Passive Optical Networks for Timing-Trigger and Control Applications in High Energy Physics Experime...
Download
1 / 40

17 th IEEE Real Time Conference, Lisboa , May 24-28, 2010 - PowerPoint PPT Presentation


  • 95 Views
  • Uploaded on

Passive Optical Networks for Timing-Trigger and Control Applications in High Energy Physics Experiments. 17 th IEEE Real Time Conference, Lisboa , May 24-28, 2010. I. Papakonstantinou, C. Soos, S. Papadopoulos, J. Troska, F. Vasey, S. Detraz, C. Sigaud, P. Stejskal, S. Storey

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about '17 th IEEE Real Time Conference, Lisboa , May 24-28, 2010' - tillie


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
17 th ieee real time conference lisboa may 24 28 2010

Passive Optical Networks for Timing-Trigger and Control Applications in High Energy Physics Experiments

17th IEEE Real Time Conference, Lisboa, May 24-28, 2010

I. Papakonstantinou, C. Soos, S. Papadopoulos, J. Troska, F. Vasey, S. Detraz, C. Sigaud, P. Stejskal, S. Storey

PH-ESE CERN

ioannis.papakonstantinou@cern.ch


Outline
Outline Applications in High Energy Physics Experiments

  • PON Definition

  • Motivation

  • Prototype Demonstrator

  • Protocol of Communication

  • Transceiver Design

  • Prototype characterization

  • Future work and Conclusions


Outline1
Outline Applications in High Energy Physics Experiments

  • PON Definition

  • Motivation

  • Prototype Demonstrator

  • Protocol of Communication

  • Transceiver Design

  • Prototype characterization

  • Future work and Conclusions


Pon definition
PON Definition Applications in High Energy Physics Experiments

OLT

  • PON is a Point-to-MultiPoint (P2MP) optical network with no active elements in the signal’s path

  • Upstream and Downstream are multiplexed into ONE fiber

  • In the downstream direction (Master→Slave) PON is a broadcast network

  • In the upstream direction a number of slaves share the same transmission medium

  • Commercial PONs run at 1.25 Gb/s or 2.5 Gb/s but 10Gb/s standards have just emerged

  • Cost: ~900$/OLT cost ONU ~90$/ONU. Gigabit Ethernet TRXs

Master

Downstream

D2

D1

U1

U2

UN

Upstream

U1

U2

UN

Slave1

...

Slave N

Slave2

ONUs


Outline2
Outline Applications in High Energy Physics Experiments

  • PON Definition

    • Motivation

  • Prototype Demonstrator

  • Protocol of Communication

  • Transceiver Design

  • Prototype characterization

  • Future work and Conclusions


Motivation
Motivation Applications in High Energy Physics Experiments

  • LHC P2MP links are used to transmit timing-trigger-control information

  • Current TTC system is unidirectional (optically)

  • Advantages of proposed implementation

    a) It is based exclusively on COTS components

    b) The inherent bidirectionality of PONs means that TTC and throttle/busy networks can be merged simplifying the infrastructure and reducing the amount of connectors and cabling in the counting rooms

    c) the bidirectionality of the link can be also exploited to measure and to correct for latency variations

    d) FPGA based implementation offers a simple path to upgradability

    e) It is a potentially clock free solution


System specifications
System Specifications Applications in High Energy Physics Experiments


Outline3
Outline Applications in High Energy Physics Experiments

  • PON Definition

  • Motivation

    • Prototype Demonstrator

  • Protocol of Communication

  • Transceiver Design

  • Prototype characterization

  • Future work and Conclusions


Pon demonstrator
PON Demonstrator Applications in High Energy Physics Experiments

  • 2 slave nodes have been implemented

  • One master and one slave node are implemented on the same Virtex 5 platform.

