High coupling efficiency, passive alignment setup for visible-range fiber-to-waveguide edge coupling

Abstract. We present a method to passively edge couple multiple optical fibers with silicon nitride waveguides in the visible wavelengths. We efficiently convert the fiber mode to the waveguide mode using an inverse taper mode size converter and support passive alignment using a U-groove that centers the optical fiber to the inverse taper. In our prototypes, we measure a coupling efficiency of −4.2  dB per facet. To reduce light leakage to the silicon substrate, we use a 6-μm oxide layer, which also eliminates the additional processes of undercutting the silicon substrate underneath the waveguide. Furthermore, the U-groove structure has a polished edge surface for coupling, reducing the steps of edge polishing the die. Fabrication of this visible-range edge coupler is complementary metal–oxide–semiconductor-compatible, making it a highly scalable method for passively packaging multiple visible-range integrated photonics devices.

[1]  Marko Loncar,et al.  Ultra-low-loss integrated visible photonics using thin-film lithium niobate , 2019, Optica.

[2]  G. Roelkens,et al.  Efficient silicon-on-insulator fiber coupler fabricated using 248-nm-deep UV lithography , 2005, IEEE Photonics Technology Letters.

[3]  Jean-Claude Tinguely,et al.  Silicon nitride waveguide platform for fluorescence microscopy of living cells. , 2017, Optics express.

[4]  Christoph K. Hitzenberger,et al.  Spectroscopic imaging with spectral domain visible light optical coherence microscopy in Alzheimer’s disease brain samples , 2017, Biomedical optics express.

[5]  S. Masmanidis,et al.  Multisite silicon neural probes with integrated silicon nitride waveguides and gratings for optogenetic applications , 2016, Scientific Reports.

[6]  R. Baets,et al.  Expanding the Silicon Photonics Portfolio With Silicon Nitride Photonic Integrated Circuits , 2017, Journal of Lightwave Technology.

[7]  K. Gardner,et al.  An optogenetic gene expression system with rapid activation and deactivation kinetics , 2013, Nature chemical biology.

[8]  Soon Thor Lim,et al.  Silicon nitride double-tip fiber-to-waveguide edge couplers at visible wavelengths , 2017, 2017 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR).

[9]  O. Hellesø,et al.  Estimation of Propagation Losses for Narrow Strip and Rib Waveguides , 2014, IEEE Photonics Technology Letters.

[10]  Xianshu Luo,et al.  Visible-light silicon nitride waveguide devices and implantable neurophotonic probes on thinned 200 mm silicon wafers. , 2019, Optics express.

[11]  Michal Lipson,et al.  Reconfigurable nanophotonic silicon probes for sub-millisecond deep-brain optical stimulation , 2018, Nature Biomedical Engineering.

[12]  L. Chrostowski,et al.  Silicon Photonics Design: From Devices to Systems , 2015 .

[13]  M. Lipson,et al.  Nanotaper for compact mode conversion. , 2003, Optics letters.

[14]  K. Deisseroth,et al.  Millisecond-timescale, genetically targeted optical control of neural activity , 2005, Nature Neuroscience.

[15]  S. Park,et al.  Fabrication method for passive alignment in polymer PLCs with U-grooves , 2005, IEEE Photonics Technology Letters.

[16]  Yidan Wang,et al.  Smartphone-controlled optogenetically engineered cells enable semiautomatic glucose homeostasis in diabetic mice , 2017, Science Translational Medicine.

[17]  Il-Joo Cho,et al.  Multifunctional multi-shank neural probe for investigating and modulating long-range neural circuits in vivo , 2019, Nature Communications.

[18]  D. Geuzebroek,et al.  [INVITED] Silicon nitride photonic integration for visible light applications , 2019, Optics & Laser Technology.

[19]  Andrei Faraon,et al.  Patterned photostimulation via visible-wavelength photonic probes for deep brain optogenetics , 2016, Neurophotonics.

[20]  G. Buzsáki,et al.  An implantable neural probe with monolithically integrated dielectric waveguide and recording electrodes for optogenetics applications , 2013, Journal of neural engineering.

[21]  Nathan C. Lin,et al.  Scanning optical coherence tomography probe for in vivo imaging and displacement measurements in the cochlea. , 2019, Biomedical optics express.

[22]  J. V. Galán,et al.  Polarization insensitive low-loss coupling technique between SOI waveguides and high mode field diameter single-mode fibers. , 2007, Optics express.

[23]  Cosimo Lacava,et al.  Coupling strategies for silicon photonics integrated chips [Invited] , 2019, Photonics Research.

[24]  Martin Schell,et al.  Polymer PLC as an optical integration bench , 2011, 2011 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference.

[25]  Matthew A. Bochenek,et al.  Alginate encapsulation as long-term immune protection of allogeneic pancreatic islet cells transplanted into the omental bursa of macaques , 2018, Nature Biomedical Engineering.

[26]  A. Zorzos,et al.  Multiwaveguide implantable probe for light delivery to sets of distributed brain targets. , 2010, Optics letters.