1. jgimenoIWM-12/1/2004 Fiber Optic module 1 STUDIES AND DEVELOPMENT OF A FIRST FIBER OPTIC MODULE PROTOTYPE Javier Gimeno Vicente

2. IWM-12/1/2004 Fiber Optic module2 jgimeno CONTENTS  Why a Fiber Optic module?  Characteristics of the link Attenuation: link between two BICs Optical power budget analysis  Optical components  “Detection and switch”  TESTS BIDI MODULE solution TRANSCEIVER MODULE solution ELED or “Agilent” solution DISCRETE BIDI solution  Conclusions  Future works

3. IWM-12/1/2004 Fiber Optic module3 jgimeno Why a Fiber Optic module? Beam Permit Loops We don’t transmit data  10MHz control signal Freq = OK No freq. = beam dump

4. IWM-12/1/2004 Fiber Optic module4 jgimeno Why a Fiber Optic module? Responsible of receiving the Beam Permit signal (10MHz if OK), interrupting if a client activates a beam dump request, and transmitting the resulting signal. CONSTRAINTS: fast, simple and RELIABLE. Fast requirements: to convert the light into voltage  to interrupt (switch) the signal  to convert the signal into light.

5. IWM-12/1/2004 Fiber Optic module5 jgimeno Characteristics of the link (1/2)  BIC layout in the LHC

6. IWM-12/1/2004 Fiber Optic module6 jgimeno Characteristics of the link (2/2)  Characteristics fixed and determined by: Fiber Distance between BICs Connectors  All the links must fulfil the optical power budget rule  Single mode suitable for 1310nm and 1550nm wavelengths Attenuation: 0.5dB/Km (worst case) Degradation during time negligible Typical delay of 5ns/m (worst case: half LHC (~13.5Km)  ~67.5µs) max.: 3.3Km (BICs in different IPs) min.: some meters (BICs in the same room) Any possible Recommended and used at CERN: E2000/APC Losses: 0.5dB in each connector (worst case)

7. IWM-12/1/2004 Fiber Optic module7 jgimeno Attenuation: link between two BICs  Minimum attenuation: BICs in the same room  Maximum attenuation: BICs in different IPs  Safety margin  min. 2dB  typ. 3dB (Honeywell…)

8. IWM-12/1/2004 Fiber Optic module8 jgimeno Optical power budget analysis Optical power margin rule  It determines the optical power characteristics of the transmitter and receiver

9. IWM-12/1/2004 Fiber Optic module9 jgimeno Optical components (1/3)  Types  Electrical characteristics DISCRETE: - Analog interface - Development of the analog to digital conversion MODULE: - Optical component + digital interface  Optical characteristics OPTICAL TRANSMITTER: - LED: Surface-emitting LED, Edge-emitting LED (ELED), Superluminescent LED (SLED)… - LASER: Laser Diode (LD), Vertical Cavity Surface-emitting Laser (VCSEL)… OPTICAL RECEIVER: - PIN (positive-intrinsic-negative) photodiode - Avalanche photodiode (APD)

10. IWM-12/1/2004 Fiber Optic module10 jgimeno Optical components (2/3) *WDM: Wave Division Multiplex BIDIrectional TRANSCEIVER DETAIL TRANSCEIVER or TRANSMITTER AND RECEIVER: - Independent transmitter and receiver - 2 fibers to transmit and receive (same wavelengths) BI-DI TRANSCEIVER: - Transmitter and receiver in the same device - ONLY 1 fiber to transmit and receive (different wavelengths)  2 topologies using

11. IWM-12/1/2004 Fiber Optic module11 jgimeno Optical components (3/3) SOLUTIONCHARACTERISTICSCOMPANY BIDI MODULE SOLUTION 1 fiber to transmit and receiver BIDI module (standard package) ITEC Infineon TRANSCEIVER MODULE SOLUTION 2 fibers to transmit and receiver Module component (standard package) ITEC ELED or “Agilent” SOLUTION  2 fibers to transmit and receiver  Discrete components  Agilent design Agilent and PD-LD DISCRETE BIDI SOLUTION 1 fiber to transmit and receiver Discrete components Development of analog to digital interface Afonics OTHER SOLUTIONS S.I.Tech ONTi Eva Calvo Cypress  Selection

12. IWM-12/1/2004 Fiber Optic module12 jgimeno DETECTION and SWITCH (1/2)  Not complex (but must be RELIABLE!!): SWITCH: simple AND gate Frequency Detection “By edge”, using counters “By sample”, using a shift register to sample

13. IWM-12/1/2004 Fiber Optic module13 jgimeno DETECTION and SWITCH (2/2)  Proposed circuit for the TESTS  REGENERATION NO REGENERATIONREGENERATION + 1 source of 10MHz in the first BIC: if no RX signal (10 MHz)  no TX signal + TX signal depends on BEAM PERMIT SIGNAL and ENABLE signal ± Redundancy: FREQUENCY DETECT, but adds an extra-delay - Integrity of the 10 MHz signal has to be tested + Regeneration of the 10 MHz signal - 1 source in each BIC: no RX signal (10 MHz) ≠ no TX signal - TX signal depends only on TX ENABLE signal - Less reliable

