Polarization-independent multimode interference coupler with anisotropy-engineered bricked metamaterial

Abstract

Many applications, including optical multiplexing, switching, and detection, call for low-cost and broadband photonic devices with polarization-independent operation. While the silicon-on-insulator platform is well positioned to fulfill most of these requirements, its strong birefringence hinders the development of polarization-agnostic devices. Here we leverage the recently proposed bricked metamaterial topology to design, for the first time, to our knowledge, a polarization-independent 2 × 2 multimode interference coupler using standard 220 nm silicon thickness. Our device can be fabricated with a single etch step and is optimized for the O-band, covering a wavelength range of 160 nm with excess loss, polarization-dependent loss, and imbalance below 1 dB and phase errors of less than 5°, as demonstrated with full three-dimensional finite-difference time-domain simulations.

Y-junction beamsplitter engineered through subwavelength metamaterials

“…Tapered coupler [52] 13 150 TE0 100 (1500 -1600) < 0.07 80 (1520 -1600) < 1.50 TE1 † < 0.41 MMI [40] 35.9 100 TE0 160 (1260 -1420) < 1.00 NF NF TM0 Y-junction [18] 14 120 TE0 150 (1500 -1650) < 0.10 100 (1500 -1600) < 0.25 TM0 < 0.23 Y-junction [26] 41. The SWG-assisted symmetric Y-junction presented in this work is expected to unlock new possibilities for a myriad of applications requiring both broad bandwidth and precise power control, especially for multimode applications and/or those with multiple or cascaded power splitting stages.…”

“…[28] In addition to the demonstration of numerous devices with unprecedented performance, [10,[29][30][31][32][33] SWGs have also been successfully used to engineer different power splitters to achieve state-of-the-art performance. [34][35][36][37][38][39][40][41] As an illustrative example, ultra-broadband SWG MMIs, [36] compact polarization-independent three-guide SWG directional couplers, [32] and high-performance SWG multimode Y-junctions [42] have been demonstrated. Other alternatives include inverse design-optimized pixelated meta-structures, showing promising prospects for broadband and compact devices although they have not yet been experimentally validated.…”

A Liquid Crystal-Modulated Metastructure Sensor for Biosensing

“…Metastructures can realize many extraordinary physical properties, such as a negative refractive index, an inverse Doppler effect, etc. Using the extraordinary physical properties of metastructures, sensors, filters, and couplers [ 1 , 2 , 3 ] can be designed, as well as novel functional devices that conventional materials cannot achieve, such as perfect absorbers [ 4 , 5 , 6 ], waveguides [ 7 , 8 , 9 ], photonic crystals [ 10 ], and metalenses [ 11 , 12 ]. One of the important research directions for metastructures in the current research is to transform them from simple planar structures to three-dimensional spatial structures.…”

Triple-Band Square Split-Ring Resonator Metamaterial Absorber Design with High Effective Medium Ratio for 5G Sub-6 GHz Applications

“…The metamaterial is a sub-wavelength artificial material that exhibits unusual electromagnetic (EM) behavior, such as negative permittivity or permeability and negative or positive refractive index [ 1 ]. These properties make metamaterial-based microwave devices extremely popular for various applications such as energy harvesters [ 2 ], filters [ 3 ], sensors [ 4 , 5 , 6 , 7 ], polarization converters [ 8 ], invisible clocks [ 9 ], antenna design [ 10 , 11 , 12 , 13 , 14 , 15 ], SAR reduction [ 16 ], absorber [ 17 ], and photonic devices [ 18 , 19 , 20 , 21 ]. Metamaterial also significantly enables 5G wireless communication, which will be widely used for producing various 5G devices [ 22 ].…”