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We report the realization of efficiently coupled 3D tapered waveguide-to-fiber couplers (TWCs) based on standard lithography techniques. The 3D TWC design is capable of achieving highly efficient flat-cleaved fiber to silicon nitride photonic waveguide coupling, withT ≈ 95 % polarization-insensitive coupling efficiency, wide bandwidth, and good misalignment tolerance. Our fabricated 3D TWCs on a functional nanophotonic circuit achieveT ≈ 85% coupling efficiency. Beyond applications in high-efficiency photon coupling, the demonstrated 3D lithography technique provides a complementary approach for mode field shaping and effective refractive index engineering, potentially useful for general applications in integrated photonic circuits.
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Atomic fluorescence collection into planar photonic devices
Fluorescence collection from individual emitters plays a key role in state detection and remote entanglement generation, fundamental functionalities in many quantum platforms. Planar photonics have been demonstrated for robust and scalable addressing of trapped-ion systems, motivating consideration of similar elements for the complementary challenge of photon collection. Here, using an argument from the reciprocity principle, we show that far-field photon collection efficiency can be simply expressed in terms of the fields associated with the collection optic at the emitter position alone. We calculate collection efficiencies into ideal paraxial and fully vectorial focused Gaussian modes parameterized in terms of focal waist, and further quantify the modest enhancements possible with more general beam profiles, establishing design requirements for efficient collection. Toward practical implementation, we design, fabricate, and characterize two diffractive collection elements operating atλ = 397 nm; a forward emitting design is predicted to offer 0.25% collection efficiency into a single waveguide mode, while a more efficient reverse-emitting design offers 1.14% collection efficiency, albeit with more demanding fabrication requirements. Close agreement between simulated and measured emission for both designs indicates practicality of these collection efficiencies, and we indicate avenues to improved devices approaching the limits predicted for ideal beams. We point out a particularly simple integrated waveguide configuration for polarization-based remote entanglement generation enabled by integrated collection.
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- Award ID(s):
- 2301389
- PAR ID:
- 10568387
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optica Quantum
- Volume:
- 3
- Issue:
- 1
- ISSN:
- 2837-6714
- Format(s):
- Medium: X Size: Article No. 28
- Size(s):
- Article No. 28
- Sponsoring Org:
- National Science Foundation
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