Optical frequency combs based on ultrafast lasers have enabled numerous scientific breakthroughs. However, their use for commercial applications is limited by the complexity and cost of femtosecond laser technology. Ultrafast semiconductor lasers might change this issue as they can be mass produced in a cost-efficient way while providing large spectral coverage from a single technology. However, it has not been proven to date if ultrafast semiconductor lasers are suitable for stabilization of their carrier-envelope offset (CEO) frequency. Here we present what we believe to be the first CEO frequency stabilization of an ultrafast semiconductor disk laser (SDL). The optically pumped SDL is passively modelocked by a semiconductor saturable absorber mirror. It operates at a repetition rate of 1.8 GHz and a center wavelength of 1034 nm. The 273 fs pulses of the oscillator are amplified to an average power level of 6 W and temporally compressed down to 120 fs. A coherent octave-spanning supercontinuum spectrum is generated in a photonic crystal fiber. The CEO frequency is detected in a standard $f–\text{to}–2f$ interferometer and phase locked to an external reference by feedback applied to the current of the SDL pump diode. This proof-of-principle demonstrates that ultrafast SDLs are suitable for CEO stabilization and constitutes a key step for further developments of this comb technology expected in the coming years.

中文翻译：

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千兆赫半导体盘激光器的载波包络偏移频率稳定化

基于超快激光器的光频率梳已经实现了许多科学突破。但是，飞秒激光技术的复杂性和成本限制了它们在商业应用中的使用。超快半导体激光器可能会解决此问题，因为它们可以以经济高效的方式批量生产，同时通过一项技术即可提供大的光谱覆盖范围。但是，迄今为止，尚未证明超快半导体激光器是否适合稳定其载流子包络偏移（CEO）频率。在这里，我们介绍了我们认为是超快半导体磁盘激光器（SDL）的第一个CEO频率稳定化功能。光泵浦的SDL由半导体可饱和吸收镜被动地对接。它的重复频率为1.8 GHz，中心波长为1034 nm。振荡器的273 fs脉冲被放大到6 W的平均功率水平，并在时间上压缩至120 fs。在光子晶体光纤中会产生一个连贯的倍频程超连续谱。在标准中检测到CEO频率$F–\text{到}–\mathrm{2个}F$干涉仪，并通过施加到SDL泵二极管电流的反馈将其锁相到外部参考。该原理证明表明，超高速SDL适用于CEO稳定化，并构成了预计在未来几年中进一步发展这种梳子技术的关键一步。