Optical Integrated Devices in Silicon On Insulator for VLSI Photonics

Transcription

1 Optical Integrated Devices in Silicon On Insulator for VLSI Photonics Design, Modelling, Fabrication & Characterization Piero Orlandi 1

2 Possible Approaches Reduced Design time Transparent Technology Shared Access Classical Optical Design Circuit-Based Approach All level knowledge Slow Process Not suitable for high complexity devices 2

3 Outline Introduction on SOI Platform and Motivations Classical Optical Design Grating Assisted Coupler (GAC) GAC-based Microring Circuit-Based Approach Reconfigurable Bandpass Filter Working principles Experimental Results Conclusions 3

4 3D Chip multiprocessor Scheme Introduction Photonic Integrated Circuits Lee at al., JSTQE,16(1),2010 MOTIVATIONS High Bandwidth Low Power Consumption SCOPE On the same chip with electronics: Inter & Intra chip Interconnection Transmit receive & process of high data rates signals Luxtera 4x10Gb/s WDM Transceivers, 2008 NEEDS Technological Platform: Very Large Scale Integration (VLSI) CMOS Compatible 4

5 Introduction Silicon On Insulator (SOI) Platform Very Large Scale Integration (VLSI) Submicrometre Waveguide Micrometre Bend Radius Low Losses CMOS Compatible Integration with electronics Theoretical low cost Needs for a shared platform 3μm 500nm PhD Work Passive devices for routing & add-drop functionality Reconfigurable Devices 5

6 Classical Optical Design Grating Assisted Couplers (GAC) & GAC-based microring resonator 6

7 3dB Bandwidth [GHz] Normalized Intensity R X Grating Assisted Coupler (GAC) Structure & Functionality Experiment vs. Modelling T X T D R D Exchange Bandwidth Wavelength [nm] Gap 200nm 220nm 240nm 100 4/6 8/ /15 Perturbation Amplitude [nm]

8 Normalized Intensity GAC Based Microring Resonator Drop= λ 2 Ring Resonator Add= λ m IN=λ 1, λ 2, λ 3,, λ N Trough=λ 1, λ m, λ 3,, λ N Free Spectral Range (FSR) is a Limit! Trough Drop FSR Wavelength [nm] 8

9 Normalized Intensity GAC Based Microring Resonator Idea Resonance over limited bandwidth Useful for single wavelength/channel extraction in WDM, Sensor application Wavelength [nm] 9

10 Intensity [a.u.] GAC Based Microring Resonator Experimental Result Wavelength [nm] 10

11 Intensity [a.u.] Intensity [a.u.] Intensity [a.u.] GAC Based Microring Resonator Wavelength [nm] Wavelength [nm] Wavelength [nm] 11

12 Circuit-Based Approach Reconfigurable Bandpass Filters Working Principles Experimental Results (Static & BER) 12

13 Variable Bandwidth Filter -φ r φ r L r K r K r L r P T K c ΔL= L r K c P C P IN P T P C 13

14 Intensity [a.u] Intensity [a.u] P IN MACH-ZEHNDER INTERFEROMETER k c L L U L k c Working Principles P T P C Optical Filters Discrete delayed (T) sum of the signal z T L U 1 e j Z-Transform Description L U P IN RING RESONATOR φ r L K U r P R DSP APPROACH P T P C Periodic Frequency Response P R Wavelength [nm] Wavelength [nm] 14

15 Intensity [db] Working Principles Symmetric Interleaver [Literature] III Order Butterworth Filter Maximally Flat Filter Response B db 3 FSR 2 /2 Power Coupling Coefficients K 8/ 9 1/ 2 r K c Wavelength [nm] NO Bandwidth Tunability 15

16 Intensity [db] Working Principles Symmetric Interleaver [Our Work] III Order Butterworth Filter =π/2 Maximally Flat Filter Response B db 3 FSR 2 Power Coupling Coefficients K 2/3 1/ 2 r K c Wavelength [nm] NOW Bandwidth Tunability 16

