r&d work on gigabit optical link for atlas id readout upgrade at smu

Report: R&D work for ID upgradeMay 3, 2007 @ UCSCJ.Ye @ SMU

R&D work on gigabit optical link for ATLAS R&D work on gigabit optical link for ATLAS ID readout upgrade at SMUID readout upgrade at SMU

Objectives: Evaluate the GOL chip in an optical link system and perform characteristic

measurements (jitter, bit error rate, etc). (done in 2006) Irradiate the GOL up to 100 Mrad and measure SEE, TID. (done in

Jan./Feb.2007)

Continue evaluation on link components in radiation : VCSELs, fibers (in progress in 2007)

Work with LBNL and UCSC to develop a 1.6 gigabit optical link to readout the test stave. (in progress in 2007)

Participating in the development of a baseline optical link for the ID readout upgrade. Work with groups developing ABCNext, LOC, GBT and the Versatile link (module). (in progress for 2007 – 2009).

Manpower:One FTE in a team of three FTEs, two RAs and two faculty members.


Test results on the GOL in 2006 – 2007Test results on the GOL in 2006 – 2007 (1)(1)

1. The test system designed and constructed for in-lab and irradiation tests:

32 bits/40 MHz

16 bits/80 MHz

A big board for a small chip:For in-lab (BER, jitter and power-up schemes) and irradiation (gamma, proton and neutron) tests.The VCSEL is mounted 2 mm away from the GOL. The LC connector is 4×4 mm2 cross, and 50 mm boot length. The fiber is 1.6 mm OD.GOL: 13×13mm2×1.7mm, ~400 mW.The actual PCB space needed for in the actual application will be less than 20 mm × 30 mm (the red mark).

The upper 3U crate hosts boards in the beam (gamma or proton).The lower 6U crate hosts controlling and DAQ boards. The master PC can be placed 40 meters away, connecting with USB.

LabVIEW based GUI.


Test results on the GOL in 2006 – 2007 Test results on the GOL in 2006 – 2007 (2)(2)

2. In-lab characterization tests on the GOL:o Bit Error Rate (BER):

• Tr-225ps, Tf-245ps.• Eye mask test.

o Power-up schemes studied and found to be reliable.o The jitter tests:

• GOL reference clock jitter transfer function:

Clock jitter cutoff at about 1 MHz. Complies with the adapted IEEE standards.Low frequency jitter (noise) sourceat the system level needs to bewatched for.

• GOL-TLK optical link jitter tolerance:Jitter tolerance complies with the IEEE standard.This plot specifies the transmitterreference clock jitter to be below the blue line to achieve a BER less than 10-12.

BER > 10-12

BER < 10-12


Test results on the GOL in 2006 – 2007 Test results on the GOL in 2006 – 2007 (3)(3)

3. Irradiation tests on GOL:o Source: 230 MeV proton.o Tests: TID up to 106 Mrad (Si); SEE cross section (probability).o Results:

TID:• No supply current increase during the irradiation. GOL functions error free

immediately after the beam is off, very small change in eye diagram and jitter. survives the TID test of 106 Mrad(Si)

SEE: very small SEE cross section. Flux

(protons/cm2/s)Fluence

(protons/cm2)Dose

(Mrad(Si))SEU events

LoL Bit ErrorCross-section (cm2)

LoL Bit Error

< 6 x 108 1 x 1011 5 x 10-3 0 0 < 2.7 x 10-11 < 2.7 x 10-11

1 x 109 3.7 x 1012 0.2 1 0 2.7 x 10-13 <2.7 x 10-13

2 x 1010 7.6 x 1013 4 17 4 2.2 x 10-13 5.3 x 10-14

5 x 1011 1.9 x 1015 100 200 20 1.1 x 10-13 1.1 x 10-14

Eye diagram: before (left) and after

Before irradiation After irradiation

Jitter Components Tx clk Serial Data Tx clk Serial Data

Random (RMS) 10.2ps 4.6ps 11.1ps 4.7ps

Deterministic (Pk-Pk) 67.6ps 55.6ps 67.0ps 57.9ps

Total@BER-14 196.1ps 106.7ps 211.7ps 111.8ps


Test results on VCSEL and fiber in 2006 – 2007Test results on VCSEL and fiber in 2006 – 2007

4. Tests on fiber and VCSEL.The Fiber:o Infinicor SX+ 50/250m/1.6mm MM

10G fiber from Corning. Germanium doped.o Tested wit Gamma (Co-60) and

Proton (230 MeV, 1.9×1013 proton/cm2). o Very small light loss at low flux (dose rate).

