Jerzy Zielinski

Data transmission optical link for LLRF TESLA project part II: application for BER measurements

It may be predicted now, even assuming a very conservative approach, that the next generation of the Low Level RF control systems for future accelerators will use extensively such technologies like: very fast programmable circuits equipped with DSP, embedded PC and optical communication I/O functionalities, as well as multi-gigabit optical transmission of measurement data and control signals.

FPGA and optical network based LLRF distributed control system for TESLA-XFEL Linear Accelerator

The work presents a structural and functional model of a distributed low level radio frequency (LLRF) control system for the TESLA-XFEL accelerator. The design of a system basing on the FPGA chips and multi-gigabit optical network was debated. The system design approach was fully parametric. The major emphasis is put on the methods of the functional and hardware concentration to use fully both: a very big transmission capacity of the optical fiber telemetric channels and very big processing power of the latest series of the, DSP enhanced and optical I/O equipped, FPGA chips. The subject of the work is the design of a universal, laboratory module of the LLRF sub-system. Initial parameters of the system model under the design are presented.

Data transmission optical link for LLRF TESLA project part I: hardware structure of OPT0 module

It may be predicted now, even assuming a very conservative approach, that the next generation of the Low Level RF control systems for future accelerators will use extensively such technologies like: very fast programmable circuits equipped with DSP, embedded PC and optical communication I/O functionalities, as well as multi-gigabit optical transmission of measurement data and control signals. The paper presents the idea and realization of a gigabit synchronous data distributor designed to work in the LLRF control system of TESLA technology based X-ray FEL. The design bases on a relatively simple and cheap FPGA chip Cyclone. Commercially available SERDES (serializer/deserializer) and optical transceiver chips were applied. The optoelectronic module is embedded on the main LLRF BMB (backbone mother board). The MB provides communication with the outside computer control system, programmable chip configuration, integration with other functional modules and power supply. The hardware implementation is here described and the used software for BER (bit-error-rate) testing of the multi-gigabit optical link. The measurement results are presented. The appendix contains a comparison between the available protocols of serial data transmission for FPGA technology. This paper is a partial contribution to the next version of the SIMCON system which is expected to be released this year. The SIMCON, ver 3.0 will contain 8 channels and multi-gigabit optical transmission capability. It will be a fully modular construction.

Synchronous optical transmission data link integrated with FPGA for TESLA FEL SIMCON system: long data vector optical transceiver module tests

The X-ray free-electron laser X-FEL that is being planned at the DESY research center in cooperation with European partners will produce high-intensity ultra-short X-ray flashes with the properties of laser light. This new light source, which can only be described in terms of superlatives, will open up a whole range of new possibilities for the natural sciences. It could also offer very promising opportunities for industrial users. SIMCON (SIMulator and CONtroller) is the project of the fast, low latency digital controller dedicated to the LLRF system in VUV FEL experiment. The main purpose of the project is to create a controller to stabilize the vector sum of fields in cavities of one cryo-module in the experiment. The device can be also used as the simulator of the cavity and test bench for other devices. The synchronic, optical link project was made for the accelerator X-FEL laser TESLA, the LLRF control system experiment at DESY, Hamburg. The control and diagnostic data is transmitted up to 2.5Gbit/s through a plastic fiber in a distance up to a few hundred meters. The link is synchronized once after power up, and never resynchronized when data is transmitted with maximum speed. The one way link bit error rate is less then 10-15. The transceiver component written in VHDL that works in the dedicated Altera® Stratix® GX FPGA circuit. During the work in the PERG laboratory a 2.5Gbit/s serial link with the long vector parallel interface transceiver was created. Long-Data-Vector transceiver transmits 16bit vector each 8ns with 120ns latency.

Data transmission optical link for RF-GUN project

Today, the fast optical data transmission is one of the fundamentals of modern distributed control systems. The fibers are widely use as multi-gigabit data stream medium. For a short range transmission, the multimode fibers are in common use. The data rate for this kind of transmission exceeds 10 Gbps for 10 Gigabit Ethernet and 10G Fibre Channel protocols. The Field Programmable Gate Arrays are one of the opportunities of managing the optical transmission. This article is concerning a synchronous optical transmission system via a multimode fiber. The transmission is controlled by the FPGA of two manufacturers: Xilinx and Altera. This paper contains the newest technology overview and market device parameters. It also describes a board for the optical transmission, technical details of the transmission and optical transmission results.