Compact eightchannel wavelength demultiplexer using modified photonic crystal ring resonators for CWDM applications An eightchannel wavelength demultiplexer by cascading of ring resonators (RRs) in photonic crystal (PhC) structure is proposed in this paper. In designing of this demultiplexer, we used eight squareshaped PhC RRs with different refractive index (RI) of defect rods to generate a distinctive resonance wavelength. Each PhC RR has a specific resonance wavelength with tuning a variety of design parameters such as RI of a whole, defect and inner rods and radius of defect rods. In operating wavelength of xcexbb0xe2x80x89xe2x80x891497xc2xa0nm, the transmission power and quality factor (Q) of single RR are discovered as 96% and 1000, respectively. The average power transmission, channel spacing, crosstalk and full width at half maximum are found by finite difference time domain method to be about 96xe2x80x89xc2xb1xe2x80x891%, 2.25xc2xa0nm, xe2x88x92xe2x80x8935xc2xa0dB and 1.5xc2xa0nm, respectively. Simulation outcomes demonstrate that the designed demultiplexer has a proper operation. The footprint of the designed device is aboutxe2x80x89xe2x80x89115xc2xa0xcexbcm2, which makes this device a promising for future photonic integrated circuits.

MultiParameter Sensing in a Multimode SelfInterference MicroRing Resonator by Machine Learning A universal multiparameter sensing scheme based on a selfinterference microring resonator (SIMRR) is proposed. Benefit from the special intensity sensing mechanism, the SIMRR allows multimode sensing in a wide range of wavelengths but immune from frequency noise. To process the multiple mode spectra that are dependent on multiple parameters, we adopt the machine learning algorithm instead of massive asymptotic solutions of resonators. Employing the proposed multimode sensing approach, a twoparameter SIMRR sensor is designed. Assuming that two gases have different wavelength dependence of refractive indices, the feasibility and effectiveness of the twoparameter sensing strategy are verified numerically. Moreover, the dependence of parameter estimation accuracy on the laser intensity noises is also investigated. The numerical results indicate that our scheme of multiparameter sensing in a multimode SIMRR holds great potential for practical highsensitive sensing platforms compared with the singlemode sensing based on whispering gallery mode (WGM) resonators.