Abstract
A multichannel tapered coupler interfacing standard 250-μm-pitch low-numerical-aperture (NA) polarization-maintaining fiber arrays with ultradense 20-μm-pitch high-NA silicon waveguides is designed and fabricated. The coupler is based on an array of 12 dual-core glass waveguides on 250-μ m pitch that are tapered to a 20-μm pitch, simultaneously providing both pitch and spot-size conversion. At the wide end, the inner core matches the NA and mode profile of standard single-mode fiber. When drawn and tapered, the inner core "vanishes" and the outer core, surrounded by the clad, matches the NA and mode profile of the on-chip photonic waveguide. Ultradense high-efficiency coupling to an array of Si photonic waveguides is demonstrated using a 12-channel polarization-maintaining-fiber pigtailed tapered coupler. Coupling to Si waveguides is facilitated using SiON spot-size converters integrated into the Si photonic IC to provide 2-3-μm mode field diameters compatible with the tapered coupler. The tapered coupler achieves <1 dB coupling losses to photonic waveguides. Furthermore, eight-channel coupling is shown with less than -35 dB crosstalk between channels. Finally, a 640-Gb/s wavelength-division-multiplexing signal is coupled into four waveguides occupying 80μm of chip edge, providing 160-Gb/s per-channel bandwidths.
Original language | English (US) |
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Article number | 5605213 |
Pages (from-to) | 475-482 |
Number of pages | 8 |
Journal | Journal of Lightwave Technology |
Volume | 29 |
Issue number | 4 |
DOIs | |
State | Published - 2011 |
Externally published | Yes |
Keywords
- Optical fiber couplers
- Si photonics
- optical waveguides
- photonic packaging
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics