Demonstration of an on-chip TE-pass polarizer using a silicon hybrid plasmonic grating

An on-chip, high extinction ratio transverse electric(TE)-pass polarizer using a silicon hybrid plasmonic grating is proposed and experimentally demonstrated. Utilizing plasmonics to manipulate the effective index and mode distribution, the transverse magnetic mode is reflected and absorbed, while the TE mode passes through with relatively low propagation loss. For a 6-μm-long device, the measurement result shows that the extinction ratio in the wavelength range of 1.52 to 1.58 μm varies from 24 to 33.7 dB and the insertion loss is 2.8–4.9 dB. Moreover,the structure exhibits large alignment tolerance and is compatible with silicon-on-insulator fabrication technology.

A controllable coupling structure for silicon microring resonators based on adiabatic elimination

Optical microring resonators are extensively employed in a wide range of physical studies and applications due to the resonance enhancement property.Incorporating coupling control of a microring resonator is necessary in many scenarios,but modifications are essentially added to the resonator and impair the capability of optical enhancement.Here,we propose a flexible coupling structure based on adiabatic elimination that allows low-loss active coupling control without any modifications to the resonators.The self-coupling coefficient can be monotonically or non-monotonically controllable by the proposed coupler,potentially at a high speed.The characteristic of the coupler when implemented in silicon microring resonators is investigated in detail using substantiated analytical theory and experiments.This work provides a general method in coupling control while ensuring the resonance enhancement property,making active coupling control in a resonator-waveguide system feasible.

Low-loss hybrid plasmonic TM-pass polarizer using polarization-dependent mode conversion

A low-loss hybrid plasmonic transverse magnetic(TM)-pass polarizer has been demonstrated utilizing polarization-dependent mode conversion.Taking advantage of the silicon hybrid plasmonic slot waveguide(HPSW),the unwanted transverse electric(TE)fundamental mode can be efficiently converted first to a TM higher-order mode and then suppressed by a power combiner,while the retained TM fundamental mode can pass through with negligible influence.Since the HPSW feature both strong structural asymmetry and a small interaction area in the cross-section between the metal and optical field,the optimized insertion loss of the device is as low as 0.4 d B.At the wavelength of 1550 nm,the extinction ratio is 28.3 d B with a moderate footprint of 2.38μm×10μm.For the entire C band,the average reflection of the TE mode is suppressed below-14 d B,and the extinction ratio is over 18.6 d B.This work provides another more efficient and effective approach for better on-chip polarizers.