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Abstract The transition towards designs which co-package electronic and photonic die together in data center switch packages has created a scaling path to Petabyte per second (Pbps) input/output (I/O) in such systems. In a co-packaged design, the scaling of bandwidth, cost, and energy will be governed by the number of optical I/O channels and the data rate per channel. While optical communication provide an opportunity to exploit wavelength division multiplexing to scale data rate, the limited 127 µm pitch of V-groove based single mode fiber arrays and the use of active alignment and bonding for their packaging present challenges to scaling the number of optical channels. Flip-chip optical couplers which allow for low loss, broadband operation and automated passive assembly represent a solution for continued scaling. In this paper, we propose a novel scheme to vertically couple between silicon based waveguides on separate chips using graded index couplers in combination with an evanescent coupler. Simulation results using a 3D finite-difference time-domain solver are presented, demonstrating coupling losses as low as 0.35 dB for a chip-to-chip gap of 11 µm; 1 dB vertical and lateral alignment tolerances of approximately 2.45 µm and ± 2.66 µm, respectively; and a possible 1 dB bandwidth of greater than 1500 nm. These results demonstrate the potential of our coupler as a universal interface in future co-packaged optics systems.
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Design of GaSb-based monolithic passive photonic devices at wavelengths above 2 µm
Abstract In this paper, we report, for the first time, a theoretical study on passive photonic devices including optical power splitters/combiners and grating couplers (GCs) operating at non-telecom wavelengths above 2 µ m in a monolithic GaSb platform. Passive components were designed to operate, in particular, at around 2.6 µ m for monolithic integration with active photonic devices on the III–V gallium antimonide material platform. The three popular types of splitters/combiners such as directional couplers, multimode interferometer-, and Y-branch-couplers were theoretically investigated. Based on our optimized design and rigorous analysis, fabrication-compatible 1 × 2 optical power splitters with less than 0.12 dB excess losses, large spectral bandwidth, and a 50:50 splitting ratio are achieved. For fiber-to-chip coupling, we also report the design of GCs with an outcoupling efficiency of ∼29% at 2.56 μ m and a 3 dB bandwidth of 80 nm. The results represent a significant step towards developing a complete functional photonic integrated circuits at mid-wave infrared wavelengths.
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- Award ID(s):
- 2144375
- PAR ID:
- 10432640
- Date Published:
- Journal Name:
- Journal of Physics: Photonics
- Volume:
- 5
- Issue:
- 3
- ISSN:
- 2515-7647
- Page Range / eLocation ID:
- 035005
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1088/2515-7647/ace509
