Ghulam Saber

A silicon-on-insulator 120° Optical hybrid based on 3× multimode interference coupler

A 120° optical hybrid based on 3× multimode interference coupler is reported. The device exhibits less than 10° phase deviation over 55 nm in the C- and L-band.

Broadband sub-wavelength grating coupler for O-band application

We demonstrate a broadband sub-wavelength grating coupler for the O-band application, which has a simulated coupling efficiency of −3.3 dB with 3-dB bandwidth of 78 nm and a measured coupling efficiency of −4.5 dB with a 3-dB bandwidth of 65 nm for fundamental TE mode.

Compact single-etched sub-wavelength grating couplers for O-band application

We demonstrate two single-etched sub-wavelength grating coupler (SWGC) designs for O-band application, one targeting at high coupling efficiency and the other targeting at broad operating bandwidth. The high-efficiency SWGC has a measured peak coupling efficiency of -3.8 dB and a 3-dB bandwidth of 40 nm, and the broadband SWGC has a measured peak coupling efficiency of -4.3 dB and a 3-dB bandwidth of 71 nm. Focusing gratings have been used in our SWGCs to reduce the design footprints and the dimensions of our SWGCs are smaller than 45 μm × 24 μm. The back reflections of our SWGCs are suppressed to be below -15 dB over the wavelength range from 1260 nm to 1360 nm.