Recent advances in solid-state quantum emitters have led to the realization of quantum communication, quantum teleportation, and quantum simulations. However, to implement such quantum technologies in a practical way, it is essential to interface quantum emitters with low-loss optical platforms, such as fiber optics. So far, there have been several different approaches for coupling single-photon emissions from quantum dots into fiber optics. In particular, integrating quantum dots into nanophotonic structures can significantly enhance light extraction and produce Gaussian like far-field patterns. However, a small numerical aperture of fiber still limits single-photon coupling efficiency. Alternatively, adiabatic coupling between tapered single-photon devices and fibers can provide near-unit coupling efficiency, while the delicate tapered structures cause long-term stability problems. Therefore, none of the previous approaches have realized an efficient and reliable implementation of fiber-integrated quantum emitters. In this study, we demonstrate efficient and compact plug-and-play single-photon sources based on hole-based circular Bragg gratings. A thin-membrane planar resonator with hole gratings produces an ultra-narrow vertical beam whose emission angle matches the small numerical aperture of a single-mode fiber. Using a pick-and-place technique, the fabricated single photon devices can be precisely integrated into the core of a single-mode fiber. The integrated fiber–QD system enables the compact plug-and-play operation of single photons from a source to a detector with high coupling efficiency and long-term stability.
We demonstrated the waveguide photodetector (WG PD) integrated with spot-size converter (SSC) for coherent receiver of 100Gb/s operation. The WG PD integrated with SSC was designed as diluted WG, dual lateral taper structure, and PIN-photodiode. The epitaxial layers of InxGa1-xAsyP1-y/InP, InxGa1-xAsyP1-y, and InGaAs were adopted as the diluted WG, dual tapers, and absorber of PD, respectively. The shape and thickness of each structure were determined through the simulation of 3D finite-difference beam propagation method. Although the evanescent coupling was highly sensitive, we optimized the structures with simulated responsivity and polarization dependent loss (PDL) as 0.70 A/W and 0.1 dB, respectively. We successfully obtained the SSC-integrated WG PD through numerous fabrication process including photolithography. The electrical and optical properties were characterized with laser launching. Fabricated PDs had almost similar responsivity and PDL with the simulation results. The responsivity and PDL were measured as 0.7 A/W and less than 0.3 dB respectively. The 3 dB-bandwidth was measured as 34 GHz. We successfully realized low PDL and high responsivity by adopting the lateral taper structure for SSC-integrated WG PD.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.