TECHNICAL DOCUMENT. Design Specifications for the Antares Optical DAQ-DWDM Network Part I Passive Optical Network. see also:

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1 NIK HEF NATIONAL INSTITUTE FOR NUCLEAR AND HIGH ENERGY PHYSICS ETR TECHNICAL DOCUMENT Design Specifications for the Antares Optical DAQ-DWDM Network Part I Passive Optical Network see also: Part II: Optical/Electrical & Electronics ETR , Part III: Installation, Production and Test Procedures ETR (*) Part IV: Form Factors and Miscellaneous Mechanics ETR (*) Jelle Hogenbirk, Paul Rewiersma 5.0 Abstract: This document presents the design and design specifications of the DWDM passive optical network in Antares for the DAQ and Slow Control. The optical network is carefully calculated in terms of optical losses, wavelengths and components. It is coherent with the system optical margin. Not approved components, value change or components added, like extra splices etc. anywhere in this optical network will disturb correct operation of the entire DWDM optical network (*) expected January 2001 January 2001 jelle@nikhef.nl NIKHEF, DEPARTMENT OF ELECTRONIC TECHNOLOGY P.O.box 41882, NL 1009 DB AMSTERDAM

2 DWDM Electronics 2/14 Copyright NIKHEF, Amsterdam November 2000 Literary and scientific copyright reserved in all countries of the world. This report, or any part of it, may not be reprinted or translated without the written permission of the Director of NIKHEF. However, permission will be freely granted for appropriate non-commercial use. If any patentable invention or registrable design is described in this report, NIKHEF makes claim to property rights. NIKHEF will oppose any attempt by a user to claim any propriety or patent rights in such inventions or designs as may be described in the present document. P.O. Box DB Amsterdam Kruislaan SJ Amsterdam Phone +31-(020) Fax +31-(020) The Netherlands

3 DWDM Electronics 3/14 Table of Contents List of Abbreviations...3 Introduction...4 Basic Optical Network Design...4 DWDM Channel Distribution...5 Calculated Optical Loss Table...7 Optical System Power Budget/Margin...7 Polarization Dependent Loss...8 Polarization Mode Dispersion....8 Active Opto-Electrical conversion...8 Passive Optical Parts...8 Optical Circuit tolerances...8 Circuit Simulations...9 References...9 List of Abbreviations ARS DWDM EMC IC ITU JB M SC SMF 28 SCM SWBC O/E or E/O PM PSC Asynchronous Ring Sampler Dense Wavelength Division Multiplexer Electrical Mechanical Cable Gigabit Ethernet Interconnect Cable International Telecommunication Union Junction Box Local Control Module Master Local Control Module Slow Control (detector control) Corning Standard fiber String Control Module Single Window Broadband Coupler Optical-Electrical or Electrical-Optical Photomultiplier Alcatel's Pure Silica Core fiber

