van Wim Etten

Novel Ring Resonator-Based Integrated Photonic Beamformer for Broadband Phased Array Receive Antennas—Part II: Experimental Prototype

An experimental prototype is presented that illustrates the implementation aspects and feasibility of the novel ring resonator-based optical beamformer concept that has been developed and analyzed in Part I of this paper . This concept can be used for seamless control of the reception angle in broadband wireless receivers employing a large phased array antenna (PAA). The design, fabrication, and characterization of a dedicated chip are described, in which an 8 × 1 optical beamforming network, an optical sideband filter for single-sideband suppressed carrier modulation, and a carrier re-insertion coupler for balanced optical detection are integrated. The chip was designed for satellite television reception using a broadband PAA, and was realized in a low-loss, CMOS-compatible optical waveguide technology. Tuning is performed thermo-optically, with a switching time of 1 ms. Group delay response and power response measurements show the correct operation of the OBFN and OSBF, respectively. Measurements on a complete beamformer prototype (including the electro-optical and opto-electrical conversions) demonstrate an optical sideband suppression of 25 dB, RF-to-RF delay generation up to 0.63 ns with a phase accuracy better than ¿/10 radians, and coherent combining of four RF input signals, all in a frequency range of 1-2 GHz.

Adaptive importance sampling for performance evaluation and parameter optimization of communication systems

We present new adaptive importance sampling techniques based on stochastic Newton recursions. Their applicability to the performance evaluation of communication systems is studied. Besides bit-error rate (BER) estimation, the techniques are used for system parameter optimization. Two system models that are analytically tractable are employed to demonstrate the validity of the techniques. As an application to situations that are analytically intractable and numerically intensive, the influence of crosstalk in a wavelength-division multiplexing (WDM) crossconnect is assessed. In order to consider a realistic system model, optimal setting of thresholds in the detector is carried out while estimating error rate performances. Resulting BER estimates indicate that the tolerable crosstalk levels are significantly higher than predicted in the literature. This finding has a strong impact on the design of WDM networks. Power penalties induced by the addition of channels can also be accurately predicted in short run-times.

Ethernet-based passive optical local-area networks for fiber-to-the-desk application

We introduce optical local-area network (LAN) architectures based on multimode optical fiber and components, short wavelength lasers and detectors, and the widely used fast Ethernet protocol. These architectures are designed to lower the costs associated with passive optical LAN implementation. Further reduction in overall cost is achieved through decreased network downtime, lower maintenance cost, extended geometrical spans, and larger headroom for future capacity increase. These optically transparent networks represent a novel approach for implementing fiber-to-the-desk.

Ultrafast all-optical shift register and its perspective application for optical fast packet switching

SEED (self-electrooptic effect device) configuration, symmetric-(S) SEED switching characteristics, a single all-optical memory cell, and the packet switch structure are briefly introduced. By applying a planar integrated optical circuit based on SEEDs, the demonstration of an all-optical memory cell, which can be used in optical switching and optical data storing is introduced by using master-slave integrated configuration of SEEDs. The system structure, the switching performance, and the dependence of the switching speed are discussed. Based on these performance analyzes, some improved schemes are presented. By applying a pair of external preset pulses and integration of inductors, the SEEDs devices even can provide 50 Gb/s throughput with data power of 1 mW, this is very competitive for optical communication. Based on these analyzes, an all-optical shift register that utilizes SEEDs embedded in the connecting optical waveguides is presented. Considering its advantage of application in optical packet header processing, we present the application of this all-optical shift register in an optical multiprotocol label switching switch.

Bandwidth Re-Distribution Techniques for Extended EPON Based Multi-Wavelength Networks

The broadband photonics project (BBP) under the Freehand consortium of projects looks into the design of an extended access network. The network is a photonic network which can be dynamically reconfigured to distribute bandwidth in an optimised manner. This paper presents linear programming based formulations to calculate implementation of bandwidth redistribution in the network.

Control and Management Scheme in a DWDM EPON

Passive optical networks (PONs) are a preferred architecture for distribution of bandwidth in the access network. The BSIK Freeband Broadband Photonics Project (BBP) looks at the design of a flexible DWDM PON which can be used to increase the bandwidth provided to the user. We present a control and management scheme for such a network which operates with the IEEE Ethernet passive optical network (EPON) protocol. The design emphasis is on implementing such a scheme with a cost effective and practical approach

Coherence-Multiplexed Optical RF Feeder Networks

An optical RF feeding system for wireless access is proposed, in which the radio access points are distinguished by means of coherence multiplexing (CM). CM is a rather unknown and potentially inexpensive optical code division multiple access technique, which is particularly suitable for relatively short-range applications with moderate transmission bandwidth requirements. Subcarrier multiplexing (SCM) can possibly be used on top of CM, either as single-channel or multichannel SCM. The performances of the resulting distribution networks are analyzed, incorporating the effect of chromatic dispersion, optical beat noise, shot noise, thermal noise, and-in the case of multichannel SCM-intermodulation distortion. The results of the analyses are illustrated by using numerical examples, based on the IEEE 802.11b standard for wireless LAN.

Enhanced Dynamic Range in a Directly Modulated Analog Photonic Link

We demonstrate a directly modulated analog photonic link (APL) capable of a high multioctave spurious-free dynamic range (SFDR). The APL consists of a pair of laser diodes, modulated in a push-pull manner, and a balanced photodetector aiming at suppressing the second-order intermodulation distortion (IMD2). In a wide frequency range of 600 MHz (2.60-3.20 GHz), an IMD2 suppression as high as 23 dB and an improvement of 5-18 dB of the second-order SFDR, relative to a conventional single arm photonic link, have been achieved. In this frequency range, the APL SFDR is in excess of 116 dBmiddotHz2/3 .

Coherence Multiplex System Topologies

Coherence multiplexing is a potentially inexpensive form of optical code-division multiple access, which is particularly suitable for short-range applications with moderate bandwidth requirements, such as access networks, LANs, or interconnects. Various topologies are known for constructing an optical transmission system in which several channels are coherence-multiplexed in one optical fiber. In this paper, the parallel array, the intrinsic reference ladder (IRL), and the discontinuous series system topologies will be further considered and compared with respect to code orthogonality requirements, theoretical performance, and some practical implementation aspects. A modification to the IRL system is proposed, resulting in a significant improvement in the theoretical performance.

Demonstration of IP based control and management for a reconfigurable photonic access network

An implementation of control and management for a reconfigurable photonic access network is presented. An out of band control channel is used on which an IP communication is established to communicate with remote elements. A Headend based master controller communicates with a far end embedded processor, this in turn is used to control and manage remote devices in the network.