Big loss at high flux but anneals very quickly (within 1 hour) back.

o Very promising for LHC upgrade.o More tests with gamma needed.

The VCSEL:o Two HFE6192-562 (10G LC w/ 50 ohm flex) from Finisar tested .o Irradiated with 230 MeV proton, 1.9×1013 proton/cm2. o The VCSELs are biased during irradiations.o Eye diagram – see plots and table.o Looks very promising but more tests needed.

VCSELBefore irradiation After irradiationRise/fall time (ps)

O-power (W)

Rise/fall time (ps)

O-power (W)

L1 114/130 431 110/128 133L2 120/132 450 122/132 295

L1, before irradiation

L1, after irradiation


Conclusions on the GOL, VCSEL and fiber evaluationConclusions on the GOL, VCSEL and fiber evaluation

1. GOL complies with the adapted (to 1.6 Gbps) IEEE standard for Gigabit Ethernet (1.25 Gbps).

2. GOL is tested to be rad-resistant up to 106 Mrad (Si).3. The SEE probability is measured to be 1.1×10-13 for link

frame loss and 1.1×10-14 for single bit flip. The GOL chip is a good candidate for 1.6 Gbps optical link,

rad-hard to the ID requirement.

4. We have preliminary candidates for the VCSEL and the fiber.


Plans for 2007 and 2008Plans for 2007 and 2008

1. Issues on a gigabit optical link architecture:o Rad-hard serializer + TOSA (driver, VCSEL),o Rad-hard fiber,o Reference clock jitter control (cleaning),o Input data bit-to-bit skew control,o Reliability and single point failure prevention.

2. To address the above issues, we plan to:o Collaborate with LBNL and UCSC to construct a GOL based prototype

link to readout the test stave.• To study gigabit link system issues with the ABCNext (ABCD for

now) upstream electronics, with the QPLL clock jitter cleaner.• A dual link system will be investigated to address

The single point failure,The SEE

• CERN QPLL chip will be used as the clock cleaner.o Do more irradiation tests on fiber and VCSEL to identify candidates

for a multi-gigabit optical link for SLHC ID readout upgrade.o Carry out reliability tests on the GOL, TOSA to provide info about the

redundancy in the link. o Investigate the LOC and the GBT as the serializer chip when they

become available for higher bandwidth link.


Our design of the GOL based prototype optical link Our design of the GOL based prototype optical link (1)(1)

conn

ecto

r

LVD

S

CM

OS

Delay line + QPLL

GOL

TOSA

VCSEL

fiber

fiber

data (32)

clock

Control logic

The transmitter board. The output can be chosen to go through TOSA (CERN rad-hard versatile link) or a VCSEL to avoid failures in the optical device and fiber.The delay line in the data bus is used to address the bit-to-bit skew problem. In ABCnext, this delay will be implememented.

Del

ay li

nes


Our design of the GOL based prototype optical link Our design of the GOL based prototype optical link (2)(2)

fiberROSA

PIN+TIA+LA

TLK2500

conn

ecto

r

CM

OS

L

VD

S

1:2

deM

UX data (32)

clock

The receiver board


Budget (for 2008)Budget (for 2008)

manpower One FTE @ $55k/yr, w/ 25% benefit $68.75k

M&S PCB fab. + assembly + components $10k

Travel For gamma irradiation tests only $5k

Others Reliability test $0

Total With SMU 45.5% overhead $121.85k

r&d work on gigabit optical link for atlas id readout upgrade at smu

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