Lu Kecheng

Supercontinuum Generation in a Photonic Crystal Fibre

Nearly 1000-nm broad continuum from 390 nm to 1370 nm is generated in a 2-m long photonic crystal fibre. The maximum total power of supercontinuum is measured to be 60 mW with the pumping power of 800 mW output from a 200-fs Ti:sapphire laser. The evolution of the pumping light into supercontinuum is experimentally studied in detail. It is found that the mechanism for supercontinuum generation has direct relations with Raman effect and soliton effect, and the four-wave mixing plays an important role in the last phase of the supercontinuum generation.

A novel dual wavelength Er-doped fiber laser with narrow line-width

A dual wavelength narrow line-width fiber grating ring-cavity laser is reported. The output power of the two ports are up to 3.65 dBm at 1560.76 nm and 2.44 dBm at 1562.08 nm. The suppressive ratios between the two wavelengths are up to 32 dB and 40 dB respectively. Their line-widths are both 0.1 nm.

A Two-Stage S-Band Erbium-Doped Fiber Amplifier Based on W-type Erbium-Doped Fiber

An S-band erbium-doped fiber (EDF) amplifier based on a W-type EDF designed by ourselves is demonstrated by employing a two-stage double-pass configuration. The amplifier provides a bandwidth of 34 nm (1486–1520 nm) for the gain over 20 dB. The maximal gain of 32.8 dB is achieved at 1501 nm and the corresponding noise figure is 6.0 dB. The proposed amplifier has a promising foreground in extending the current network to the S band.

Special polarization properties of the internal-mirror He-Ne laser

Abstract Some special polarization phenomena of the internal-mirror He-Ne laser were observed. We obtained for the first time a linear polarization output from the internal-mirror He-Ne laser by applying radial pressure on the mirror.

Performance Improvement of Distributed and Discrete Raman Amplifiers with a Fibre Loop Mirror

We use a fibre loop mirror to reflect the residual pump power (RPP) into the fibre for solving the problems of the RPP in Raman amplifiers. The experimental results show that the novel bi-directional pumping scheme without adding extra pump lasers is effective, and higher gain and lower noise are obtained for both the distributed and the discrete Raman amplifiers.

Experimental and Numerical Analysis of a Two-Order Cascaded Raman Fibre Laser

A two-order cascaded Raman fibre laser based on GeO2-SiO2 fibre and fibre Bragg gratings is fabricated. Output power 309 mW of the second Stokes light around 1176.2 nm is obtained with a slope efficiency of 45.3%. The experimental results agree well with the simulation results obtained by using the double-pass model.

Yb3+-Doped Double-Clad Fibre Laser Pumped by Rectangular Inner Cladding

A novel Yb3+-doped double-clad silica fibre with rectangular inner cladding was designed and developed by using the modified chemical vapour deposition process, solution-doping and optical machining all together. The dimensions of the inner cladding are 100×70 µm, and Yb3+-doped concentration in the core is about 0.24 wt.%. The operation of the fibre laser pumped by inner cladding is reported. The threshold of the laser is 34 mW. When the pump power launched is 141 mW, the laser output is 84 mW at the wavelength 1075.6 nm, and the slope efficiency is 77%.

Auto-Oscillations and Chaotic Behavior in Plasma

Auto-oscillations and chaotic behavior were investigated experimentally in a plasma system produced by discharge through mixing He-Ne gases. The glow power spectra and the differential phase-space portraits show period-doubling and Ruelle-Takens routes to chaos. Periodic windows embedded in chaos and multiple subharmonic bifurcations occurring in the windows were observed.