  • The second slave node is implemented on a Spartan 6 platform

  • Master and slave nodes are in different transceiver tiles and clocked by uncoupled sources

TTCrx

TTCex

TTCrx

OLT/TTCex

ONU1/TTCrx

ONU2/TTCrx


Outline4
Outline Applications in High Energy Physics Experiments

  • PON Definition

  • Motivation

  • Prototype Demonstrator

    • Protocol of Communication

  • Transceiver Design

  • Prototype characterization

  • Future work and Conclusions


Downstream frame
Downstream Frame Applications in High Energy Physics Experiments

  • Synchronous transmission of super-frames with a period of 1625ns = 65*25ns at 1.6Gbit/s

  • Comma, “K”, character for frame alignment and for sync

  • T character carries trigger info. “F” for trigger protection or other functions

  • D1 and D2 carry broadcast or individually addressed information depending on the first bit of the D1 byte.

  • “R” field contains the address of the next ONU to transmit

  • 590.8 Mb/s are available for data downstream

Slave1

Slave2

Slave64

TWEPP 2009 21-25 Sep. Paris – Optoelectronics and Links Session


Upstream frame
Upstream Frame Applications in High Energy Physics Experiments

  • Slave N1 receives an R character with its address and switches its laser ON

  • IFG between successive emissions allows to master receiver to adapt to different bursts

  • Channel arbitration is a logic built-in in the OLT

  • Total BW 800Mb/s, 7.7 Mb/s are available per Slave node for pure data


Outline5
Outline Applications in High Energy Physics Experiments

  • PON Definition

  • Motivation

  • Prototype Demonstrator

  • Protocol of Communication

    • Transceiver Design

  • Prototype characterization

  • Future work and Conclusions


Olt transmitter
OLT Transmitter Applications in High Energy Physics Experiments

Clk ref

  • Latency issues at the Tx arise at clock domain crossing points

  • Gear Box logic ensures correct transition from 40MHz to 80MHz in the Tx-PCS

  • It is particularly important to bypass any elastic buffers in the data path

  • In GTX Tx this is achieved by advanced mode which forces PMA PLL to phase align XCLK and RXUSRCLK clocks

40MHz

TI PLL

Virtex- 5GTX Transmitter

80MHz

40MHz

80MHz

DCM

PMA PLL

80MHz RXUSRCLK

80MHz XCLK

800MHz

Frame Generator / Gear Box

8B/10B

16

20

F

I

F

O

P I S O

Input

...

...

1.6Gb/s

2

2

Output

1

1

clock domain crossing

Tx-PMA

Tx-PCS


Onu receiver
ONU Receiver Applications in High Energy Physics Experiments

Clk ref

REFCLK

80MHz

Virtex- 5 GTX Rx or Spartan-6 GTP Rx

  • 80 MHz parallel clk can lock on any of the 20 first edges of the 800 MHz serial clk

  • That affects the order with which parallel data are exiting the SIPO

  • By fitting “K” characters into the frame and identifying them in a Barrel shifter we can predict the starting point of the XCLK

PMA PLL

800MHz

Rxin

1.6Gb/s

Retimed

Barrel Shifter

20

S I P O

CDR

2

...

Input

800 MHz Serial

1

80 MHz XCLK

DIV

1÷10

Shift value

DCM

ctrl

Phase corrected 40MHz

Phase corrected 40MHz

80MHz

RXUSRCCLK

DCM

:2

Comma detect logic

180° 40MHz

800MHz clk

. . .

17

18

19

0

1

2

3

80MHz clk


Outline6
Outline Applications in High Energy Physics Experiments

  • PON Definition

  • Motivation

  • Prototype Demonstrator

  • Protocol of Communication

  • Transceiver Design

    • Prototype characterization

  • Future work and Conclusions


Latency map
Latency Map Applications in High Energy Physics Experiments

OLT

ONU

2.2 ns

2.1 ns

ONU TRx

FPGA

FPGA

OLT TRx

GTX Receiver

GTX Transmitter

bias

Tx+

Rx+

Tx+

Rx+

Tx-

Rx-

Tx-

Rx-

137.5 ns

75ns

5 ns/m


Latency stability measurements
Latency Stability Measurements Applications in High Energy Physics Experiments

