Qinglin Kong’s scientific contributions

The stability and reliability of sensors significantly influence the quality of the ocean buoy data. The long-time submersion of sensors increases the risk of biofouling, leading to a decline in data quality and malfunctions. To resolve this problem, this paper presents an automatic seawater sampling and drainage system based on the formation principles and characteristics of biofilms. The sensor is exposed to seawater only during the measurement cycle, minimizing the contact time with seawater. This disrupts the conditions for the formation and growth of marine microorganisms. A comparative experiment was conducted at a shore station by using different methods, and the measurement data were analyzed. The study demonstrated the applicability and efficiency of the proposed method compared to traditional methods in measuring temperature, salinity, and chlorophyll. In conclusion, we point out the disadvantages of the method and emphasize future research.

A photonic crystal fiber (PCF) with sub-wavelength air inner core and Ge-doped concentric ring outer core is proposed. The full vector finite element method with perfectly matched layer is used for simulation. Mode crossing phenomenon which can be controlled through the hollow core diameter is investigated. A PCF with an effective compensated dispersion range of ±1.38 ps/nm/km from 1460 nm to 1637 nm wavelength is designed. The dispersion compensating PCF (DCPCF) can compensate for the dispersion and dispersion slope of a standard single mode fiber (SMF) at the same time. The kappa value matches very well with that of the commercial single mode fiber. Moreover, the figure of merits inside air core region of the proposed DCPCF is improved by 21.3 dB at 1550 nm wavelength compared to a hollow core photonic bandgap (PBG) fiber. This field enhancement can effectively reduce the material loss and the nonlinear accumulation in dispersion compensation fibers.

A simple photonic crystal fiber (PCF) structure with silicon nanocrystals (Si-nc) embedded in core is proposed. The influence of geometric parameters is numerically investigated and three high numerical aperture PCFs for optical coherence tomography are designed. The zero dispersion wavelengths are at 0.83 μm, 1.06 μm and 1.31 μm wavelengths which are used for ophthalmology, dermatology and dentistry, respectively. By introducing a circular rod composed of Si-nc in the center of core region, the numerical apertures are greatly improved, which are 0.61 at 0.83 μm wavelength, 0.65 at 1.06 μm wavelength and 0.66 at 1.31 μm wavelength, respectively. The transverse resolutions as high as 0.463 μm, 0.563 μm and 0.682 μm are obtained correspondingly. Moreover, the confinement losses are as low as 4.5 × 10⁻⁸ dB/km at 0.83 μm wavelength for PCF1, 3.8 × 10⁻⁷ dB/km at 1.06 μm wavelength for PCF2, 2.2 × 10⁻⁶ dB/km at 1.31 μm wavelength for PCF3, respectively.