Or the beauty of simplicity.

Mode engineering is a key technique for enabling nonlinear optical frequency generation in microcavities. Nonlinear Optics is progressing and growing at a fast rate thanks to very sophisticated approaches, but not only.

Optical gratings are more than one century old and with the advent of micro and nanofabrication techniques we can now fabricate not only uniform gratings but apodized, chirped and multiperiod structures for mode engineering. Sophistication often comes with the cost of a challenging fabrication technique, but Lu et al. show here how a simple but elegant approach can provide a very powerful way to obtain multi-frequency engineering functionality for nonlinear optics. The authors have termed shifted grating multiple mode splitting (SGMMS) as their new approach, where the spatial displacement of a single period grating imprinted on the inner boundary of a microring creates a rotational asymmetry that frequency splits multiple adjacent cavity modes. This approach is easy to implement and presents no additional fabrication challenges than an un-shifted grating and enables Kerr optical parametric oscillation (OPO) across a wide range of pump wavelengths in a normal-dispersion device that otherwise would not support OPO generation.

This paper by Lu et al. reports beautifully on a simple approach and obtains impressive results in a complete way, exploring both theory and experiments.

---

---

 Add Comment

You must log in to add comments.