17 Intensity [db] Intensity [db] Intensity [db] Working Principles Device Simulations Phase Shift -> Bandwidth Reduction -> Lower Extinction Ratio r 2 r 2 3 r 3 4 Wavelength [nm] Wavelength [nm] Wavelength [nm] B db 3 FSR 2 B db 3 2FSR 3 B db 3 3FSR 4 17

18 Circuit-Based Approach Physical Structure Design Fabricated Couplers Couplers Look Up Table Bends Look Up Table Suitable Parameters Chosen Fabricated Bends 18

19 Circuit-Based Approach Physical Structure Design: Heater Optimized for Tuning Device Top view Ti + Au Cross Section Scheme NiCr 19

20 3dB Bandwidth [GHz] FSR = 200GHz Experimental Results Bandwidth Variation POWER CONSUMPTION Mean = 28.12mW Std Dev = 0.14mW 170GHz 23GHz P R1 P R2 [mw] 20

21 Normalized Intensity [db] Normalized Intensity [db] FSR = 200GHz P C Experimental Results Bandwidth Variation Bandwidth (BW) 170GHz 23GHz P T Wavelength [nm] Extinction Ratio (ER) Always < -16dB 170<BW<40GHz < -18dB Wavelength [nm] Insertion Loss (IL) at Minimum BW 0.6dB 21

22 f [GHz] FSR = 200GHz Experimental Results Central Wavelength Variation Shifted 3dB Bandwidth=FSR/5=40GHz Measurements Linear Fitting P f mw 0.3 GHz f FSR P mw P [mw] 22

23 FSR = 200GHz Experimental Results Experiment vs. Design DESIGN EXP. REL. ERROR FSR 200GHz 198GHz 1% Minimum T Bandwidth Minimum C Bandwidth 19GHz 23.1GHz 2% 19GHz 22.4GHz 1.7% Good Agreement! The approach Works 23

24 -log(ber) FSR = 200GHz Experimental Results BER vs. Filter Bandwidth [ASE Noise] 2 OSNR=23dB 3 OSNR=13dB B 3dB =170GHz B 3dB =50GHz B 3dB =23GHz 4 OSNR=16dB 5 6 OSNR = 23dB No effect on the signal at different Bandwidth OSNR = 16dB BER = 10-4 : 0.5dB P r gain BER = 10-9 : 0dB P r gain OSNR = 13dB BER = 10-4 : 1.25dB P r gain No variation between 50 and 23 GHz Pr [dbm] 24

25 CONCLUSIONS Modelling & technological experience has given good results Designed and realized a reconfigurable device of higher complexity First demonstration of the circuit based approach The presented work is the base for the third year activity => Building Block Optimization and Development PROJECT SAPPHIRE Shared Access Platform to PHotonic Integrated REsources Unità Coinvolte: Fonderia: 25

26 Conference Paper: P.Orlandi, M.Gnan, A.Samarelli, G.Bellanca, A.Melloni, R.M. de La Rue, M.Sorel, Modeling of Racetrack Resonator with Grating Assisted Coupling, XVIII th International Workshop on Optical Waveguide Theory and Numerical Modelling (OWTNM 10),, 9-10 April 2010, Cambridge, United Kingdom. A. Samarelli, P. Orlandi, M. Gnan, M. Sorel, R.M. De La Rue, A. Melloni, P.Bassi, "Grating Assisted Coupling in Microring Resonators", 15th European Conference of Integrated Optics (ECIO'10), 7-9 April 2010, Cambridge, United Kingdom, 2010 M. Gnan, P. Orlandi, A. Samarelli, G. Bellanca, A. Melloni, R.M. De La Rue, M. Sorel, P. Bassi, "Accoppiatori Assistiti da Reticolo Associati a Risuonatori ad Anello", XVIII Riunione Nazionale di Elettromagnetismo, Benevento, Italy, September 6-10, P.Velha, P.Orlandi, A. Samarelli, M.J. Strain, R.M. De La Rue, M. Sorel, P. Bassi, Microring resonator with wavelength selective coupling in SOI, The 8th International Conference on Group IV Photonics, September, London, United Kingdom, Crediti Acquisiti: 13 Mesi presso la Glasgow Univesity, Glasgow, United Kingdom: 60 Corso Solid State Electronics: 90 26