KEYWORDS: Optical networks, Interfaces, Standards development, Green fluorescent protein, Prototyping, Switches, Signal processing, Local area networks, Network architectures, Internet
Work on optical network control plane protocols has enabled faster and more efficient provisioning and management of carrier core optical networks, thereby reducing operational costs and capital expenditure. Many potential data applications for such capabilities, however, require Ethernet as the physical interface into the network, rather than SONET/SDH or OTN (Optical Transport Network) interfaces. Support of such services over an optical network becomes a multi-layer networking problem, wherein the client layer is packet based (e.g., Ethernet) and the server layer is optical (SONET/SDH or OTN). This paper discusses the enhancements that have been created in SONET/SDH and OTN networks (e.g., GFP, VCAT, LCAS) for the efficient transport of Ethernet and other data networking protocols, and the related extensions to control plane protocols that are necessary to allow for the support of multi-layer networking. Different control-plane models are being pursued in standards bodies such as ITU-T and IETF, and prototyping is being carried out and tested in the OIF. These various approaches are discussed in detail here, with focus placed on the prototyping work that has been done in the OIF, especially for the OIF 2005 Interoperability Demonstration.
Feasibility of photonics in beam forming and steering of large phased-array antennas onboard communications satellite/avionics systems is addressed in this paper. Specifically, a proof-of-concept demonstration of phased- array antenna feed network using fiber optic true time-delay (TTD) elements is reported for SATCOM phased-array antennas operating at C-band. Results of the photonic hardware design and performance analysis, including the measured radiation patterns of the antenna array fed by the photonic BFN, are presented. An excellent agreement between the analysis and measured data has been observed. In addition to being light- weight and compact, several unique characteristics such as rf carrier frequency agility and continuous steerability of the radiated beam achieved by the fiber optic TTD architecture are clear evidences of its superiority over other competing photonic architectures.
This paper describes the development of a prototype onboard baseband switch for use in advanced satcom systems. The modular switch is designed to accommodate different types of satcom services and/or carriers. The selected architecture utilizes a high-speed fiber optic ring for the I/O interconnections of the satcom channels handling both circuit- and packet-type traffic. Whereas, an optical star topology is used for onboard clock distribution. The onboard baseband switch design makes maximum use of photonics, VLSI, and standard cell/gate array technologies to implement the hardware/firmware required for a power-efficient, light-weight, reliable payload with a flexible switch architecture. Relevant optical technologies, active and passive components, and systems considerations to ensure a high reliability operation are discussed. To assess its viability in potential commercial applications, the state-of-the-art of photonics technology and future prospects for economical large capacity multi-channel services are briefly reviewed.
Two optical beam forming network (BFN) architectures that are deemed viable for on-board satellite phased-array antenna applications are assessed for functional capacity and technology feasibility: specifically, the implementation issues, reliability, and long-term performance are discussed for an M-beam, N-element phased-array antenna operating at Ka-band. Also included are the results of recently demonstrated proof-of-concept BFNs employing fiber optic true-time delay elements and coherent optical processor (COP) based approaches. The details of the trade-off study results and relevant POC hardware developed will be presented in the conference to demonstrate the advantage of light weight and large bandwidth capability of photonic beamforming which are at premium in large antenna arrays. Coherent optical processor using Fourier transform has many advantages.
Application of photonics in beam forming and steering for phased-array antennas is addressed in this paper. Several photonic beam forming and steering network (BFN) architectures are assessed for their capability and technology feasibility, including the mass, prime power, and volume of the payload feeding a multibeam multi-element phased-array antenna. Trade-off issues in BFN architecture and technology selection processes and critical long lead time technical areas that must be developed before its successful deployment on-board communications satellite have been identified. Results of already demonstrated proof-of-concept schemes are also presented.
Feasibility of space-fed optical beam forming networks for use on board satellite C-band multi-beam phased-array antennas is addressed in this paper. Two optical space-fed BFN architectures have been investigated: one using optical fibers as delay lines to simulate the required microwave phase shifts at the feed array elements and the other formed by reducing the microwave BFN to optical dimensions and then converting, in a 1:1 correspondence, the optical phase shifts to the microwave equivalent. BFN system design, trade-off and performance are evaluated for payload weight, size and power requirements.
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