KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 1 of 36 Read-out and transmission technologies for optical modules  an asynchronous read out system  a synchronous read out system ( and what about PMT pulse shape signal transport by e.g. use of delta modulation?)

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 2 of 36 vdsl2 10kV/380V Ref: Catania 380V Master Module LINE 1 apd 1 ADM logic switch vdsl2 380V/3.3V logic x PMT OM 1 <100Mbps vertical Cable e.g. VDSL2 Main cable GPS rec. Shore station laser 1..n 1 n Clock apd clck-sc-cal. Logics CPU Farm 10KV DC Power System apd branch equivalent 10kV JB1 branch Anchors LINE 2..n and JB2 vdsl2 OM V data  n seed. c c 2.. n An asynchronous read out system

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 3 of 36 Read out and data transmission for KM3NeT CONCEPT I An asynchronous read out system (store and forward)  Time stamped event data is stored locally in buffers or memories in the optical modules The data is transported to the shore under control, e.g. Ethernet.  The clock system can be implemented supplementary in the data acquisition system else a complementary clock system is needed. Detector control and calibration can be implemented as part of the data acquisition system.  The physical layer implementation at detector level can be copper or a copper-optical fiber mix cable. Choices depend on the data rate, transmission speed and the range of distance.

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 4 of 36 A synchronous read out system GPS rec x Shore station PMT Optical module laser 1..n 2 n+1 1> n+ n+1 data ~20 x Clock apd clck-sc-cal. data GbE Copper Logics CPUs ~32 x Power apd Clock cal ½ns electronics c c REAM Power  n seed. 1 line Breakout to OM apd

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 5 of 36 Read out and data transmission for KM3NeT CONCEPT II A synchronous read out system (real time transmission)  Carried out in optical point to point connections, 1 fiber can carry ~100 optical channels  Event data is synchronously send to shore. The on shore readout system transports data to shore on a “heart beat” with a fixed sequence. This real time data throughput consequently has no data congestion.  The clock system is an intrinsic part of the data transport system. The signal propagation from optical module to shore is calibrated. On shore the event data time stamp is corrected with this propagation time. Time accuracy is ~100 psec. The CDR timing requirements are 1 nsec.  The detector control or associated systems are free to implement their particular data transport solutions.  The optical channels are transparent, have a bandwidth from a few Hz to 10 Gbs.

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 6 of 36 Test for bidirectional data transport over one optical channel

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 7 of 36 The bidirectional transmission test setup at the University of Eindhoven Conclusion: works well at maximum span of 2000 m

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 8 of 36 Pro’s and Con’s Comparing figures for: Reliability Deployment aspects Costs Manufacturing time Life time (MTBF) Detector power needs Calendar time for construction ---- etc. But we need cable !!

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 9 of 36 Status of electrical- and optical transmission measurements on a proto type vertical cable for deep sea use Unshielded Twisted Pair Transmission characteristics of UTP (cat5) in a silicon oil environment Electrical network analyzing Optical fiber: Corning SMF-28 ( standard single mode fiber with Draka Comteq pressure resistant coating) Optical 1310 nm OTDR -- optical time domain reflection -- reflections and optical loss CD -- Chromatic dispersion – on short cable minor influences compared to PMD PMD -- Polarization mode dispersion -- Mechanical behavior (pressure, torsion, bending etc.) using a Stimulated Brillouin OTDR Object: Exploring electrical and optical behavior of the cable and connectors from atmospheric pressure to deep sea pressure up to 600 Bar (6000 m.)

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 10 of 36 Survey of the test cable and connectors 25 m. 1.0 m Connector: 4 twisted pair cables 40 optical fibers Connector: 1 twisted pair cable 34 optical fibers Connectors 1 twisted pair cable 2 optical fibers

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 11 of 36 Survey of the test cable and connectors 2

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 12 of 36 Survey of the test cable and connectors 3

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 13 of 36 Survey of the test cable and connectors 4

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 14 of 36 Electrical network analyzes It is for measuring transmission parameters ( among the S21 parameter forward transmission coefficient (gain)) of the Unshielded Twisted Pair in the proto type deep sea cable. UTP properties: Wire type: 20 AWG Housed in Silicone-Oil (  r = 2,7) => Z 0 ~ 76 ohm A network analyzer is an instrument used to analyze the properties of electrical networks, especially those properties associated with the reflection and transmission of electrical signals known as scattering parameters (S-parameters). Network analyzers are used mostly at high frequencies; operating frequencies can range from 9 kHz to 110 GHz.

