Hsi-Hsir Chou

Implementation of a 6

A shutter-based free-space optical switching architecture capable of multicast transmission functionality has been proposed as a promising switching technology for storage area network applications. The main idea behind this type of switching architecture is that the system performance can be enhanced with a new electro-optical material, used for the shutters to increase switching speed. It can be distinguished from previous shutter-based optical switches which have been based on single channel to single channel switching, as we present a reconfigurable design of a 6 × 6 72-channel shutter-based optical switching core based on multimode fiber ribbon to multimode fiber ribbon switching. The design and implementation of a prototype 6 × 6 72-channel multi-mode fiber ribbon switch demonstrator utilizing a submicrosecond PLZT-based spatial light modulator as a shutter is reported. The light loss, crosstalk, and data switching characteristics of the implemented fiber ribbon switch from the evaluation tests were measured and are presented.

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In this paper, a 10-Gb/s hybrid optical fiber (OF) and free-space optics (FSO) link as part of a bidirectional long-haul OF transmission for application in outdoor environments such as bridges is proposed. A fiber-Bragg-grating (FBG) sensor head is used for monitoring the condition of a bridge, and in the case of the bridge being damaged, the transmission path is changed over from OF to the FSO link to ensure link connectivity. An Erbium-doped fiber amplifier is used to compensate for losses due to the fiber cable and the free-space channel. At a bit error rate (BER) of 10e-9, the power penalty between the OF and FSO paths is <; 1 dB, and the power variations for both paths are ±0.07 and ±0.12 dB, respectively.

6 Free-Space Optical Fiber Ribbon Switch for Storage Area Networks

A liquid crystal on silicon (LCoS) based polarization modulated image (PMI) system architecture using red-, green- and blue-based light-emitting diodes (LEDs), which offers simultaneous micro-projection and high-speed data transmission at nearly a gigabit, serving as an alternative short-range communication (SRC) approach for personal communication device (PCD) application in 5G, is proposed and experimentally demonstrated. In order to make the proposed system architecture transparent to the future possible wireless data modulation format, baseband modulation schemes such as multilevel pulse amplitude modulation (M-PAM), M-ary phase shift keying modulation (M-PSK) and M-ary quadrature amplitude modulation (M-QAM) which can be further employed by more advanced multicarrier modulation schemes (such as DMT, OFDM and CAP) were used to investigate the highest possible data transmission rate of the proposed system architecture. The results demonstrated that an aggregative data transmission rate of 892 Mb/s and 900 Mb/s at a BER of 10^(-3) can be achieved by using 16-QAM baseband modulation scheme when data transmission were performed with and without micro-projection simultaneously.

A Hybrid Optical Fiber and FSO System for Bidirectional Communications Used in Bridges

With the increasing demand for optical fiber switching technologies from data center networks, shutter-based free-space optical fiber switching technology is promising for such network applications as the major advantages of this switching technology are that multicast switching, which is a vital functionality required in data center networks, can be easily achieved through its optical fan-out mechanism and that the switching performance can also be significantly strengthened while new materials with a faster response time are used as a spatial light modulator (SLM) to act as shutters. In this paper, the characteristics of ferroelectric liquid crystals and lead lanthanum zirconate titanate EO ceramic (PLZT) materials used as an SLM to act as shutters based on a type of strips for free-space optical fiber switching technology have been investigated. Although the PLZT-based shutters have a fundamental characteristic that a higher driving voltage might be required in order to provide a fast switching time less than a subnanosecond, with the use of a simple push-pull amplifier circuit design that can make a small input signal ride on a large dc voltage, the driving of a PLZT device in an optical switch can easily be achieved. Although the power consumption problem of this PLZT device resulting from a high driving voltage was not investigated in this paper, it can be effectively improved through a general boost converter that can be used to raise a small input dc voltage to a required higher driving voltage for the PLZT device. A proof of concept 1 × N, i.e., a 1 × 6 free-space optical fiber ribbon switching architecture capable of scaling to an N × N switching architecture for data center network application, was experimentally implemented to investigate the fiber array switching properties of PLZT-based shutters based on a type of strip. The experimental results show that the bit error rates estimated from the Q-factor were all less than 10-9 and that the jitters were all less than 7.35% under a variety of shutter driving voltages at a link speed of 1 Gb/s and above.

