Low-loss and fabrication tolerant silicon mode-order converters based on novel compact tapers

Abstract

We propose large bandwidth and high fabrication-tolerance mode-order converters on the silicon-on-insulator platform based on novel compact tapers structures. Each of the converters is in a single waveguide. Designs of different symmetries with and without breaking the parities between odd and even modes are illustrated. The fabrication tolerances of the devices are also investigated. The simulation results show that high conversion efficiencies can be readily achieved over a wavelength range from 1520 nm to 1580 nm for all of the proposed devices. The average conversion efficiencies of TE1-to-TE0, TE2-to-TE0, TE3-to-TE0, TE2-to-TE1, TE3-to-TE1, and TE3-to-TE2 converters are -0.061 dB, -0.052 dB, -0.11 dB, -0.119 dB, -0.168 dB, and -0.154 dB, respectively. The conversion efficiencies have negligible degradations under normal width and thickness deviations.

Acoustic one-way mode conversion and transmission by sonic crystal waveguides

“…In addition, it can be inferred that an effective one-way mode-conversion from even type to odd type can also be realized by our proposed structure. Such an even-odd mode conversion has been extensively investigated in integrated optics, because it plays a very important 7 role in increasing transmission capacity by carrying information on different modes with only a single wavelength carrier [59][60][61][62][63][64] . This mode conversion concept can be used in many applications such as subwavelength edge detection 65 , cavity biosensors 66 , and direction selective structures 67 .…”

Ultra Broadband Mid-Infrared Ge-on-Sipolarization Rotator

“…Directional couplers, however, are inherently narrow-band and fabrication sensitive structures. To allow broadband conversion over the 8-11 µm wavelength range the TE1 to TE0 mode converters proposed by D.Chen et al were utilized [7]. This approach is based on using an asymmetric taper structure so that it provides the anti-phase components of the TE1 mode different effective path lengths so that both components become in-phase and a TE0 mode is generated at the output.…”

Dielectric Nanoaperture Metasurfaces in Silicon Waveguides for Efficient and Broadband Mode Conversion with an Ultrasmall Footprint

“…According to the coupled‐mode theory, [ 10,11 ] efficient mode conversions require satisfying the phase‐matching and field‐overlapping conditions that determine the maximum efficiency and the propagation distance for the maximum conversion, respectively. Conventional schemes for MOCs include Mach‐Zehnder interferometer, [ 12 ] directional coupler, [ 13,14 ] computation‐designed waveguide, [ 15 ] topology optimized photonic‐crystal waveguide, [ 16 ] taper‐structure waveguide, [ 17 ] and cascaded trenches etched inside silicon nanowires. [ 18 ] However, these schemes typically require large footprints and have limited operation bandwidth of only several tens of nanometers.…”