Session Index

"We review the application of subwavelength engineering in the design of waveguide grating couplers [1-6] and describe some of our recent work on dual-band waveguide grating couplers [7] and small-footprint perfectly vertical grating couplers for waveguide to multicore fiber interfacing[8]. References 1. X. Chen and H.K. Tsang: ""Nanoholes Grating Couplers for Coupling Between Silicon-on-Insulator Waveguides and Optical Fibers,"" IEEE Photonics Journal, 1, 184-190, 2009. 2. X. Chen, C. Li and H. K. Tsang, ""Two dimensional silicon waveguide chirped grating couplers for vertical optical fibers,"" Optics Communications 283, 2146-2149, 2010 3. X.Chen and H.K.Tsang, ""Polarization-independent grating couplers for silicon-on-insulator nanophotonic waveguides,"" Optics Letters, 36, 796-798, 2011 4. X. Chen, K. Xu, Z. Cheng, C. K.Y. Fung and H.K. Tsang, ""Wideband subwavelength gratings for coupling between silicon-on-insulator waveguides and optical fibers,"" Optics Letters, 37, 3483-3485, 2012. 5. Z.Z. Cheng, Z. Li, K. Xu and H.K.Tsang, ""Increase of the grating coupler bandwidth with a graphene overlay,"" Appl. Phys. Lett. 104 111109, 2014 6. Zhenzhou Cheng, Xia Chen, Chi Yan Wong, Ke Xu, and Hon Ki Tsang, ""Broadband focusing grating couplers for suspended-membrane waveguides,"" Opt. Lett. 37, 5181-5183, 2012 7. Wen Zhou, Zhenzhou Cheng, Xiankai Sun, and Hon Ki Tsang, ""Tailorable dual-wavelength-band coupling in a transverse-electric-mode focusing subwavelength grating coupler,"" Opt. Lett. 43, 2985-2988, 2018. 8. Yeyu TONG, Wen Zhou and Hon Ki Tsang, “Efficient Perfectly Vertical Grating Coupler for Multi-Core Fibers Fabricated with 193-nm DUV Lithography,” accepted for Optics Letters 2018. "

 

Based on adiabatic elimination concept, we experimentally demonstrate that the behavior of silicon cladding-modulated waveguide gratings strongly depends on the surrounding cladding material due to its different mode coupling phenomenon.

 

We propose and demonstrate a silicon-on-insulator (SOI) based 4x4 mode-division multiplexer (MUX) and de-multiplexer (DEMUX) using asymmetric directional couplers. Input signal from the fundamental mode can be converted to higher order modes and vice versa. Simulation and experiment are performed.

 

We demonstrated a fiber-wireless 2×2 MIMO system using LP00 and LP01 mode division multiplexing. The proposed system can reach the data rate 52.58-Gb/s for a 60GHz wireless system with 5-km FMF and 3-m air link.

 

Forward bias operation of high-speed silicon optical MZM increases radio-frequency link gain over 30dB and offers improvement of RF linking gain from DC to 25GHz ranges from 30dB to 13dB when compared to reverse bias operation (-8V). Comparable SFDR around 104.5 dB Hz2/3 is also observed.

 

We have successfully demonstrated the optical power scaling in the 2x4 GaN-based mirco-Light-Emitting Diode (u-LED) arrays with optical modulation bandwidths up to 574 MHz and output power up to 6.68 mW, and a 700 Mbps data rate was achieved.