# Presentation: 198799

## Optical Hybrids

- K.K. Gan
- The Ohio State University

- WBS 1.1.1.4

- US ATLAS Review

- K.K. Gan

## Outline

- Introduction
- Opto-package prototypes
- Opto-hybrid board design
- Cost and schedule summary
- Conclusions

- US ATLAS Review

- K.K. Gan

## ATLAS Pixel Opto-link

- US ATLAS Review

- K.K. Gan

## Opto-package

- coupled VCSEL power > 300 W @ 10 mA
- VCSEL tolerance:
- 50 m in z (along fibre)
- 25 m in r (transverse to fibre)

- US ATLAS Review

- K.K. Gan

## Opto-package Designs

- 8 silicon/alumina pieces
- use silicon mirror for 450  light reflection
- high cost
- Taiwan
- 3 G-10 pieces
- cleave fibre at 450
- fibers permanently attached: need voliton connector
- low cost
- OSU
- 2 pieces
- cap with fibers can be attached to package at end of module assembly
- low cost

- US ATLAS Review

- K.K. Gan

## OSU Design

- use precisely fabricated cap and base for alignment
- simple two-piece design for mass production and cost reduction
- 
- cap
- 2 holes for fibers
- base
- deposit gold traces for wire bonding, VCSEL and PIN placements

- US ATLAS Review

- K.K. Gan

## Base and Cap

- US ATLAS Review

- K.K. Gan

## Cap and Base Prototypes

- material tested: aluminum silicate and macor
- difficult to obtain consistent precision
- 
- redesign base with square corners for ease of fabrication by Hybrid-Tek
- alumina sheet ground to proper thickness and cut into strips
- have produced bases with precision within specification
- 3D traces have good connectivity
- fabricate cap with Ultem (polyetherimide) for radiation tolerance (10 Grad)
- use manual micro mold injection to save development time
- can fabricate several quality caps per hour

- US ATLAS Review

- K.K. Gan

## Prototype Result

- VCSELs have fast rise and fall time: < 1 ns
- PINs have good responsitivity: 0.5 A/W
- coupled power > 300 W in both VCSELs simultaneously
-      for 8 packages with different combinations of bases and caps
- demonstrated feasibility of fabricating high precision caps and bases
- no cross-talk between VCSEL and PIN above 20 

- US ATLAS Review

- K.K. Gan

## Cap with Precisely Fabricated Cavity

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- K.K. Gan

## Base with PIN and VCSELs

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- K.K. Gan

## Completed Opto-package

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- K.K. Gan

## Slide 13

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- K.K. Gan

## no cross talk above 20 A

- no cross talk above 20 A

- US ATLAS Review

- K.K. Gan

## Summary on Opto-package

- precision bases with 3D traces of good connectivity fabricated
- precision caps fabricated
- packages produce optical power above specification
- 
- negligible cross-talk between VCSEL and PIN
- ability to produce precise die placement jig is a concern
- required six trials (one week) for current jig

- US ATLAS Review

- K.K. Gan

## Opto-hybrid Board

- contains 6 sets of opto-pack, VDC, and DORIC
- electrical signal to/from module channel through 60-pin connector
- layout to serve 7 modules is ready
- will convert to serve 6 modules
- first submission will use FR-4 for cost saving
- 2nd and 3rd prototypes will use BeO
- board is compatible with Taiwan opto-pack

- US ATLAS Review

- K.K. Gan

## Opto-hybrid

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- K.K. Gan

## Slide 18

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- K.K. Gan

## Slide 19

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- K.K. Gan

## Conclusions

- no major technical challenge in opto-hybrid board fabrication
-        compatible with Taiwan opto-pack
-        experience in opto-pack prototyping is very useful
-           for mounting opto-packs on opto-hybrid board

- US ATLAS Review

- K.K. Gan