1. Opto-Rx Measurements for Pixel Upgrade M.Friedl, M.Pernicka HEPHY Vienna

2. Opto-Rx Measurements for Pixel Upgrade 2M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 What? Why? How? Digital optical 320 Mb/s transmission is intended for pixel phase 1 upgrade Recycling of existing optical links possible? –Sender side appears OK –Most severe bandwidth limitation in 12-way receiver (ARx12) ~100 MHz Comparative test of digital transmission at 320 Mb/s between existing ARx12 and Zarlink engineering sample Each mounted on test board (clean environment) ARx12 with external fast, self-biased, LVDS-output comparators (ADCMP604) ARx12 Zarlink Comp.

3. Opto-Rx Measurements for Pixel Upgrade 3M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 Sender / Receiver Setup Agilent 8110A pulse/pattern generator AOH (TOB type) AOH test setup Tektronix DSA70804 Scope Receiver boards

4. Opto-Rx Measurements for Pixel Upgrade 4M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 Test A – Unbalanced Periodal Signals 40 MHz with variable duty cycle (T on /T period ) Considerable distortions up to misinterpretation due to threshold imbalance Bad result. However: This is a very unrealistic situation… Example: 25% duty cycle represents repetitive unbalanced 1100 0000 code T on T period CodeSender Opt_Head (analog)ARx12Zarlink 1111 000050.0%49.8%47.3%50.1% 1100 000025.0%25.6%32.7%35.3% 1000 000012.5%12.4%27.0%--- Receiver

5. Opto-Rx Measurements for Pixel Upgrade 5M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 Test B – Balanced PRBS @ 320Mb/s with Sequence of 0s or 1s 15000 words of programmable pattern filled with PRBS14 (=balanced) Programming 1s (or 0s) from the beginning of the pattern until remaining PRBS bits become corrupted Amazing result: –Zarlink tolerates ~700 consecutive 1s (or 0s) without effect on subsequent pattern –With more than ~700 same symbols, subsequent single bits deteriorate or vanish completely (symmetric behavior) –ARx12 even tolerates ~3000 consecutive 1s Perfectly suitable for pixel system, where even 20 consecutive 1s or 0s are extremely unlikely

6. Opto-Rx Measurements for Pixel Upgrade 6M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 Test C – Eye Diagram @ 320Mb/s (1) Optical Head (analog) Limited rise time (mostly due to pattern generator) Stable timing Solid eye opening

7. Opto-Rx Measurements for Pixel Upgrade 7M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 Test C – Eye Diagram @ 320Mb/s (2) Zarlink (digital) Perfectly fine High bandwidth (Zarlink can do 1.6Gb/s)

8. Opto-Rx Measurements for Pixel Upgrade 8M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 Test C – Eye Diagram @ 320Mb/s (3) ARx12+comparator (digital) Narrow opening with best settings of pulse generator (amplitude), AOH (offset) and Rx12 (offset) Unusable with non- optimal settings (where Zarlink still works perfectly well)

9. Opto-Rx Measurements for Pixel Upgrade 9M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 Test Conclusions ARx12 performance is marginal – even on a lab test bench in a noise-free environment Needs careful tuning of parameters in order to work Hence we don’t recommend its use in a production system Zarlink works very well – but is not a commercial product Normally 850nm, this engineering sample has 1310nm photodiode Francois is in contact with manufacturer to see if we can get 200 pcs. of 1310nm wavelength version Alternative: ARx12 mechanics + photodiode with faster (digital) amplifier Roland is in contact with manufacturer (Helix)

10. Opto-Rx Measurements for Pixel Upgrade 10M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 Modification of Pixel-FED (1) New daughter board (instead of 3 ADC cards) including Zarlink receiver Don’t need to remove current ARx12  allows easy swapping between old and new systems Need new front panel in any case Keep single slot size Keep VME base board

11. Opto-Rx Measurements for Pixel Upgrade 11M.Friedl, M.Pernicka (HEPHY Vienna)23 April 2009 Modification of Pixel-FED (2) Old ADC card New daughter board Zarlink (mounted on daughter board) Front panel VME board Need higher connectors than now Available from different vendor (samples ordered for compatibility tests) OLD NEW ARx12