ASPICs for High Energy Physics Applications

1. ASPICs for High Energy Physics Applications Deepak Gajanana, Martin van Beuzekom Nikhef (National Institute for Subatomic Physics), Amsterdam XaveerLeijtens Eindhoven University of Technology, Eindhoven TIPP 2014 DGB et al.

2. Contents • Introduction • Generic Integration Technology (InP) • Example photonic ICs • Application in HEP experiments “An Application Specific Photonic Integrated Circuit integrates multiple optical components like sources, detectors, modulators etc. to save area, cost, power and add more functionality.” TIPP 2014 DGB et al.

3. Optical Waveguide m 2 m InP InGaAsP (1.3) m 0.6 m InP Scanning Electron Microscope (SEM) photograph Simulated mode distribution Materials could be Si, Binary, Ternary and Quaternary semiconductors. Indium Phosphide (InP) in combination with InGaAsP has advantages of making light sources, detectors and other circuits at 1550 nm (3rd generation telecom wavelength). TIPP 2014 DGB et al.

4. Waveguide fabrication process InP InGaAsP InP-substrate TIPP 2014 DGB et al.

5. Optical Waveguide human hair 75 μm TIPP 2014 DGB et al.

6. Arrayed Waveguide Grating (AWG) COBRA 1988 Smit, El. Lett, 1988 TIPP 2014 DGB et al.

7. MMI (Multi Mode Interference) Couplers Simulated pattern Experimentally imaged pattern Geometry of MMI-couplers Acts as power splitter/combiner. Various power ratios possible. TIPP 2014 DGB et al.

8. Mach Zehnder Switch Electric field changes the refractive index and hence the phase change of the optical wave TIPP 2014 DGB et al.

9. Photonic Integration with basic building blocks TIPP 2014 DGB et al.

10. Moore’s law for InP based PICs AWG-based devices TIPP 2014 DGB et al.

11. Moore’s law for InP based PICs Steenbergen 8x20 GHz WDM receiver PTL, 1996 TIPP 2014 DGB et al.

12. Moore’s law for InP based PICs Infinira 10x10 Gb/s WDM TRX 2005, 51 components TIPP 2014 DGB et al.

13. Moore’s law for InP based PICs Nicholes, MOTOR chip, OFC 2009, UCSB, 145 components TIPP 2014 DGB et al.

14. What Next? Commercial Advantages : Integrating more functionality, reducing size and reducing cost TIPP 2014 DGB et al.

15. Photonic IC Generic Integration platform Wafer fab Passive Phase Amplitude Polarization polarization converter waveguide phase modulator optical amplifier Application Powerful circuit simulation tools Powerful layout tools Photonics Design Manual A designer Multi-project wafer New design Designs from designers using the same platform Device back to users TIPP 2014 DGB et al.

16. History repeats itself… Silicon electronic ICs 1979 Indium phosphide photonic ICs 2012 MPC79, Lynn Conway TIPP 2014 DGB et al.

17. Examples of ASPICs and applications TIPP 2014 DGB et al.

18. External modulation technique • Modulators form the heart of the external modulation technique. InP Data arm Metal Laser input Light output Databar arm Mach Zehnder (MZ) Modulator TIPP 2014 DGB et al. CW Laser Continuous wave injection laser Digital read-out Chip Data Modulation Data acquisition & processing Optical modulator Photo diode Amplification

19. KM3NeT Detector concept • KM3NeT is a cubic kilometer neutrino telescope to be installed in the Mediterranean sea. For more information : www.km3net.org • High density data readout in remote submarine conditions. • Savings in area, cost and power motivate innovation, research and development of ASPICs. 320m TIPP 2014 DGB et al.

20. Concept for 80 Channels with Overlay DWDM* 1:20 1 λc @1.25 Gbps (Downstream Data) MOD + Drivers C - Band Lasers 20 x 1:4 λ1 C λ82 A1 LiNbO3 DOM D2 C - Band 50/50 80 λC CW C λ1-80 λ20 A2 DU-String 200 GHz DWDM OTDR Timing mode SMA LiNbO3 C1 VOA on/off SMA Junction Box λ1 80 λC @1.25 Gbps (Upstream Data) λ1 50-200 GHz APD A3 D1 C-Band Secondary Junction Box 100 km λ80 λ1-80 Shore station C-Band 1528-1568 nm L-Band 1568-1610 nm 1 2 C2 C2 C2 200 GHz 200 GHz λ82 PIN 50 GHz REAM …. …. λC 2xCu DOM λC1-80 λC1,5…80 + λC 82 *R&D on high density data readout. Explored as an option - Not used in the project presently. TIPP 2014 DGB et al.

