1. Next generation rad-hard links
Carmelo Scarcella
EP-ESE-BE

2. Outline Versatile link overview Rad-hard transceiver – VTRx Timeline
“Build of material”
Specs
Conclusions

3. Versatile link Parameter Value Units Max Bit Rate 4.8 Gbps Wavelength
Optical Rx
Optical Tx
Optical Tx
Optical Rx
Front-end
Radiation hard
Transceiver - VTRx
Passive optics
Optical fibers
And connectors
Back-end
Custom off-the-shelf
transceiver
Parameter
Value
Units
Max Bit Rate
4.8
Gbps
Wavelength
1310 nm
Total ionizing dose (TID) 10
kGy
Fluence
5 · 1014
n/cm2 MeV neutrons

4. Single-mode Versatile Link Transceiver - VTRx
Laser Diode
TOSA TX
PIN + TIA
ROSA RX
Laser Driver
connector
edge
I2C
PCB
InGaAs Photodiode
Transimpedance amplifier (TIA)
Laser
Laser driver
Mechanical latch and PCB
Beam Instrumentation Group orders
BE-BI-BL: 500 modules
BE-BI-QP: 500 modules
More modules are needed during CERN LS3!!!

5. Project time-schedule
Single-mode VTRx
development
Single-mode VTRx
installation

6. Receiver Optical Sub-assembly - ROSA
InGaAs Photodiode
Off-the-shelf component
Transimpedance amplifier (GBTIA)
Custom rad-hard ASIC
Assembling of ROSAs for first generation of Single-Mode VTRx is ongoing
Add parts for the new generation of VTRx to this production stage?
Laser Diode
TOSA TX
PIN + TIA
ROSA RX
Laser Driver
connector
edge
I2C
PCB

7. Transmitter Optical Sub-assembly - TOSA
Laser diode
Obsolete part
Need to identify a replacement
Market survey has been done and test samples procured
Radiation tolerance is the main selection parameter
Laser Diode
TOSA TX
PIN + TIA
ROSA RX
Laser Driver
connector
edge
I2C
PCB

8. Laser driver Custom rad-hard ASIC – GBLD V4.2
Max data rate of 5 Gbps Limiting factor for the link speed!
Ibias = 2 ÷ 43 mA Imodulation = 4 ÷ 24 mA
Able to drive edge-emitting Lasers and VCSELs
Next Laser driver generation will drive VCSELs only
lower current and data rate 10 Gbps
Laser Diode
TOSA TX
PIN + TIA
ROSA RX
Laser Driver
connector
edge
I2C
PCB

9. Mechanical latch and PCB
Injection molding mechanical latch
custom design based on TOSA and ROSA mechanical constrains
a new design and mold might be needed to suit the new TOSA
Electronic board might need revision

10. Link specs Radiation tolerance? Temperature range?
Max link length & breakpoint number?
Magnetic field?
Input needed from Beam Instrumentation Group!
Rough estimation for number of modules?

11. To do list Select a new LASER die Modify latch and PCB
Procurement of photodiodes before they became obsolete
Availability of TIAs and Laser drivers

12. Conclusions Project analysis
Single-mode TOSAs procured from different suppliers
Irradiation test planned for April 2017
Laser diode functional evaluation ongoing
Specs to be defined based on Beam Instrumentation Group requirements