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Hamiltonicity is an important property in parallel and distributed computation. Existence of Hamiltonian cycle allows efficient emulation of distributed algorithms on a network wherever such algorithm exists for linear-array and ring, and can ensure deadlock freedom in some routing algorithms in hierarchical interconnection networks. Hamiltonicity can also be used for construction of independent spanning tree and leads to designing fault tolerant protocols. Optical Transpose Interconnection Systems or OTIS (also referred to as two-level swapped network) is a widely studied interconnection network topology which is popular due to high degree of scalability, regularity, modularity and package ability. Surprisingly, to our knowledge, only one strong result is known regarding Hamiltonicity of OTIS - showing that OTIS graph built of Hamiltonian base graphs are Hamiltonian. In this work we consider Hamiltonicity of OTIS networks, built on Non-Hamiltonian base and answer some important questions. First, we prove that Hamiltonicity of base graph is not a necessary condition for the OTIS to be Hamiltonian. We present an infinite family of Hamiltonian OTIS graphs composed on Non-Hamiltonian base graphs. We further show that, it is not sufficient for the base graph to have Hamiltonian path for the OTIS constructed on it to be Hamiltonian. We give constructive proof of Hamiltonicity for a large family of Butterfly-OTIS. This proof leads to an alternate efficient algorithm for independent spanning trees construction on this class of OTIS graphs. Our algorithm is linear in the number of vertices as opposed to the generalized algorithm, which is linear in the number of edges of the graph.

This article is from Sensors (Basel, Switzerland) , volume 10 . Abstract To fully utilize GaAs high drift mobility, techniques to monolithically integrate In0.53Ga0.47As p-i-n photodetectors with GaAs based optical waveguides using total internal reflection coupling are reviewed. Metal coplanar waveguides, deposited on top of the polyimide layer for the photodetector’s planarization and passivation, were then uniquely connected as a bridge between the photonics and electronics to illustrate the high-speed monitoring function. The photodetectors were efficiently implemented and imposed on the echelle grating circle for wavelength division multiplexing monitoring. In optical filtering performance, the monolithically integrated photodetector channel spacing was 2 nm over the 1,520–1,550 nm wavelength range and the pass band was 1 nm at the −1 dB level. For high-speed applications the full-width half-maximum of the temporal response and 3-dB bandwidth for the reflectively coupled waveguide photodetectors were demonstrated to be 30 ps and 11 GHz, respectively. The bit error rate performance of this integrated photodetector at 10 Gbit/s with 27-1 long pseudo-random bit sequence non-return to zero input data also showed error-free operation.

This experiment explores the use of MEMS mirrors to direct subsurface optical signals to another device and reception of those signals for use in chip to chip communications. Devices were built in PolyMUMPs to control horizontal and vertical beam direction and tilting in the outgoing signal and MEMS beam splitters for the incoming signal. Several elements of the outgoing beam path were successful and those which needed improvement indicate a high probability of success with limited trials needed and currently successful design elements could still be improved within the scope of PolyMUMPs. The incoming beam path elements were not successful as designed and would require the flip chip bonding unit now available at AFIT, or could be realized with a high probability of success and minimal design work with a more sophisticated fabrication process (such as SUMMiT).

An investigation of the use of optical communications for interconnecting AADC modules is performed. Both system and optoelectronic device studies are performed. An investigation of various light sources (primarily light emitting diodes (LEDs) and injection laser diodes) and photodetectors (silicon and germanium photodiodes (PDs), phototransistors, etc.) is performed, and the properties of these devices are analyzed. The most appropriate light emitters for near term applications are GaAsLEDs and heterostructure (or Large Optical Cavity) injection lasers for future applications. Silicon PIN photodiodes meet the present photodetectors' requirements for the AADC, or avalanche photodiodes can be used where photocurrent gain and/or larger bandwidths are required. A study of mounting techniques for the LEDs and PDs is performed with respect to the mechanical and optical properties of the devices. This investigation yielded two general configurations, on-wafer and off-wafer. Even though the on-wafer approach may result in somewhat higher speed capability, the mechanical and optical complexity involved indicates that the off-wafer mounting of the optoelectronic devices is presently a more feasible and economical approach. Various conceptual designs of optically interconnecting the AADC moudles are investigated. A candidate configuration is established where the optical path extends from the optoelectronic devices to the edge of the module via a light guide and is routed to another module via fiber optics which is located in the side panels. A theoretical analysis of the light coupling losses at the fiber/fiber interface is performed and experimental data taken.

