The perspective of using integrated re-sonators for non-linear and quantum optics. The figure displays a silicon ni-tride resonator ma-nufactured in our lab. Integrated WGM and ring resonators ty-pically feature a quality factor of the order of a million at 1550 nm. The quality factors of integrated resonators are indeed three orders of magnitude smaller thant those of crystalline WGMRs, Indeed, the main drawback of integrated resonators with regards to the bulk counterparts is that their Q factor is three orders of magnitude smaller. This is problematic because the threshold to trigger nonlinear interactions generally scales as a power of Q. However, the advantages granted by integrated resonators are significant enough to justify the strong interest and research activity devoted to their development.

Just to name a few, they allow for a very accurate determination of the geometrical shape of the resonator, thereby permitting a full control of its modal structure. Integrated re-sonators permit to engineer the geometrical dispersion with great flexibility and precision, a feature which is essential for example in comb generation where overall dispersion defines the shape and frequency span of optical comb spectra. And most importantly, chip-scale integration virtually opens the way to scalability, mass-production, cost-effectiveness, and ultimately, ubiquitousness for mass-market applications requiring all-optical frequency conversion. The figure displays our customized bench to couple the pump laser signal into the chipscale integrated resonator.

Further reading:
– Lin, Coillet & Chembo (2017)