  • Histogram of 100 reset cycles

  • TI PLL power cycle →Tx reset→ Rx reset

  • Stability to within <150ps

  • But a better look-up-table implementation will give better results


Jitter map
Jitter Map Applications in High Energy Physics Experiments

After PLL

RMS: <10 ps

Ref 40 MHz

Ref clk

RMS: 3.17 ps

TI PLL

CDCL6010

After DCM

RMS: 36.72 ps

TI PLL

Out 40 MHz

After TI PLL

RMS: 4.48 ps

Before DCM

RMS: 17.33 ps

80 MHz

OLT

ONU

GTX Receiver

FPGA Design

DCM

bias

Tx+

Rx+

Tx+

Tx-

Rx+

BS

Rx-

Tx-

Rx-


Latency monitoring
Latency Monitoring Applications in High Energy Physics Experiments

Feeder fiber monitoring

Full Ranging

OLT

ONU

OLT

φ

Downstream

Downstream 1490nm

D2

D1

D2

D2

D1

D1

U1

D1

Upstream

U1

D2

U2

Upstream 1310nm

U2

ONU1

ONUN

...

ONU1

ONUN

...

Rx

Rx

Tx

Tx


Outline7
Outline Applications in High Energy Physics Experiments

  • PON Definition

  • Motivation

  • Prototype Demonstrator

  • Protocol of Communication

  • Transceiver Design

  • Prototype characterization

    • Conclusions


Summary
Summary Applications in High Energy Physics Experiments

  • A passive optical network for TTC applications has been successfully demonstrated

  • Fixed and deterministic latency has been achieved in the direction of the trigger transmission within ±150ps

  • Recovered clocks had <10ps RMS jitter with external PLLs

  • Network is bidirectional allowing for the slave nodes to provide the master with feedback

  • Also allow for latency variation detection and correction


Acknowledgements
Acknowledgements Applications in High Energy Physics Experiments

This work was supported in part by the ACEOLE, a Marie Curie mobility action at CERN, funded by the European Commission under the 7th Framework Programme


17 th ieee real time conference lisboa may 24 28 2010

Questions? Applications in High Energy Physics Experiments

ioannis.papakonstantinou@cern.ch


Back up slides
BACK UP SLIDES Applications in High Energy Physics Experiments


Pons in osi architecture
PONs in OSI Architecture Applications in High Energy Physics Experiments

  • PONs reside in the last two layers in the OSI architecture namely

  • Data link layer which is responsible for the access to the medium and for error correction

  • Physical layer which is responsible for transmitting and receiving the information

  • In GPON terminology the two layers are called: G-Transmission Convergence (GTC) and Physical Media Dependent (PMD)

  • EPON modifies MAC layer to allow for bridging data back to the same port


System power budget
System Power Budget Applications in High Energy Physics Experiments

Master

Downstream

Upstream

Slave1

...

Slave N

Slave2


Transceivers for pons
Transceivers for PONs Applications in High Energy Physics Experiments

EPON

GPON (1.24 Gb/s)

  • GPON has far more stringent requirements than EPON

  • For this reason GPON components are in general more expensive than EPON

  • OLT needs a 1490 nm laser (usually DFB-DBR)

  • Burst Mode Receiver

  • ONU needs 1310 nm F-P laser with burst mode laser drivers

  • PIN diode or APD at 1490 nm

ONU

OLT

Coarse WDM

Coarse WDM

1490 nm

DFB TOSA

ROSA (PIN)

Post-amp

CDR

LD

1310 nm

AGC+ CDR

Post-amp

BM ROSA (APD)

Optical signal

F-P TOSA

BM-LD

Electrical signal


Burst mode rx decision threshold set
Burst Mode Rx Decision Threshold set Applications in High Energy Physics Experiments

APD

LA

Data Out

TIA

+

-

R

Vref

Vref

Vref

C

Reset

Peak Detection Circuit


P2mp timing parameters
P2MP Timing Parameters Applications in High Energy Physics Experiments

TWEPP 2009 21-25 Sep. Paris – Optoelectronics and Links Session


Barrel shifter
Barrel Shifter Applications in High Energy Physics Experiments

REFCLK

PMA PLL

Clk ref

80MHz

800MHz

. . .

1/10

20

b16

S I P O

Barrel Shifter

CDR

D I V

2

b18

. . .

