Jun Hong

New kind of injection-locked oscillator and its corresponding long-term stability control

A new type of opto-electronic hybrid oscillator is proposed for the first time, to the best of our knowledge, and verified by experiments in this paper. Typical electronic oscillator-dielectric resonator oscillator as the first injection source is used to injection lock the first long-fiber loop-based opto-electronic oscillator (OEO); then its output is used to injection lock the second long-fiber opto-electronic oscillator. Using this method, low-phase noise output signal can be obtained. Experiments show that single side-band (SSB) phase noise of a 9.5 GHz oscillation signal at 10 kHz offset frequency decreases from -123 to -135u2009u2009dBc/Hz after the first injection, then, through the second injection, the SSB phase noise drops down to -146u2009u2009dBc/Hz. In order to solve the long-term stability problem of the above oscillator, a new stability-control circuit also is designed and verified by experiments. Experiments show that the Allan deviation decreases from 9.0×10(-11) to 2.2×10(-12) during 1 s after the long-term stability-control circuit being used.

A temperature sensor based on Fresnel reflection on a collimator

An optical sensor for temperature measurement with much higher reflected light power based on Fresnel reflection and a collimator is presented. The sensor includes only a light source, three couplers, two photodetectors and two sensing ends. One of the sensing ends is designed with a collimator which is covered by solidified epoxy resin with an oil-paper cover, and another is a fiber end with protective cladding. The measurement principle is based on relative Fresnel reflective intensity. Various ambient temperatures are measured in the experiment. The measured data is fitted to linear equation very well. Experiment is implemented by comparing the performances of the fiber-sensor and the collimator-sensor, and the latter shows a much higher reflected light power which means a high signal to noise ratio (SNR) and longer measurement distance may be gained. This is very important and useful for long distance measurement and the situation of many sensors working in parallel mode, which is sensitive to the reflected light power.

An online noise reduction method for sequential data based on Bernstein-Bezier curve formulation

Noise reduction is an important research issue for computer data processing, especially for sequential data. In recent years, owing to the fast development of computer application, the online noise reduction for the sequential data has become an increasingly important research focus. On the basis of Bernstein-Bezier curve formulation, the paper distilled its feature model and proposed a novel online curve online Bernstein-Bezier curve, OBB curve-based noise reduction method. OBB curve is a novel curve with online construction characteristics, which is easy, flexible, effective and highly extendable can be easily extended to reduce noise for n-dimensional sequential data. Experiments prove that OBB curve is a novel online curve, and the online noise reduction with the OBB curve is feasible and effective.