In this paper, we describe a detailed performance comparison of alternative single-pixel, single-mode LIDAR
architectures including (i) linear-mode APD-based direct-detection, (ii) optically-preamplified PIN receiver, (iii) PINbased
coherent-detection, and (iv) Geiger-mode single-photon-APD counting. Such a comparison is useful when
considering next-generation LIDAR on a chip, which would allow one to leverage extensive waveguide-based structures
and processing elements developed for telecom and apply them to small form-factor sensing applications. Models of
four LIDAR transmit and receive systems are described in detail, which include not only the dominant sources of
receiver noise commonly assumed in each of the four detection limits, but also additional noise terms present in realistic
implementations. These receiver models are validated through the analysis of detection statistics collected from an
experimental LIDAR testbed. The receiver is reconfigurable into four modes of operation, while transmit waveforms
and channel characteristics are held constant. The use of a diffuse hard target highlights the importance of including
speckle noise terms in the overall system analysis. All measurements are done at 1550 nm, which offers multiple system
advantages including less stringent eye safety requirements and compatibility with available telecom components,
optical amplification, and photonic integration. Ultimately, the experimentally-validated detection statistics can be used
as part of an end-to-end system model for projecting rate, range, and resolution performance limits and tradeoffs of
alternative integrated LIDAR architectures.
We describe how hyperentanglement may be used to give orders of magnitude throughput improvement over singly entangled photon pairs, for some applications. Next we demonstrate the first measurement of hyperentangled photon pairs, both of which are at telecom wavelengths, via simultaneous polarization tomography and time-bin interference measurements. Without cryogenic cooling of the nonlinear element, we measure polarization entanglement with tangle of 0.4 ± 0.2 and time bin entanglement with visibility of 83% ± 6%, both exceeding classical thresholds by approximately two standard deviations.
In this paper, we review recent developments in coherent, spectral phase encoded optical code-division multiplexed
(OCDM) systems employing integrated micro-ring resonator coding technologies and consider its application to data
confidentiality in optical networks. In addition, we discuss how such systems can be designed to be compatible with
conventional dense wavelength-division multiplexing (DWDM) networking, and review our experimental progress in
advanced modulation formats for improved spectral efficiency (up to 0.87 b/s/Hz) as well as the capability for long
transmission distances (up to 400 km).