14. IWM-12/1/2004 Fiber Optic module14 jgimeno BIDI MODULE Solution (1/3)  DESIGN: Very simple Digital conversion  Prototype board

15. IWM-12/1/2004 Fiber Optic module15 jgimeno BIDI MODULE Solution (2/3)  TESTS Without “detection and switch” Without attenuator, only fiber optic cable of 10m

16. IWM-12/1/2004 Fiber Optic module16 jgimeno BIDI MODULE Solution (3/3)  RESULTS: + BIDI MODULES (ITEC and Infineon) fulfil the optical power budget rule (minimum transmitter output power -15dBm / Receiver sensibility: -33dBm) - RECEIVERS PROBLEM: AGC in TIAs don’t allow the transmission of signal below ~100kHz  Not good “switch” from 10MHz to DC signal - Same results for TRANSCEIVER MODULE SOLUTION  CONCLUSION : SOLUTION(S) NOT GOOD TX RX SD TX RX SD

17. IWM-12/1/2004 Fiber Optic module17 jgimeno ELED or “Agilent” Solution (1/3)  DESIGN: Agilent design Simple but ELEDs quite expensive ELEDs board  standard package (it can be used with BIDI prototype board after some modifications)  Modified BIDI prototype board

18. IWM-12/1/2004 Fiber Optic module18 jgimeno ELED or “Agilent” Solution (2/3)  FIRST TEST: transmission, attenuation and detection  RESULTS: + PD-LD ELED with Agilent receiver fulfill the optical power budget rule (minimum transmitter output power -23dBm / Receiver sensibility: -33dBm) + Max. attenuation: 12dB + REGENERATION is not necessary + Lost of frequency correctly detected TX RX DETECT TX RX

19. IWM-12/1/2004 Fiber Optic module19 jgimeno ELED or “Agilent” Solution (3/3)  SECOND TEST: beam permit loop simulation  CONCLUSION : SOLUTION WORKING TX (BIC 1) ALARM (BIC 2) ReTX (BIC 2) DETECT (BIC 3) TX (BIC 1) ALARM (BIC 2) ReTX (BIC 2) DETECT (BIC 3)

20. IWM-12/1/2004 Fiber Optic module20 jgimeno DISCRETE BIDI Solution (1/2)  DESIGN: - Complex design (laser, very low analog signals, board design…) + Allow flexibility (selection of components, optical power…)  COMPONENTS: Discrete BIDI: Afonics (although lots similar) TX circuit: MAX3263 (laser driver, Maxim) RX circuit: SA5212 (TIA, Philips) + postamplifier (LT1016, Agilent board)

21. IWM-12/1/2004 Fiber Optic module21 jgimeno DISCRETE BIDI Solution (2/2)  RESULTS: + Design fulfill the optical power budget rule Transmitter output power: -27.5dB for “0” / -2.5dB for “1”  Adjustable Receiver sensibility: ~-30dB (R=0.5  A/  W  it depends also on electronics) - Must avoid receiver saturation - Integrity of the signal (fall/rise time) + More power  more margin of attenuation + Max. attenuation: 27.5dB (up to 50Km of fiber!!!!)  CONCLUSIONS: SOLUTION WORKING New board and more tests necessary BUT STILL IN PROGRESS

22. IWM-12/1/2004 Fiber Optic module22 jgimeno OTHER SOLUTIONS  S.I. Tech solution: Similar to Agilent solution (discrete components + analog to digital conversion) Don’t allow transmission of DC signals  ONTi: Chinese company with interests in working with CERN Development for us Good products and good price… but must be tested  Eva Calvo Design: DC transmission, reliability… and radioactivity Powerful transmitters (~1mW) Discrete components + special electronic circuit: analog circuit + ECL Tested and working  Cypress Transmitter circuit = Agilent design RX circuit with PECL postamplifier increases bandwidth

23. IWM-12/1/2004 Fiber Optic module23 jgimeno CONCLUSIONS  MODULE solutions simple but not working well  2 solutions working: ELED or Agilent solution  simple DISCRETE BIDI solution  it uses only 1 fiber and allows more margin of attenuation, but complex and more tests necessary  “Detection and switch” working  No regeneration necessary  detection only in the last module (should be tested)

24. IWM-12/1/2004 Fiber Optic module24 jgimeno FUTURE WORKS  Preparation of LHC simulation (using Agilent solution) with several modules in a loop  New board and more tests using DISCRETE BIDI solution  “Detection and switch”  how and where (Core or Fiber Optic module)?  Conclusions: more tests, new boards, more components (attenuators)… more money and more time!!  Still a lot of work before taking the FINAL DECISSION

25. IWM-12/1/2004 Fiber Optic module25 jgimeno QUESTIONS?