Efficient fiber-optical interface for nanophotonic devices

Abstract

We demonstrate a method for efficient coupling of guided light from a single mode optical fiber to nanophotonic devices. Our approach makes use of single-sided conical tapered optical fibers that are evanescently coupled over the last ∼ 10 µm to a nanophotonic waveguide. By means of adiabatic mode transfer using a properly chosen taper, single-mode fiber-waveguide coupling efficiencies as high as 97(1)% are achieved. Efficient coupling is obtained for a wide range of device geometries which are either singly-clamped on a chip or attached to the fiber, demonstrating a promising approach for integrated nanophotonic circuits, quantum optical and nanoscale sensing applications.

Fiber-Coupled Diamond Quantum Nanophotonic Interface

“…In the region of physical contact between the DWT and OFT (schematically represented in Figure 2 (a)), propagating guided modes couple via their evanescent fields, forming a hybridized "supermode" [39]. Figure 2(b) displays the calculated effective indices of a DWT physically coupled to a single-ended OFT (insets display cross-sectional eigenmode profiles obtained from simulation).…”

“…As diamond nanophotonics continues to enable advances in other disciplines (including non-linear optics [34,35] and optomechanics [36,37]), the demand for scalable technology necessitates moving beyond isolated devices, to fully integrated on-chip nanophotonic networks in which waveguides route photons between optical cavities [38]. Moreover, for applications involving single photons, such as quantum nonlinear optics with diamond color centers [12,22], efficient off-chip optical coupling schemes are necessary to provide seamless transition of on-chip photons into commercial single mode optical fibers [39][40][41][42].…”

“…To efficiently couple light from our diamond nanophotonic structures, we adapt a fiber-optical interface previously developed for suspended silicon nitride nanophotonic systems [39]. Specifically, we employ a single-ended conical optical fiber taper (OFT, described in the following section) to make physical contact between the OFT tip and the on-chip freestanding DWT (Figure 1 (e)).…”

“…To minimize coupling to higher-order modes, we exploit gradual tapering which fulfills the adiabatic condition [39]:…”

Single-shot optical readout of a quantum bit using cavity quantum electrodynamics

“…At collection efficiency of 2.5% the success probability achieves a value of 0.99. This efficiency is achievable with multiple cavity structures including photonic crystals [51][52][53][54] and micro-pillars 55 , and is also within the range of single photon counters 56 . …”