Femtosecond laser GHz cavity lasers has enabled a new type of frequency-combs that have defined a new standard and a universal method for precisely measuring optical frequencies measuring. This quantum leap in metrology unravelled numerous technological innovations, from more precise atomic clocks to unprecedented data-transmission flowrate in telecoms. So far, frequency-combs remains table-top size and expensive, an impediment for further adoptions of this major technological break-through.
This project explored novel concept of monolithic miniaturized – matchbox size - femtosecond laser GHz cavity, in which all the optical functions are integrated in a same substrate, including active functions requiring active tuning or electro-optics effects. This concept relies mainly on femtosecond laser machining combined with some post-processing pioneered in our laboratory to fabricate this substrate and to perform the fine alignment using a femtosecond laser. In a way, ‘a femtosecond laser is used to fabricate and tune a femtosecond laser’.
We designed a monolithic lasing cavity, in which all components are mounted on a single common substrate, machined by femtosecond laser processing. The cavity design, of matchbox size, showed superior beam quality compared and performances to traditional assembly using off-the-shelf components. In parallel, we demonstrated the optical repositioning of optical components, such as mirrors for fine alignment. We are now in the process of the full integration of the system in preparation for a commercial exploitation.
