Microspiral resonators for integrated photonics

Optical microspiral resonators allow for unidirectional lasing and the direct coupling of light to the device's microcavity. The microspiral cavity shape can be described as a micropillar or disk with the radius linearly depending on the azimuthal angle. The characteristic notches enables one to achieve gapless non-evanescent coupling to the microresonators, preserve high-Q resonances, and realize unidirectional lasing. It should be possible to cascade multiple double-notch-shaped microresonators to realize many element devices and possibly optical delay line, with the addition of double-notch shaped microresonators. The concept of gapless inter-cavity coupling can be extended to multi-element coupled resonators. One interesting structure is to directly couple a microspiral disk to a semicircle microdisk