Comparison of an Yb-doped Fiber and a SemiconductorTaper for Amplification of Picosecond Laser Pulses

摘要

In this paper, we compare two amplifier technologies, an ytterbium-doped fiber, and a semiconductor taper,regarding their suitability to amplify sub-100 ps pulses. With both setups, we obtain amplification of the pulseenergy by more than 10 dB. However, suppression of self-lasing in the pulse intervals is critical, particularly inthe case of the semiconductor amplifier which has a very short upper state lifetime. The seed pulses were generated by a gain-switched distributed feedback (DFB) laser at arbitrary repetitionrates. They have widths of below 100 ps FWHM, pulse energies of over 100 p.j and a peak power of over 700 mW.This makes them very suitable for optical amplification. With the fiber amplifier, the pulse form remained unchanged, while with the semiconductor amplifier, itbroadened slightly. With both amplifiers, pulse peak powers of over 8 W were obtained, which represents anamplification by more than 10 dB.