The transfer of phase coherence from an ultrastable master laser to a distributed feedback diode laser, using an optical comb as a transfer oscillator, is obtained via a new scheme allowing continuous scanning across the whole tuning range of the slave laser together with absolute frequency determination. This is accomplished without phase lock loops, through a robust high-bandwidth feed-forward control acting directly on the slave laser output radiation. The correction is obtained by means of a dual-parallel Mach–Zehnder interferometer used as an optical single-sideband modulator. Coherence transfer across a master–slave frequency gap of 14 THz yields an ∼10 kHz linewidth providing high injection efficiency of an optical cavity with finesse 250 000. This allows demonstrating a cavity ring-down absorption spectrum of low-pressure ambient air over a 300 GHz spectral window.

中文翻译：

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前馈梳状辅助相干转移到可广泛调谐的DFB二极管激光器

通过一种新的方案可以实现相干从超稳定的主激光器到分布式反馈二极管激光器的相干转移，该方案使用光学梳作为传输振荡器，该方案允许在从属激光器的整个调谐范围内进行连续扫描，并确定绝对频率。通过直接作用于从激光器输出辐射的稳健的高带宽前馈控制，可以在没有锁相环的情况下完成此任务。通过用作光单边带调制器的双并联马赫曾德尔干涉仪获得校正。在14 THz的主从频率间隙上的相干传递产生〜10 kHz的线宽，从而为具有25万细度的光腔提供了高注入效率。