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Packaging opto components: how much can we do ourselves?

Packaging opto components: how much can we do ourselves?. Historical summary from ATLAS & CMS trackers New developments for ATLAS tracker off-detector optoelectronics Discussion. On-detector Optoelectronics. Constraints are: Radiation tolerance No magnetic material Small Low power

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Packaging opto components: how much can we do ourselves?

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  1. Packaging opto components: how much can we do ourselves? • Historical summary from ATLAS & CMS trackers • New developments for ATLAS tracker off-detector optoelectronics • Discussion Opto WG TWEPP 2012

  2. On-detector Optoelectronics • Constraints are: • Radiation tolerance • No magnetic material • Small • Low power • Low radiation length contribution  low Z materials. • Last but not least: Extremely good reliability • Not obvious that all these requirements will be met by commercial components, e.g. non-magnetic. Opto WG TWEPP 2012

  3. ATLAS SCT • SCT: custom package designed by AS Taiwan. • Old and slow (obsolete) p implant VCSEL • Wire bonding to the VCSEL • 45 degree angle polished fibre above VCSEL, eliminates need for epoxy on VCSEL surface. • Same technique for Si p-i-n diode (slow). Opto WG TWEPP 2012

  4. CMS Tracker • CMS Analogue Opto Hybrid (AOH) • 3 channels laser drivers, lasers and fibres • Minor tweak of commercial OSA ATLAS Tracker Upgrade Liverpool December '06

  5. CMS Laser Sub-Mount • Compact: 4.5 * 4 * 1.3 mm3 • Fibre ends gold plated • Active alignment: resistor pads used to solder fibre in location. Glue only for strain relief of fibre • Radiation hard by design Removed for CMS (save $)

  6. Off-detector optoelectronics • No constraints on radiation hardness, non-magnetic material, radiation length. • Space constraints in crates favour arrays over single channel devices. Opto WG TWEPP 2012

  7. ATLAS SCT/Pixel arrays • Same package for SCT & Pixel off-detector BOC. • Same package also used for ATLAS pixel on-detector. Opto WG TWEPP 2012

  8. Used for Pixel on-detector and SCT/Pixel off-detector BOC 12 way array with MT guide pins for coupling to 12 way ribbon fibre Epoxy over surface of VCSEL  CTE mismatch  problem with thermal cycling? ATLAS Tracker Upgrade Liverpool December '06

  9. CMS AnalogReceiever • 12 channel receiver: minimal mods to commercial components: • Same 12 channel PD array • Replace the receiver ASIC PD array and ASIC MPO adaptor Ceramic package (can be hermetically sealed). Opto WG TWEPP 2012

  10. CMS Transceiver • 4 channel transceiver for control links • COTs Opto WG TWEPP 2012

  11. Reliability History (1) • CMS: excellent, no reported laser/pin diode deaths during operation. • ATLAS on-detector • ~ 1.3% non-functional data links, mostly but not all due to VCSEL failures. • “delayed infant mortalities”. VCSEL channels died during commissioning and early operation • death rate appears to have decreased, 5 deaths during 2011 run (5 fb-1) and 2 deaths so far in 2012 run (15 fb-1) Operational time scales with integrated luminosity because of NRZ data. • Long term “harness test”. 41 channels operated for 271 days (longer on-time than 10 year LHC) showed no failures  don’t expect catastrophic end of life failures. No change in OSA. Opto WG TWEPP 2012

  12. Reliability History (2) • ATLAS off-detector arrays. • Very short lifetime observed. ESD problems identified and fixed. • Small improvement in lifetime observed. VCSEL sensitivity to humidity identified. This could explain why no confirmed VCSEL deaths seen in pixel on-detector which uses same VCSELs and packaging. • However long term tests in SR1 not consistent with death rate in ATLAS, so humidity is not the only factor. • TL VCSEL replaced with AOC which is known to be humidity resistant. SCT has 13 channel failures, • 5 “infant mortality”, 8 “random”, in ~ 1 year operation. Opto WG TWEPP 2012

  13. New Developments for ATLAS • Trying to develop a reliable backup solution for ATLAS that is backward compatible, ie new TX PCB that satisfy: • Fit in space on BOC • Same electrical connector • Optical MT connector, compatible with Infineon SMC. Opto WG TWEPP 2012

  14. iFlame • Concept was to make minor tweak of commercial component (4 channel TRx) • Design for integration in ATLAS very successful and demonstrated with 4 TRx next slide. • Many problems • Difficulty producing devices with new wafer fab. • No useful reliability data • Devices never used in any applications • First 12x devices only recently available and not yet meeting ATLAS specs Opto WG TWEPP 2012

  15. heat sink BPM-12 in BGA VCSEL in iFlame package MT guide pins

  16. iFlame 12X • Finally light from the iFlame 12x integrated into an ATLAS TX • Reasonable quality optical signal • Some x-talk visible but probably acceptable • Optical power still low but should be improved with better alignment of the lens/mirror array. • Will it be reliable? Opto WG TWEPP 2012

  17. LightABLE engine • LightABLE engine is a commercial (Reflex Photonics) part. • Small enough to fit. • We want to reuse new TX PCBs designed for iFlames BPM-12 o/p  LVDS driver  Optical engine. • Proof of principle tested and space model showed it can fit. Opto WG TWEPP 2012

  18. LightABLE ATLAS TX • Integration into ATLAS BOC possible because: • Small form factor  compatible with space constraints in ATLAS BOC • MT-12 connector • Contains laser driver ASIC • BPM-12  LVDS driver  LightABLE engine Opto WG TWEPP 2012

  19. LightABLE TX BPM-12 LightABLE engine Opto WG TWEPP 2012

  20. Discussion • Many reliability problems with custom packaging. • Even if we could produce a reliable package we couldn’t afford sufficient testing to prove it (need ~ 1000 devices * >1000 hours operation). • On-detector  minimal changes to commercial components. • Off-detector  Stick to purely commercial components. • Calorimeter optoelectronics: listen to Annie’s talk before discussion … Opto WG TWEPP 2012

  21. Backup Slides Opto WG TWEPP 2012

  22. LightABLE Dimensions Opto WG TWEPP 2012

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