Post-Processing Trimming of Silicon Photonic Devices Using Femtosecond Laser

Abstract

Fabrication errors inevitably occur in device manufacturing owing to the limited processing accuracy of commercial silicon photonic processes. For silicon photonic devices, which are mostly processing-sensitive, their performances usually deteriorate significantly. This remains an unsolved issue for mass production, particularly for passive devices, because they cannot be adjusted once fixed in processes. This study presents a post-processing trimming method to compensate for fabrication errors by changing the cladding equivalent refractive indices of devices with femtosecond lasers. The experimental results show that the resonant wavelengths of micro-ring resonators can be regularly shifted within their free spectral range via tuning the illuminating area, focusing position, emitting power, and scanning speed of the trimming femtosecond laser with an acceptable loss increase. These experiments, as well as the trimming experiments in improving the phase balance of Mach-Zehnder interferometer switches, indicate that the femtosecond laser trimming method is an effective and fast method for silicon photonic devices.

Editorial of the Special Issue ‘Nano-Optics and Nano-Optoelectronics: Challenges and Future Trends’

“…Due to their exceptional properties, these nanostructures/nanomaterials offer a diverse range of novel applications in photodetectors [ 1 , 9 , 11 ], solar cells [ 2 , 9 , 10 ], modulators [ 1 , 3 , 8 ], light emitters [ 1 , 7 ], optoelectronic integration [ 5 , 6 ], super-resolved imaging [ 4 , 5 ], nanofabrication [ 4 ], etc. This Special Issue also encompasses the latest advancements in practical nano-optical and nano-optoelectronic technologies, such as femtosecond laser nano-processing [ 12 ], atomic layer coating [ 13 ], and new designs for photonic integration engineering [ 14 ]. It concludes with reviews that aim to offer comprehensive overviews of nano-related infrared absorption technology [ 15 ] and neuromorphic photonics devices [ 16 ], and to predict the futural trends in these nano-optic and nano-optoelectronic topics.…”

“…Another group of articles is related to nano-optical and nano-optoelectronic technologies. Wu et al [ 12 ] introduce a post-processing trimming method for compensating for fabrication errors on the silica cladding caused by an fs laser, while minimizing any impact on the core layer. The implementation of an fs laser to compensate for the phase bias in MZI electro-optic switches results in reduced power consumption during operation, so it is very efficient in optimizing nanophotonic processing.…”