Hydrogenated amorphous silicon photonic device trimming by UV-irradiation

Abstract

A method to compensate for fabrication tolerances and to fine-tune individual photonic circuit components is inevitable for wafer-scale photonic systems even with most-advanced CMOS-fabrication tools. We report a cost-effective and highly accurate method for the permanent trimming of hydrogenated amorphous silicon photonic devices by UV-irradiation. Microring resonators and Mach-Zehnder-interferometers were utilized as photonic test devices. The MZIs were tuned forth and back over their complete free spectral range of 5.5 nm by locally trimming the two MZI-arms. The trimming range exceeds 8 nm for compact ring resonators with trimming accuracies of 20 pm. Trimming speeds of ≥ 10 GHz/s were achieved. The components did not show any substantial device degradation.

Metastable Refractive Index Manipulation in Hydrogenated Amorphous Silicon for Reconfigurable Photonics

“…Loss of hydrogen in the a‐Si:H film was reported to cause a reduction in the effective refractive index . Also, surface oxidation can reduce the effective refractive index .…”

“…Loss of hydrogen in the a-Si:H film was reported to cause a reduction in the effective refractive index. [46,47] Also, surface oxidation can reduce the effective refractive index. [13,29,48] The initial slow blue-shift can be related to oxidation of the Adv.…”

Semi-analytical model of arrayed waveguide grating in SOI using Gaussian beam approximation

“…Figures 7(b) and 7(c) illustrate the output spectrum of AWG without and with phase error (corresponding to a width variation of 25 nm). The phase error information can be used for correcting the device characteristics by postfabrication trimming process [13,14] For the given 2 μm SOI AWG, BeamPROP simulation takes nearly 35 min to complete the simulation [Intel(R) core(TM)i7-2600 CPU at 3.40 GHz processor]. AWGs with smaller footprints in 220 nm SOI, having tightly confined modes in photonic wire waveguides, can be simulated accurately by the FDTD method.…”

Compact and low-loss liquid crystal loaded Mach-Zehnder optical switch based on Si wire waveguide

“…In Si PICs, phase control is a key function for the realization of various important devices such as optical switches, modulators, variable wavelength filters, and coherent receivers [1,2,3,4,5]. It would also be a practical solution for compensating the parasitic phase-shifts stemming from structural size errors in fabricated Si photonic devices [6,7].…”