4 DWDM Electronics 4/14 Introduction A Sector of the Antares detector consists of 4 s and 1 M, each having 3 Photo- Multipliers with matching electronics. A String has 6 Sectors. The final detector will have 10 Strings. The PM signals are digitized in the containers using a full custom ASIC (ARS1). The average PM count rate is 60 khz. Most of the PM counts are from bioluminescence and potassium 40 and not correlated to an event. A real event is expected to be only one per week Instead of having a deep sea sophisticated complex firmware data filter system, which is also very power consuming, all data is sent to shore. Therefore the absolute minimum of electronics below sea level is desired. The filtering and the reconstruction of event data is done at the Shore Station using a PC farm. This is known in Antares as the All Data-To- Shore design. Single photons produce in 98% of the count rate 48 bit data words. For the remaining 2% and more complex- events, 2104 bit data words are generated. Physics simulations predict an overall datarate from each and M of ~ 20Mb/s to 60Mb/s. max. The digitized source data from the 3 PMs in the is sent to the M using 100BASE-TX Ethernet. In the M the 5 datasteams from 4 s and from the M itself is combined via an Ethernet Switch and sent to the Shore Station. This total Sector data is transported by using Gigabit Ethernet, the overall dataprotocol for the DWDM DAQ in the Antares detector. Each of the 6 Sectors occupy one channel in the DWDM system. The Detector Slow Control data, located in the SCM, is transported by Ethernet 100BASE and occupies the 7 th channel in the DWDM. The data network connectivity from the to the PC farm is TCP/IP. Basic Optical Network Design The basic 200GHz spaced DWDM design is presented in figures. 1 and 2. (page 10 and 12) From 5 's, data is sent to the M container (one module is part of the M container). Via the Gigabit Ethernet, the data flow from each is subsequently sent to the M-DWDM board which contains the Electro-Optical converters. The data on a unique optical wavelength λ x for each channel per M is sent to the SCM container via one of the 21 fibers in the EMC (electrical mechanical cable) on the appropriate channel input of the DWDM-multiplexer. An 8 channel, 200 GHz spaced DWDM-multiplexer is used because of the filter specifications (fig 4)..This filter type has less crosstalk between adjacent channels and wider filters with regard to 100 GHz spaced DWDM filters. From here the data from all the M's on wavelengths λ x(0:6) is sent to the Shore Station via the SPM (String Power Module), IC (Interconnect Cable) and Junction Box and 50 km seacable and 5 km of standard fibers to the DWDM-demultiplexer (fig 2) Physically the EMC cable is installed into and out off each container in serie, Every conductor and fiber is cut and reconnected for the next container.

5 DWDM Electronics 5/14 At the Shore Station an optical splitter is inserted for online signal monitoring for optimizing the optical network performance. The demultiplexed optical signals are converted to an electrical bitstream and then to 1000BASE-SX Gbit Ethernet. These SX lines connect to the Gigabit Ethernet Switch which directs the data for filtering and analyses to the PC farm. The 7 th channel λ x6 is singled out as 100BASE-TX Ethernet for Slow Control in the detector string. Vice versa: From the Shore Station to the detector, the Gigabit Ethernet is data modulated on the optical wavelengths λ y(0:6) and sent to the SCM Container. The DWDM-demultiplexer separates the dataflow λ y(0:6) to independent wavelengths λ y. From here the wavelength λ y is sent in the matching M container. Provisional classification of DWDM-channel distribution for the DAQ part and the detector SC(slow-Control) for the SCM container is shown in table 1. Optical Network Monitoring. In each fiber at the shore station an optical broadband splitter (fig5 )is implemented for the optical network monitoring. At this point optical instrumentation can be employed for on-line monitoring and operates with optical network control. DWDM Channel Distribution In the table the wavelength label of the ITU T G.692 nominal center frequencies throughput with the matching DWDM (de)multiplexer and fibers is shown.and fits in the fibers windows of opertunity. (the choosen channels was formally done when bandpass filters were still in the design) The expired bididrectional use of fibers makes the choise of the UTI channels equal to both directions. Table 1: DWDM channel distribution Label ITU freq fiber SMF 28 DWDM (de)mux fiber Alcatel PSC λ x0 21 in in in λ x1 25 in in in λ x2 29 in in in λ x3 33 in in in λ x4 37 in in in λ x5 41 in in in λ x6 45* in in in λ x7 49* in in in (edge) λ y0 21 in in in λ y1 25 in in in λ y2 29 in in in λ y3 33 in in in λ y4 37 in in in λ y5 41 in in in λ y6 45* in in in λ y7 49* in in in data from detector to the shore station data from shore station to the detector for "*" see next page