An investigation of the use of optical communications for interconnecting AADC modules is performed. Both system and optoelectronic device studies are performed. An investigation of various light sources (primarily light emitting diodes (LEDs) and injection laser diodes) and photodetectors (silicon and germanium photodiodes (PDs), phototransistors, etc.) is performed, and the properties of these devices are analyzed. The most appropriate light emitters for near term applications are GaAsLEDs and heterostructure (or Large Optical Cavity) injection lasers for future applications. Silicon PIN photodiodes meet the present photodetectors' requirements for the AADC, or avalanche photodiodes can be used where photocurrent gain and/or larger bandwidths are required. A study of mounting techniques for the LEDs and PDs is performed with respect to the mechanical and optical properties of the devices. This investigation yielded two general configurations, on-wafer and off-wafer. Even though the on-wafer approach may result in somewhat higher speed capability, the mechanical and optical complexity involved indicates that the off-wafer mounting of the optoelectronic devices is presently a more feasible and economical approach. Various conceptual designs of optically interconnecting the AADC moudles are investigated. A candidate configuration is established where the optical path extends from the optoelectronic devices to the edge of the module via a light guide and is routed to another module via fiber optics which is located in the side panels. A theoretical analysis of the light coupling losses at the fiber/fiber interface is performed and experimental data taken.

This was a broad multi-year effort aimed at the advancement of modern optical sciences in several areas. This report summarizes solid achievement in multiple areas.

This was a broad multi-year effort aimed at the advancement of modern optical sciences in several areas. This report summarizes solid achievement in multiple areas.

This was a broad multi-year effort aimed at the advancement of modern optical sciences in several areas. This report summarizes solid achievement in multiple areas.

An optical steering device based on a substrate of PLZT ceramic has been developed. On-substrate resistors were fabricated by evaporating a less conductive metal, and the resistance was controlled by varying the length of the metal film bar that connects two adjacent electrodes. A steering ability was experimentally demonstrated, which is in agreement with both the predicted estimation and the precise computer simulation. A fast time response and good beam quality were also observed. This device can have applications in laser disk tracking and/or fine alignment of board-to-board optical interconnections. To decrease the applied voltage, this PLZT substrate with large quadratic electro-optic coefficients should be used. The steering range achieved by this design is relatively small, but it is a continuous steering. When combined with a discrete steering device such as a blazed grating, a large steering range can be achieved.

Optical interconnects are required for high speed opto-electronic packaged computing systems for fast access to large intelligent database and for fast image data processing. However, existing free space optical interconnection suffers from diffraction limitation of interconnect line density and requires many large and sophisticated beam collimation, focusing, and interconnect reconfiguration elements. It is preferred to have small interconnection beams and with large interconnection distance. Such contradictory requirement is not possible by conventional Gaussian optical beams propagating in free space. It is however possible using non-diffracting beams since the diffraction contribution of the non-diffracting beam permits the beam to propagate in free space for a substantially large distance without significant beam size broadening. In this Phase I SBIR program New Span Opto-Technology Inc. in collaboration with University of Miami demonstrated the feasibility of high-density optical interconnection based on free space non-diffracting beams. Using a diffractive beam shaper we achieved 87% efficiency. We also achieved 100 micron beam propagation of 40 cm range.