Proc. SPIE. 9796, Selected Papers of the Photoelectronic Technology Committee Conferences held November 2015
KEYWORDS: Optical fibers, Refractive index, Digital signal processing, Optical amplifiers, Sensors, Calibration, Fiber lasers, Time metrology, Turbulence, Temperature sensors, Resistors, Pulsed laser operation, Temperature metrology
Measuring principle of time constant for thin wire thermal resistor was put forward. An 1.07μm fiber laser was used to output a rectangle laser pulse with edges of several tens microns and width of 100ms, and the thermal resistor under test was shined by the laser. As a result, the temperature of the thermal resistor rose and gradually went up to a fixed level with the irradiation. And then the thermal resistor’s temperature dropped and gradually went down to the room temperature with the laser powered off. Time constant of the thermal resistor could be obtained by means of measuring the temperature variation of the thermal resistor due to the laser pulse. A device was designed and experiments were carried out, the time constants of three commonly used thin wire thermal resistors were measured.
The objectives of this tutorial are to introduce an optical method of measuring atmospheric turbulent outer scale. The method utilizes the ratio between the correlation functions of the wandering in two perpendicular planes. A simple relationship to obtain the outer scale from the measured correlation functions is established for a particular model of turbulence, the modified Von Karman model. Base on the rational conclusion, an implementary project of measuring atmospheric turbulent outer scale with optical method is designed. At the same time, the plan of the experiment system is given. By predigesting the model, the calculating program of the measurement is written also.
A measurement system of C<sub>n</sub><sup>2</sup> based on solar power device was developed and the performance of the system was given. The continuous measurement for 24 hours on the experimental spot was taken and the curves of C<sub>n</sub><sup>2</sup> at different heights on one spot were acquired. The results of the experiments show that the system of C<sub>n</sub><sup>2</sup> based on solar power device is effective and practical for the continuous measurement in the open air，especially in no electricity and unattended circumstances.
The atmospheric refractive index structure constant is an important parameter of atmospheric turbulence intensity. It was
measured using AZZ10 micro-thermalmeter over desert where is a little or no vegetation cover. The vertical profile were
investigated by analysis of experimental data over desert with 0~30km height range. And structure characteristics of
atmospheric turbulence were given. Results can supply technological support for laser engineering applications to select
suitable testing time and time-interval.