6 DWDM Electronics 6/14 * λ x6 51 channels for 100Mb Ethernet λ y6 33 for Slow Control (detector control) λ x7 53 spare λ y7 35 spare NOTE: A different channel classification depends upon an optimum between Alcatel's PSF fiber window of opportunity, a wider range of availability and costs about DWDM multiplexers and DWDM-lasers. The optical fibers in the 50 km. sea cable from the Junction Box to the Shore Station mainly determine the wavelengths in the ITU nominal center frequencies grid in the window of opportunity. The main limiting specifications of this Alcatel PSF cable (ITU-T G654) in table 2, are the operating wavelength window of 1535nm nm. All Antares DWDM wavelengths used must fit in this window. Table 2: Alcatel Seacable Specification: PSF ITU-T.G654. (ITU-T.G654 denotes a Cut-off Shifted Fiber) (data from Fax Alcatel dated: ) Parameter Value Notes Operating Wavelength 1535nm 1570nm Attenuation db/km estimation /not specified Cut-off-wavelength nm?? Localized attenuation variation <0.05dB Reflection Peaks Not allowed Chromatic dispersion <21ps/nm.km Mode field diameter µm Fiber diameter 125µm ±3µm Concentricity error < 1µm Non circularity of cladding <2% Coating diameter 250µm ±15µm Every DWDM channel in table 1 specifies a unique ITU wavelength for the electro-optical parts. For service and easy replacement at the testing stage and final launching of the entire string, the channels 35 and 53 are designated spare channels. Spare cards can be prepared in advance. See also Part II.

7 DWDM Electronics 7/14 Calculated Optical Loss Table In table 3, the expected optical insertion loss in each component from the top M to the optical receiver for is displayed. Table 3: Detector to Shore Station data direction: 1. M-DWDM(top) to DWDM-mux 30 connetions (a splice typ: db -a connector typ: 0.2 db) ~ -4.0 db m SMF28 string cable(emc) -0.1 db 3. DWDM-Mux -3.6 db max 4. Splice DWDM to fiber (EMC(2)) db* 5. Splice In SPM -0.1 db* m cable from SCM to SCM container connector (IC) on JB -0.1 db 7. PCM container fiber JB connector -0.5 db* 8. JB connector to the Alcatel PSC cable -0.2 db 9. JB connector to 50 km sea cable conn db* km Alcatel PSC cable db 11. Splice Alcatel 50 km to 5 km SMF28 fiber -0.1 db km SMF db 13. Splice 5 km SMF28 cable to Broadband -0.2 db* monitor splitter 1% 14. splice Broadband monitor splitter 1% to -0.2 db* DWDM 15 DWDM Demux -3.6 db max 16 Splice DWDM-Demux to Pin-Detector -0.2 db +======= Total optical loss of passive network db * Standard loss for splices and connectors (Diamond or Opto clip). No specifications for submarine connectors are available at this time. Optical System Power Budget/Margin In this type of network a laser output power of 8dBm is used. More insertion power causes a not negligible back scattering factor in fibers and/or connections must be engineered. Most Pin-Diode based Receivers have a typical sensitivity of typ. -24dB.(-20dB min) An allover optical system margin of 6dB is mandatory to compensate for aging effects and possible inferior splices and connectors. Optical Budget: DWDM-Laser at 8dB + Pin-Diode based amplifier at -24dB = 32dB The optical margin is ~ 6dB This leaves a maximum attenuation in the passive optical network of 26dB.