Rxin

1.6Gb/s

1

b17

RXRECCLK

“K”

80MHz

b0

b3

b1

b2

b4

b5

800MHz clk

80MHz clk


Slave rx latency barrel shifter
Slave Rx Latency, Barrel Shifter Applications in High Energy Physics Experiments

bs = 0

bs = 5

bs = 10


Olt tx gear box
OLT Tx – Gear Box Applications in High Energy Physics Experiments

40MHz

TI PLL

x2

x1

80MHz

REF

40MHz

40MHz

R/K/T/F

D1/D2/T/F

TXUSRCLK

IscharK

32

16

...

...

Frame Generator

Gear Box

2

2

80MHz

(o)

(o)

(e)

(e)

1

1

IscharK

(o)

(e)


Onu rx comma detect

Comma Detect Logic Applications in High Energy Physics Experiments

ONU Rx – Comma Detect

0

180

Barrel Shifter

EN

20

EN

20

Rearranged data

...

1

...

1

80MHz

RXUSRCCLK

K?

K?

Shift value

DCM

ctrl

Comma detect logic

Phase corrected 40MHz

DCM

:2

0

B

90

B

40 MHz

180

B

270

0

T/F

R/K

180


Upstream frame1
Upstream Frame Applications in High Energy Physics Experiments

  • Slave N1 receives an R character with its address and switches its laser ON

  • IFG between successive emissions allows receiver to adopt between bursts

  • Upstream contains 32 bytes of <5555> for CDR followed by two SFD, <D555>, bytes for frame alignment

  • A 2 byte address field and data are following

  • Channel arbitration is a logic built-in at the OLT

  • Total BW 800Mb/s, 7.7 Mb/s are available per Slave node for pure data

. . .

K

Addr

Data

5555

Data

32 B

2 B

2 B

90 B


Olt burst mode receiver
OLT Burst Mode Receiver Applications in High Energy Physics Experiments

REFCLK

PMA PLL

Clk ref

Rxin

20

Oversampling x5

20

S I P O

800Mb/s

2

2

1

1

Δφ

Slave1

Slave2

0

X

1

1

1

1

1

0

0

0

0

0

1

1

1

1

1

0

0

Samples


Upstream frame 2
Upstream frame (2) Applications in High Energy Physics Experiments

  • Dynamic range (Pslave1/Pslave2) affects IFG and thus available upstream BW/slave

  • It also affects the period between successive transmissions

Slave1

Slave2

Slave1

Slave2

IFG

24/11/2009


Future pon
Future PON Applications in High Energy Physics Experiments

  • Tri-band PONs

  • WDM PONs


Tri band pons
Tri-Band PONs Applications in High Energy Physics Experiments

1550 nm Tx (trigger)

  • Tri-band PON transceivers utilize 1440nm band

  • They can be used in our context to separate the trigger from the control information

  • That can simplify protocols of communication and complexity at the OLT

Master

1440 nm Tx (control)

1310 nm Rx

Slave2

Slave1

1310 nm Tx

1310 nm Tx

1440 nm Tx

1440 nm Rx

1550 nm Rx

1550 nm Rx


Wavelength division multiplexing pon
Wavelength Division Multiplexing PON Applications in High Energy Physics Experiments

OLT

RN

ONUs

WDM Tx

  • In a WDM PON scenario each channel (or channel group) is assigned one wavelength upstream and one downstream for communication with OLT

  • Benefits are higher bandwidth per channel, loss is independent from splitting ratio, less complicated scheduling algorithm at OLT, easy expansion, better delivery of services

  • Main disadvantage is the need for expensive WDM components such as AWGs, filters, tunable lasers / laser arrays / laser per ONU, broadband receivers etc

  • “Colorless” WDM PONs are developed to tackle cost issues

λ1

Receiver

Band A

SLED

λ1

λ1, λ2, … λ16

λ17

λ17, λ18, … λ32

RSOA

3 dB

Coarse WDM

λ17

CW

1 x 16 AWG

WDM Rx

λ16

λ17, λ18, … λ32

Receiver

Coarse WDM

λ16

Modulated

λ32

Upstream band

REAM

Downstream band

Coarse WDM

Band B

λ32

Receiver Array

DEMUX

λ