Common Transceiver LIF⁃Lidar Based on Y⁃Type Optical Fiber for Marine Oil Spill Detection

This paper presents a novel laser⁃induced fluorescence(LIF)Lidar system for marine oil spilling detection.A bifurcated Y⁃type optical fiber and an optical collimating lens compose a coaxial configuration transceiver for this LIF⁃Lidar system.This LIF⁃Lidar system was further applied to measure the excitation spectra from floating oil slicks with different thicknesses on top of seawater at different distances.The system presents several advantages such as compact structure,stable optical path,and convenient operation,which offers a wide application prospect in ocean exploration.

NOLM-based Mode-locked Yb-doped Fiber Laser with Wide-spectrum

In this paper,a mode-locked Ytterbiumdoped fiber laser based on nonlinear optical loop mirror(NOLM)is proposed.The laser generates a wide-spectrum dissipative soliton resonance modelocked pulse with strong stimulated Raman scattering.The fiber laser is pumped forward,and the fiber ring cavity contains double-cladding Yb-doped fiber,output coupler,polarization controller,polarization independent isolator and other elements.NOLM is connected with the ring cavity by through a 3dB beam splitter and 25m single-mode fiber.The total length of the eight-shape cavity laser is about 60meters.By adjusting the intra-cavity polarization controller,a stable dissipative soliton resonance mode-locked spike pulse can be achieved.The repetition frequency of the pulse train is 3.44MHz,which is consistent with the cavity length.The 3dB bandwidth of the spectrum reaches 70.6nm,and the 10dB bandwidth is close to 147.11nm.In this experiment,dissipative soliton resonance mode-locked pulses with wide spectrum and high pulse energy are realized by a traditional modelocking method,which has wide application in many fields such as laser spectral detection and terahertz wave generation.