An optical structure comprising an optical resonator is provided. The
optical resonator comprises a first set of nested closed optical regions,
forming a distributed feedback resonator structure with a direction of
radially alternating optical refractive index, and a second set of nested
optical regions, forming a distributed feedback resonator structure with
a direction of radially alternating optical refractive index. Each
optical region of the second set is interrupted by a first gap region
with a lower refractive index, wherein the first gap regions
substantially overlap in the direction of radially alternating optical
refractive index. The first set is arranged nested within the second set
and the optical structure further comprises a first optical waveguide
optically coupled to the optical resonator via a first waveguide portion
reaching into the first gap regions and being arranged coplanar to the
optical resonator.