By employing the enhanced phase transfer of single microring resonator, the enhanced intensity sensing is obtained
based on the dual microring resonator with coupled mode theory. The two times higher sensitivity than the conventional
microring sensor is demonstrated based on the FDTD simulation.
In recent years, silicon nanophotonic devices have attracted more and more attention due to their compactness, low power consumption, and easy integration with other functions. In addition to the higher index of silicon material providing stronger light confinement, the optical resonance associated with the novel structure design also enhances the performance of nanophotonic devices and offers stronger light-matter interaction. Silicon nanophotonic devices such as polarization beamsplitters, mirrors and reflectors, slow light waveguides, and microring sensors are studied, and all of them demonstrate much better performances due to the incorporated optical resonance enhancement.
The area of integrated optical circuits has been undergoing rapid development and gaining a great deal of applications in
fiber communications and optical interconnections. These applications bring a significant challenge to optical circuits
such as increased circuit density and further miniaturized devices. Compact and high performance optical components
are in great demand. This paper present our proposal to use Si based compact diffractive components for coupling,
splitting, and reflection in integrated optical circuits. First, a novel subwavelength grating, binary blazed grating (BBG),
is used as a high efficient vertical coupler from single mode fiber to Si waveguide. By using the strong polarization
dependence of the BBG coupler, a polarization beam splitter (PBS) is proposed to split the polarizations of input light
from fiber into two waveguides separately, during the coupling process. The coupling length is merely 14 μm. The
extinction ratio is better than 20 dB for both polarizations over a 40 nm wavelength range and the coupling efficiencies
for two polarizations are 58% and 50%, respectively. Second, a broadband and high efficient mirror based on the BBG is
designed and fabricated. Up to 96% reflectivity over a wavelength rang of 1.2~1.7um was achieved both theoretically
and experimentally. Finally, a nanoscale pillar waveguide is proposed as an ultra small nanotaper for mode conversion
between fiber and submicron waveguide. It has been demonstrated that a 13 μm long taper is able to convert a mode size
of 4 μm into 1 μm with an efficiency of 85%.