21. InP based Colorless transceiver for KM3NeT • Continuous wave light (one of the 20 wavelengths separated at 200 GHz ) is separated from the slow control data. • The slow control data is detected by the photodiode and provided to the electronics. • The data from the sensors (effective data rate ~1.25 Gbps upstream) modulates the CW light and is reflected. • Aim is to integrate the building blocks (AWG, Modulator and PD) on a single die. 21 x 1 Reflective Modulator 1 x 21 20λ λx AWG λ1+λx AWG λ1 Electrical Domain PD DOM λx can be any of the 20 wavelengths will replace λ82 REAM PIN λC 2xCu DOM TIPP 2014 DGB et al.

22. InP based Colorless transceiver for KM3NeT Reflective circuit Reflective Modulator 1 x 21 λx SOA Reflective Modulator λ1+λx SOA AWG SOA λ1 Electrical Domain Test structures PD DOM λx can be any of the 20 wavelengths Transmissive circuit Transmissive Modulator 1 x 21 λx MMI SOA Transmissive Modulator λ1+λx SOA AWG SOA λ1 Electrical Domain PD DOM • AWGs channel spacing is dependent also on processing. With a loop back architecture, we remove the process variations on the AWG. • Transmissive architecture can be used for testing purposes. λx can be any of the 20 wavelengths TIPP 2014 DGB et al.

23. ASPICs for High Energy Physics Experiments • Modulators form the heart of the external modulation technique. • Little is known about radiation hardness of (InP) modulators. Ultimate goal : application at inner detectors at HL LHC. InP Data arm Metal Laser input Light output Databar arm Mach Zehnder (MZ) Modulator TIPP 2014 DGB et al. Detector – High Radiation environment Low radiation CW Laser Continuous wave injection laser Digital read-out Chip Data Modulation Data acquisition & processing Optical modulator Photo diode Amplification

24. Beam Test of InP based MZ modulators • Samples mounted in a shuttle that moves in and out of the 24 GeV/c proton beam at CERN to 1E12, 1E13, 1E14 and 1E15 p/cm2. • Vertex detectors at HL-LHC require a radiation hardness ~ 1E16 p/cm2. • The sample contains 22 modulators and measures 14mm × 4 mm Submount dimensions : 48 mm × 42 mm TIPP 2014 DGB et al.

25. Measurements of photonic chips • Measurements need precision alignment of chips and fibers. • Lensed fibers are used to couple and collect light. • Alignment of fibers are done manually using manipulators. Lensed fiber (9 u core) to be aligned to a 2 u wide 1u high waveguide. Bond wire TIPP 2014 DGB et al.

26. A Sample measurement Input power = + 6dBm @ 1550nm Y axis – Power (dBm) measured at the output. X axis – Voltage scan on one of the arms of the modulator. Imbalance Data arm Laser input Light output PD Databar arm InP Metal TIPP 2014 DGB et al.

27. WDM Modulator in the COBRA6 run MZ MZ MZ • MZ modulators: • 2 mm phase sections • Two AWGs: • GHz • GHz • Amplifiers: • small: modulation • large: gain • Test structures: • separate building blocks SOA SOA (DE)MUX (DE)MUX SOA SOA SOA SOA TIPP 2014 DGB et al. WDM modulator MZ modulators SOA Waveguide facet DC and RF electrical contacts Test AWG Test Modulator Test SOA

28. Preliminary Measurement results Optical Spectrum Analyzer (DE)MUX EDFA On Chip TMm arm Laser input Optical power meter Light output InP TMp arm Metal TIPP 2014 DGB et al. CS = 400 GHz FSR = 2400 GHz Crosstalk = 16 dB

29. Conclusions and Future • Photonic Integration is in it’s nascent stages and holds a ‘bright’ future. • Physics experiments can benefit from custom ASPICs. • Smaller, low power, more functionality, cheaper for large quantities • Generic Photonic Integration platform and access to MPW runs makes it easier for designing ASPICs for High Energy Physics. • Lot to be designed and measured, long way to go… TIPP 2014 DGB et al.