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 15 of 36 Note: Tap-Termination Adds -3 dB 30 MHz 50 MHz Termination Connector Stub Tap terminated (82  ) Significant attenuation (34 dB) at 30 MHz (e.g. upper VDSL2 frequency). Probable cause: loss due to the high dielectric figure of the applied Silicone-Oil Network analyzes 100m cable with terminations Gain 10dB/div. frequency 0 dB

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 16 of 36 Network analyzes reference cable 100 Mtr “EHE A 2 PR” => Attenuation 21,4 dB at 30 MHz Shield keeps electric field inside the cable which contains a low loss Dielectric. The Silicone-Oil which has a high loss dielectric parameter 30 MHz Gain frequency

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 17 of 36 Network analyzes conclusions The current twisted pair in the proto type cable: – Has Group Delay that is fine – But has High Dielectric Loss – And the stubs must be terminated (extra electrical loss) Future improvements – If possible use a different low loss silicone oil (e.g. transformer oil D = 0,0001) – Avoid stubs

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 18 of 36 contaminated end face “Standard” view contamination also due to static charges in the cross section A just cleaned end face 125 µm core 9 µm Why cleaning optical connectors? Magnified 400 X Intermezzo

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 19 of 36 Cable test setup at Nikhef Network analyzer Cable under test Fiber microscope PMD analyzer PMD analyzer has been set to our disposal by EXFO OTDR Dark chamber for the multi PMD test setup

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 20 of m. source Rec dBm-7.50 dBm Loop connection Deep sea connector Loop length ~3750 m (36 in the cable assembly and 2 m pigtail/fiber) Attenuation for total loop : nm (~ nm) 144 connections average of ~ 0.2 dB loss per 1550 nm Optical loss per connection in calculations between 0.5 dB to 1.0 dB Open for OTDR Measurement +100m fiber Optical Loop test setup

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 21 of km end of segment reflections on connectors 5 dB/div. 500 m/div. ~10 dB loss Loop test OTDR value over 1000 m.

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 22 of 36 PMD effects, general introduction Cross-section asymmetry Stress Torsion Temperature changes Polarization Mode Dispersion is observed by a time delay between two orthogonal polarization modes at the output of the fiber. The PMD coefficient is expressed in ps/  km A generally excepted rule: The absolute PMD value may not exceed 10% of a bit period over the entire fiber span (e.g. 10Gb/s -> max PMD of 10ps) input output

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 23 of 36 Measuring PMD Measurements according to ITU specifications FOTP-24 (standard method fiber optic test procedure) EXFO PMD equipment measures according to FOTP-24a Corning optical cable SMF128 Time psec. Intense in % < 0.04 ps/  km

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 24 of 36 PMD effects in the test cable 40 femto sec.

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 25 of 36 Test in the pressure vessel at NIOZ Pressure vessel spec’s: up to 600bar, Ø 0.80 meter, length 1.80 meter at NIOZ (Royal Institute for Sea Research) Texel The Netherlands

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 26 of 36 Light source -6dBm attenuation ~44 dB Attenuation over 120 connections < 0.3 dB/connection Cable Assembly in pressure vessel

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 27 of MHz Significant attenuation over 100m 34 dB at 30 MHz gain frequency Transmission transient result in pressure vessel 100 m UTP at atmospheric pressure and no change up to 200 bar

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 28 of 36 OTDR result in pressure vessel all fibers ~ 3674 m atmospheric pressure recovers from a saturated reflection signal Optical loss over 3 connections Amplifier noise from OTDR Optical loss over 3 connections Fiber length Attenuation (dB) Reflection in end faces of 3 connectors

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 29 of 36 ~ 5 dB loss on connectors (of fiber 16 to 17) No significant loss on the fiber at 200 bar OTDR result in pressure vessel all fibers ~ 3674 m pressure 200 bar

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 30 of 36 PMD result in pressure vessel all fibers ~ 3674 m atmospheric pressure PMD: ps Coefficient: ps/km^1/2 Result perfect

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 31 of 36 PMD: ps Coefficient: ps/km^1/2 Result: within specifications for 10Gb/s (10 psec) PMD mesurement result in pressure vessel all fibers ~ 3674 m pressure 200 bar

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 32 of 36 Oil leakage responsible for the failed tests Popped electrical assembly

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 33 of 36 Catastrophic design error

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 34 of 36 Solution proposed within a week time from failure Seacon connector

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 35 of 36  Timing measurements, propagation time accuracy over fiber (including EDFA’s)  BER tests (over 100km) from 100 Mb/s to 10 Gb/s with CW laser seed to REAM  Renewed cable assembly tests under pressure including a DWDM multiplexer. Among: PMD behavior Stimulated Brillouin OTDR measurements (stress in the fiber) Transmission tests in the near future

KM3NeT WP3 meeting Genova Jelle Hogenbirk et al. electronic department 36 of 36 KM3NeT teams of Nikhef Mechanical Workshop Mechanical Engineering department Electronic Technology department CIP Ltd. Ipswich (UK) Seacon Europe NIOZ: Royal Institute for Sea Research Van der Hoek Photonics Technical University of Eindhoven (NL) Rood Engineering for the EXFO optical instruments On behalf of