1. EVLA Fiber Selection Critical Design Review December 5, 2001

2. Fiber Selection CDR Decision about what fiber to install — Select cable (Jan 02) — Order cable (Jan 02) — Receive cable (May 02) — Start installation (June 02) — Complete install (June 03)

3. IF Scientific Requirements Samplers Dominate the Digital Performance — Input Bandwidth2-4 GHz — Clock Rate 4096 MHz — Resolution3 Bits — Aperture Time50 Ps — Clock Jitter5 Ps — Clock Rise Time25 Ps

4. IF - DTS Specifications Bit-Error-Rate (End-of-Life)10 -6 Data Bit rate per Polarization24 GHz Data Bit rate per Antenna (12)96 GHz Formatted Bit rate per Antenna120 GHz Jitter ContributionN/A Loss of Synchronization<1% Loss of Data

6. Task at Hand Select a fiber and a Configuration that can transmit the IF data from the antennas to the correlator. — Identify Optical Requirements — Compare Fibers — Select Fiber

7. Identify Optical Requirements

8. IF Parameters -12 C to 35 COperation Temperature 625 mMinimum Fiber Length 21.6 kmMaximum Fiber Length 6 - Initial, 4.7 - FinalDigital RMS SNR (Q) 10 -9 Initial, 10 -6 FinalBit Error Rate C-BandChannel Wavelengths 200 GHz SpacingChannel Spacing 12 or 16 ChannelsNumber WDM Channels 10 Gbits/sBit Rate / Channel

10. IF Signal Path

11. Types of Fiber Analyzed Corning Products — SMF-28, Standard Single Mode Optical Fiber — MetroCor, Non-Zero Dispersion Shifted Fiber — LEAF, Large Effective Area Fiber All three fiber types will work for EVLA

12. Fiber Allocations IF 120 Gbps WDM1 LO - 2.048GHz, 512 MHz, 128 MHz1 MCB Ethernet2 Emergency Communication1 Telephone Digital System2 Total Lit Fibers per Antenna7 12 Fibers Installed per Pad with 5 spares

14. Fiber Comparison

15. Transmission Losses

17. Erbium Doped Fiber Amplifiers — ( )

18. OEM of EDFA

19. EDFA Performance All channels will fall in the linear region

20. Result #1 Single Mode Fiber with an EDFA will have adequate optical power. But what about Q ?

21. Digital SNR (Q) Q is the ratio of signal current to noise current. Q = ( I 1 - I 0 ) / ( i 1 + i 0 ) ( I 1 – I 0 ) is the excess electric signal available for distinguishing between a 1 and a 0. ( i 1 + i 0 ) is the RMS electric current induced by noise during a transition.

22. Transmission Quality For BER = 10 -9 the system requires: Received Q > 6 Received power > –20 dBm.

23. Eye Pattern

24. Polarization Dependent Loss

25. Chromatic and Polarization Dispersion

26. Power Penalty Budget

27. Q Budget

28. Result #2 Achieve a BER of 10 -9 — Launch Requirements - 10 Gbits/s @ 0 dBm — Launch Q = 31 Receiver — Assumes sensitivity -20 dBm — 10 -9, @ 10 Gbits/s

29. Cost Comparison

30. Fiber Allocations

31. System Budget

32. CDR Recommendation Single Mode Fiber, SMF Twelve fibers per pad Fourteen connectors Twenty-seven erbium doped fiber amplifiers Prototype before purchase