Cascaded Microring Resonators Research Articles

Highly-sensitive sensor with large measurement range realized with two cascaded-microring resonators

A highly-sensitive sensor consisting of two cascaded-microring resonators (MRR) is suggested and investigated theoretically. The two MRRs are based on nanoslot waveguides and Si nanowires. By appropriately choosing the parameters, the MRR-based on nanoslot waveguides has a high sensitivity. The other MRR-based on Si nanowires is designed to have a large free spectral range (about 38 nm) and consequently a large measurement range (though its sensitivity is low). In this way, a highly-sensitive sensor with a large measurement range is achieved theoretically from the output spectral response from the bus waveguide of the two cascaded-MRRs. In order to make the design flexible and compact and reduce the crosstalk, the two drop waveguides for the cascaded-MRRs are perpendicular to the horizontal input bus waveguide.

All-optical format conversions from NRZ to BPSK and QPSK based on nonlinear responses in silicon microring resonators

We propose and numerically verify a novel scheme of all-optical format conversion from non-return-to-zero (NRZ) to binary phase-shift- keying (BPSK) at 160 Gb/s using cascaded microring resonators (CMRR) on a single silicon chip. The conversion is based on large phase shift and flattened intensity-response characteristics in the CMRR. A continuous-wave light experiences different phase shifts controlled by the power of an input NRZ signal with an ~8.8-dB extinction ratio, while maintaining approximately the constant intensity. All-optical format conversion from NRZ to quadrature phase-shift-keying (QPSK) is also demonstrated based on parallel NRZ/BPSK converters in a Mach-Zehnder interferometer structure.