Ion Implantation of Germanium Into Silicon for Critical Coupling Control of Racetrack Resonators

Ali Zarrar Khokhar; Milan M. Milosevic; Xingshi Yu; Graham T. Reed

Abstract:

Abstract—Critical coupling control is an important concept usedin integrated photonics to obtain functionalities such as singleand coupled resonator optical filters and wavelength multiplex-ers. Realization of critical coupling depends strongly on devicefabrication, and reproducibility is therefore an ongoing challenge.Post-fabrication trimming offers a solution for achieving optimalperformance for individual devices. Ion implantation into siliconcauses crystalline lattice damage which results in an increase ofthe material’s refractive index and therefore creates a platformfor realization of various optical devices. In recent years, we havepresented results on the development of erasable gratings, opticalfilters and Mach–Zehnder interferometers using ion implantationof germanium into silicon. Here, we report the design, fabricationand testing of silicon-on-insulator racetrack resonators, trimmedby localised annealing of germanium ion implanted silicon usingcontinuous and pulsed wave laser sources. The results demon-strate the ability to permanently tune the critical coupling con-dition of racetrack resonators. Compared to the pulsed lasersused for annealing, continuous wave lasers revealed much higherextinction ratio due to improved material quality after siliconrecrystallization.

research from:

• Foundation University - Faculty of Engineering and IT

Year:

2020

Type of Publication:

Article

Journal:

Journal of Lightwave Technology

Volume:

38

Number:

7

Pages:

1865-1873

Month:

4

DOI:

10.1109/JLT.2020.2967935