Low noise frequency combs and their use in broadly tunable lasers and optical coherence tomography

Licentiatavhandling, 2022

Frequency combs revolutionized the world of laser physics by providing a link between the microwave and optical domains. Such a link allows for precise knowledge of any comb line’s absolute average location, as well as the average spacing between any two comb lines. Here, we exploit this knowledge for a variety of applications, and study the limits thereof. Combs from a variety of sources are studied, and in all cases, low noise and/or highly mutually coherent tones can be readily produced which are useful in a variety of contexts.

More specifically, the phase/frequency noise of comb tones is inves- tigated, along with the mutual coherence between two comb lines. In addition, the relative intensity noise of a full comb spectra and of individual comb lines is also investigated.

The low phase/frequency noise of individual comb lines as produced in electro-optic and in normal dispersion photonic molecules is used for the generation of highly tunable and low noise laser sources, and the high mutual coherence and precise repetition rate of an anomalous dispersion microresonator combs is used for optical coherence tomography.