8 DWDM Electronics 8/14 Important Notice: The optical network is carefully calculated in terms of optical losses, wavelengths and components. It is coherent with the system optical margin. Not approved components, value change or components added, like extra splices etc. anywhere in this optical network will disturb correct operation of the entire DWDM optical network. Polarization Dependent Loss. The DWDM and the broadband coupler have a polarization loss of 0.1 db each. Total PDL system loss is -0.3 db. Polarization Mode Dispersion. The data rate of 1.25 GHz (Gigabit Ethernet NRZ) and the length of the 50 km seacable are estimated to have neglectable polarization mode dispersion effects. Active Opto-Electrical conversion The Opto-Electrical conversion parts are described in part II of this document: ETR Passive Optical Parts Optical cables/fibers: Corning SMF 28 from Sector to SCM (2 fibers, uni-directional) Corning SMF 28 from SCM to SPM (2 fibers, uni-directional) Corning SMF 28 from SPM to JB (2 fibers, uni-directional) Alcatel PSC ITU-T G654 from JB to Shore Station (2 fibers, uni-directional) (table 2) Possible Optical parts from E-Tek Dynamics (product catalog 1999) DWDM 2F M8 C21 3 x for both the Multiplexers (fig 4) DWDM 2F H8 Cxx.. 3 x for both the De-Multiplexers (fig 4) SWBC A S 2 4 x for the monitor functions.(fig 5) Note: passive optical components like the above and the fibers are considered to have over their lifetime temperature neglectable drift and aging. Optical Circuit tolerances The laser center frequency shift is similar on the laser described in part II of this technical document. On worse case center frequency drift the laser power will be lost in the DWDM filter. No tolerance is given in the E-Tek technical parameters.

9 DWDM Electronics 9/ nm λ nm +3.2 nm laser initial tolerance: λ 0 +/- 0.1 nm max. chirp : λ 0 +/- 0.1 nm aging: λ 0 +/- 0.1 nm total tolerance: λ 0 +/- 0.3 nm pass channel effective bandwidth pass channel effective bandwidth max and min shifts by temperature nm/ o C pass channel effective bandwidth exclusive initial filter central frequency tolerances Circuit Simulations An optical circuit simulation on this design has been performed. A report is available NIKHEF/../JH A lack of minor specifications and differences in specification standardization on the foreseen fiber and opto-components, makes practical measurements indispensable. References 1. Conceptional Design Report Nov DWDM design proposal by Erwin Kok (NIKHEF) as from mid 1999 Gbit Ethernet tranmission details are figured out by E. Kok and HZ Peek (NIKHEF) 3. Principels of Optical Fiber Communication by W. van der Etten isbn Products Breakdown Structure for Embedded Electronics 3 02 xx/a 5. E-Tek Dynamics product catalog Private contacts with the Opto laboraty of the University of Eindhoven 7. Private contacts with employees of Lucent, Alcatel, JDS Uniphase, Simac 8. Private communications with the NIKHEF Antares team 9. Private communication with M. van der Hoek from Coenecoop engeneering

10 DWDM-mux DWDM Electronics 10/14 junction box JB EOC conn. to/from shore station submarineconnector ( ) 10 x on JB one for each string basic DWDM outline sea side NIKHEF Antares Project nr Januari 4, 2001/jh/rev2 IC M container SCM container M-DWDM M-DWDM SCM-DWDM λ x0 ch xo n+29 λ y0 λ x1 ch yo n+24 ch x1 ch y1 n+1 λ y1 EMC λ x2 M-DWDM λ y2 n+19 ch x2 ch y2 SPM DWDM-demux M-DWDM λ x3 n+14 ch x3 λ y3 ch y3 M-DWDM λ x4 λ y4 λ y6 λ x6 n+9 ch x4 ch y4 M-DWDM λ x5 ch x5 λ y5 n+4 ch y5 n+1 n MHz Ethernet for detector control EMC EMC physical installation trunk with cumulative number off splices on all fibres fig 1 n+3 n+2

11 DWDM-mux DWDM Electronics 11/14 basic DWDM outline shore side NIKHEF Antares Project nr Januari 4, 2001/jh/rev2 Data process ch xo ch yo ch x1 ch y1 ch x2 ch y2 ch x3 ch y3 ch x4 ch y4 ch x5 ch y5 λ x0 λ y0 λ x1 λ y1 λ x2 λ y2 λ x3 λ y3 λ x4 λ y4 λ x5 λ y5 λ y6 λ x6 monitor SWBC monitor SWBC 5 km SMF MHz Ethernet for detector control 50km seacable from/to detector fig 2

12 DWDM Electronics 12/14 fig 4

13 DWDM Electronics 13/14 fig 5

14 DWDM Electronics 14/14 End of document