High Normal Dispersion and Large Mode Area Photonic Quasi-Crystal Fiber Stretcher

We propose a fiber stretcher for stretching the high-energy ultrashort pulses which require high dispersion and large mode area to secure high stretching ratio and for ensuring distortionless pulses. In this line, we suggest a novel design of photonic quasi-crystal fiber (PQF) to achieve the desired high normal group velocity dispersion (GVD) of 1000 ps²/km at 1.06 μm and inner core effective mode area as 35 μm² . These unique properties have been exploited to achieve a high stretching ratio (>; 10⁵ ) as well as less nonlinearity, which, in turn, results in a distortionless fiber stretcher for an Yb-doped high-energy ultrafast fiber laser system based on chirped pulse amplification.