US 11,808,980 B2
Ultra-compact silicon waveguide mode converter based on meta-surface structure
Hongwei Wang, Shanghai (CN); Yong Zhang, Shanghai (CN); Yu He, Shanghai (CN); Lu Sun, Shanghai (CN); and Yikai Su, Shanghai (CN)
Assigned to SHANGHAI JIAOTONG UNIVERSITY, Shanghai (CN)
Appl. No. 16/977,351
Filed by SHANGHAI JIAOTONG UNIVERSITY, Shanghai (CN)
PCT Filed Jun. 25, 2019, PCT No. PCT/CN2019/092618
§ 371(c)(1), (2) Date Sep. 1, 2020,
PCT Pub. No. WO2020/232792, PCT Pub. Date Nov. 26, 2020.
Claims priority of application No. 201910432113 (CN), filed on May 23, 2019.
Prior Publication US 2023/0103057 A1, Mar. 30, 2023
Int. Cl. G02B 6/26 (2006.01); G02B 6/42 (2006.01); G02B 6/32 (2006.01); G02B 6/34 (2006.01); G02B 6/10 (2006.01); G02B 6/14 (2006.01); G02B 6/136 (2006.01); G02B 6/12 (2006.01)
CPC G02B 6/14 (2013.01) [G02B 6/136 (2013.01); G02B 2006/12061 (2013.01); G02B 2006/12097 (2013.01); G02B 2006/12147 (2013.01); G02B 2006/12152 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A compact silicon waveguide mode converter based on a dielectric meta-surface structure of periodical oblique sub-wavelength perturbations, the compact silicon waveguide mode converter comprising a top silicon structure with oblique subwavelength perturbations etched in certain cycles with periodical length of Λ, a duty cycle and an oblique angle θ on the Silicon-on-Insulator (SOI) substrate, Λ represents the cycle of the subwavelength structure; wherein
the top silicon structure with oblique subwavelength perturbations meets the mode coupling equation:

OG Complex Work Unit Math
 wherein A and B are the amplitudes of modes A and B, and βa and βb show the propagation coefficients of the mode A and the mode B respectively; κab and κba represent the exchange coupling coefficient between waveguide modes a and b, namely the mode coupling coefficient, and κab=κba*; j represents the order of mode TEj; z represents the coordinate of the propagation direction;
wherein the mode coupling coefficient is further expressed as

OG Complex Work Unit Math
 and Eb(x, y) represent the field distribution of waveguide modes a and b under the condition of no perturbation, ω represents the switch frequency, Δε(x, y, z) represents the change of dielectric constant corresponding to the cyclic perturbation, associating with etching shape; a represents the silicon waveguide length etched in one period divided by Λ.