0. Versatile Link F. Vasey, CERN On Behalf of the Versatile Link Project Mini Opto Workshop, 5th March 2010
5 Mar 2010

1. Versatile Link Project Description
Optical Physical layer linking front- to back-end
Bidirectional, ~5Gbps
Versatile
Multimode (850nm) and Singlemode (1310nm) versions
Point to Point and Point to Multipoint architectures
Matching SLHC tracker environment, plus others
Joint Project (CERN, Fermilab, Oxford, SMU) FE BE
5 Mar 2010

2. Template TRx: SFP+ Transceiver
Bi-directional Module with connector interface
Based upon an acknowledged standard
Work with Industrial partner early-on
MM 850nm & SM 1310nm versions
Bitrate 2.5 – 10 Gbps
Fast access to hardware
Easy distribution to integrators
Customization in second step
5 Mar 2010

3. Evolution: Front End Transceiver, VTRx
TOSA
ROSA
GBLD
GBTIA
Low Mass & Volume
Minimize material, avoid metals
Non-magnetic, capable of operating in a magnetic field
Requires replacement of ferrite bead used in laser bias network
Bitrate determined by ASICs: 5 – 10 Gbps
850nm and 1310nm flavours
2Tx
TOSA
ROSA
GBLD
TOSA
TOSA
5 Mar 2010

4. Evolution: Backend Transceiver
SFP+ TRx
SNAP12 4TRx
or 12Rx
Fermilab has made a substantial investment in test equipment during This investment includes the purchase of a Tektronix DSA8200 Digital Signal Analyzer. This is shown at the top center of the slide.
This mainframe hosts an O/E converter head which is used to gather optical transmitter performance data Tests that were performed earlier on our older Tektronix 11801B sampling scope required LabView software to implement the tests. The newer DSA8200 has these measurements and more automated at the push of a button. The figure of an optical eye pattern shows the results of these tests being updated through the data collection interval (right hand side of the figure).
The pattern sync module allows a trigger to be delivered to the sampling head at the repetition rate of a pseudorandom bit stream (PRBS) input. This was not possible with the older 11801B scope. Because of this capability, jitter analysis software was also purchased and is being used to characterize the various jitter sources (deterministic and random) that are present in the test setup. The software compiles probability density functions for these jitter sources including the data dependent jitter as a function of the bit positiono in the PRBS. In addition, statistical predictions of the eye pattern required to achieve a specified level of bit error rate are available.
Test Equipment Procured and Test Lab Configured
Evaluation of SFP+ 10 Gbps 850 and 1310 nm (ongoing)
Evaluation of array and 1310nm (ongoing)
Partnership with Vendor for dense light engine Prototyping (ongoing)
5 Mar 2010

5. The Versatile Link Project Roadmap
Project proposal submitted to ATLAS and CMS SLHC upgrade steering groups in Nov07
Project endorsed by ATLAS and CMS in early 2008
Kick-off Meeting 10 Apr 2008
3 phases of 18 months each
phase 1 proof of concept based on tentative specifications, partial tests and early prototypes
Apr08 – Sep 09
Phase 1 closeout meeting 20th Sept
Phase 2: feasibility demonstration based on complete specifications and exhaustive tests on final prototypes
Oct 09 – Apr11
Specs and procedures
Tests and Results
List of COTS components and suppliers
Test-systems and Prototype custom components
Phase 3: specifications freeze, pre-production readiness, technico-commercial actions
Apr11 – Oct12
5 Mar 2010

6. Next Steps (2010-2011) FE BE ROSA TOSA Optical Subassemblies (ROSA)
Packages (VTRx, Light Engine)
Specifications
Testing (characterization, irradiation (SEU, TID, TF), comparison)
Prototypes distribution for evaluation
TOSA
ROSA
GBLD
GBTIA FE BE
5 Mar 2010

7. Components and Subassemblies
ROSA
TOSA
Phase 1 ( )
Proof of concept
Phase 2 ( )
Feasibility
GBTIA
ROSA
TOSA
ROSA
GBLD
GBTIA
5 Mar 2010

8. Credits and References
CERN
Jan Troska, Luis Amaral, Stefanos Dris, Alberto Jimenez Pacheco, Sarah Seif el Nasr, Christophe Sigaud, Sergio Silva, Csaba Soos, Pavel Stejskal, François Vasey
Fermilab
Alan Prosser, Mark Bowden, John Chramowicz
Oxford, IPAS, CERN
Todd Huffman, K. Dunn, Alex Gerardin, Cigdem Issever, S.C. Lee, Z. Liang, Z. Meng, A. Povey, Tony Weidberg
Southern Methodist University
Jingbo Ye, Andie Liu, Kent Liu, Annie Xiang
The radiation tolerance of specific optical fibres exposed to 650 kGy(Si) of ionizing radiation, 2009 JINST 4 P0710, published
The Versatile Link, A Common Project For Super-LHC, JINST_002P_0709, to be published
5 Mar 2010