Chen Zilun

Synchronization and Coherent Combining of Two Pulsed Fiber Ring Lasers Based on Direct Phase Modulation

We demonstrate a scalable architecture for coherent combining of pulsed fiber ring lasers based on mutual injection and direct phase modulation. By direct phase modulation in the common arm of two ring lasers, synchronous pulsed lasers can be generated and coherent combining of the two synchronous lasers is obtained. Two pulsed fiber ring lasers are coherently combined with 0.55 μJ pulse energy and 10 μs pulse duration at a repetition rate of 27.5 kHz. Experimental results show that the two fiber ring lasers are phase locked with an invariable phase difference of π and have good temporal synchronization and spatial coherence. The combining efficiency of the two pulsed fiber laser reaches 90% and the fringe contrast is larger than 40%. Neither active phase control nor polarization control is used in our experiment and this method can be extended to combine more beams and higher repetition rate scaling up to higher power.

High-Efficiency Supercontinuum Generation at 12.8 W in an All-Fiber Device

We report 12.8 W supercontinuum generation with a high optical-to-optical conversion efficiency of up to 85% in an all-fiber device. This is achieved by using an all-fiber picosecond master oscillator power amplifier laser, which has an output pigtail double clad fiber, to pump a 3-m photonic crystal fiber with the core at one end enlarged by adiabatically collapsing two inner layers of air holes while keeping other holes open. Our experimental results show that the short-wavelength generation is due to dispersive wave trapping by redshifted solitons.