Demonstration of micro-projection enabled short-range communication system for 5G

ABSTRACT A non-blocking optical Ethernet switching architecture with liquid crystal on a silicon-based beam-steering switch and optical output buffer strategies are proposed. For preserving service packet sequencing and fairness of routing sequence, priority and round-robin algorithms are adopted at the optical output buffer in this research. Four methods were used to implement tunable fiber delay modules for the optical output buffers to handle Ethernet packets with variable bit-rates. The results reported are based on the simulations performed to evaluate the proposed switching architecture with traffic analysis under a traffic model captured from a real-core network.

PLZT-Based Shutters for Free-Space Optical Fiber Switching

A short range visible light communication system based on the use of RGB-based LEDs which can potentially to perform multi-wavelength transmission was experimentally implemented and is presented in this paper. The performance of an equalized receiver with broadband optical filters capable of receiving multiple optical wavelengths transmitted from RGB-based LEDs was experimentally evaluated under different modulation scheme i.e. NRZ-OOK and 4-PAM. The performance degradation due to the use of broadband optical filters at the receiver has investigated and is reported.

Design and Performance Evaluation of Optical Ethernet Switching Architecture with Liquid Crystal on Silicon-Based Beam-Steering Technology

With increasing demands on storage devices in the modern communication environment, the storage area network (SAN) has evolved to provide a direct connection allowing these storage devices to be accessed efficiently. To optimize the performance of a SAN, a three-stage hybrid electronic/optical switching node architecture based on the concept of a MPLS label switching mechanism, aimed at serving as a multi-protocol label switching (MPLS) ingress label edge router (LER) for a SAN-enabled application, has been designed. New shutter-based free-space multi-channel optical switching cores are employed as the core switch fabric to solve the packet contention and switching path conflict problems. The system-level node architecture design constraints are evaluated through self-similar traffic sourced from real gigabit Ethernet network traces and storage systems. The extension performance of a SAN over a proposed WDM ring network, aimed at serving as an MPLS-enabled transport network, is also presented and demonstrated.

RGB LEDs visible light communications based on equalized receiver with broadband optical filters

This paper examines the electromagnetic interference (EMI) due to the existence of U-shape I/O ports used for connection with RJ-45 connectors. These ports result in noise when image planes are used. The investigation also provides a useful approach to potentially reduce this noise source. U-shape I/O ports are a popular printed circuit board (PCB) structure and exist on PCBs used for information technology equipment, where image planes are generally referred to conducting layers in the vicinity of the electric circuits and signal sources such as a power plane, ground plane, and chassis plane. Both numerical simulations and measurements are employed in the examination, and they exhibit useful characteristics to detect and reduce the influence of EMI on PCBs.

Free-space optoelectronic switching cores with MPLS for SANs over WDM ring networks

A micro-projection enabled short-range communication (SRC) approach using red-, green- and blue-based light-emitting diodes (RGB-LEDs) has experimentally demonstrated recently that micro-projection and high-speed data transmission can be performed simultaneously. In this research, a reconfigurable design of a polarization modulated image system based on the use of a Liquid Crystal on Silicon based Spatial Light Modulator (LCoS-based SLM) serving as a portable optical terminal capable of micro-projection and bidirectional multi-wavelength communications is proposed and experimentally demonstrated. For the proof of concept, the system performance was evaluated through a bidirectional communication link at a transmission distance over 0.65 m. In order to make the proposed communication system architecture compatible with the data modulation format of future possible wireless communication system, baseband modulation scheme, i.e., Non-Return-to-Zero On-Off-Keying (NRZ_OOK), M-ary Phase Shift Keying (M-PSK) and M-ary Quadrature Amplitude Modulation (M-QAM) were used to investigate the system transmission performance. The experimental results shown that an acceptable BER (satisfying the limitation of Forward Error Correction, FEC standard) and crosstalk can all be achieved in the bidirectional multi-wavelength communication scenario.

Analysis and Treatment of U-Shape PCB I/O Ports to Reduce the EMI From Image-Plane Noise

The electromagnetic interference (EMI) caused by the noise resulting from a common mode of stacked I/O connectors is analyzed using both numerical simulation and experimental measurements. The use of stacked connectors exists on the PCBs of today’s information technology equipment in order to reduce size; however, size reductions will cause increased severe EMI. After diagnosis and analysis, a strategy is presented to suppress the EMI noise level, as well as its emissions, and is found to be very effective as shown by our experiments.