PIN photodiode.The optical power meter using the photomultiplier need high working voltage and have great influence by environmental factors; while using photocells, the optical power meter will have a larger error affected by the dark current; in the matter of optical signal detection, the PIN photodiode not only have high precision, but also have lower influence by environmental factors.In conclusion, this paper will select the PIN photodiode as the photodetector.According to the issue, this paper will combine the basic principles of the optical power meter, and put forward a specific design scheme. Firstly, it analyzes the photoelectric conversion characteristic and the design of the photoelectric detector probe in detailed; secondly it introduces the design of the hardware circuit, including the module design such as preamplifier circuit, automatic conversion range, button control, LCD display, and power management; then it focus on the introduction of single-chip microcomputer control, software programming, serial communication. Based on the idea of modular design, the system adopts two pieces of AVR microcomputer. The ATmega88mainly used to collect the data detected from the photodetector and carry on data processing, then through the serial communication sent the result to the instrument control section, and to display by LCD panel;the ATmega64mainly used to control the LCD panel display, key input, and dual power switching function.Intention to develop the optical power meter could be generally used for different types of detectors, and for the future development of other types of optical power meter to save the cost of manpower and material resources, make it closer to the market level.The above is one of the most important feature of this paper. Finally, the established calibration and test of the developing optical power meter have meet the subject’s requirements--functional indicator and parameter indicator.