(Waveguide theory and) photonic circuit design
Transcript
(Waveguide theory and) photonic circuit design
2572-2 Winter College on Optics: Fundamentals of Photonics - Theory, Devices and Applications 10 - 21 February 2014 (Waveguide theory and) photonic circuit design A. Melloni Dip. Elettronica, Informazione e Bioingegneria Politecnico di Milano Italy Winter College on Optics: Fundamentals of Photonics Theory, Devices and Applications (Waveguide theory and) photonic circuit design A. Melloni Dip. Elettronica, Informazione e Bioingegneria Politecnico di Milano, Italy 7th Optoelectronics & Photonics Winter School: Physics and Applications of Optical Resonators – A. Melloni, Politecnico di Milano Waveguide theory and photonic circuit design - Waveguides (no theory…) - The role of index contrast in waveguides (survey of technologies, type of waveguides, index contrast…) - Bends and advanced topics on bends (the matched bend,...) - The dark side of integrated optical waveguides (backscatter, xtalk, losses, spurious modes, the (ng-neff) role….) - An excursus on ring resonators: history, spectral characteristics, applications, ... - Circuits: MZ, rings, higher order filters, delay lines, … - The circuit approach (building Blocks, Circuit simulators and few slides on Aspic, our circuit simulator that will be used at the end of the course for hands-on session). - The structure of generic foundries and available generic foundries 7th Optoelectronics & Photonics Winter School: Physics and Applications of Optical Resonators – A. Melloni, Politecnico di Milano Let’s combine rings A. Melloni from Ring to Rings… A. Yariv Caltech 1999 Microwave C. Madsen Bell Labs 1999 DSP R. Orta Politecnico Torino 1999 DSP A. Melloni Politecnico Milano 2002 Microwave V. Van Maryland Univ. 2006 Electronic/Microwave Books from I. Chremmos, O. Schwelb, D.G. Rabus, J. Hebneer, …. ORES School, Levico, 2013 A. Melloni from Ring to Rings… Parallel coupled bandstop filter Directly coupled bandpass filter (CROW) Ring-loaded Mach-Zehnder filter ORES School, Levico, 2013 A. Melloni Ring loaded Mach-Zehnder APF allows to shape the phase response 2(N+1) 1() 2() ORES School, Levico, 2013 A. Melloni FSR 2N Tunable bandwidth filter kc Lr kr Lr kr kc Bandwidth tunability is obtained by varying FSR = 200 GHz B = 23 GHz … 175 GHz IL < 0.6 dB ER > -18 dB ORES School, Levico, 2013 A. Melloni Coupled resonators ORES School, Levico, 2013 A. Melloni 8 Direct coupled cavities vs cascaded cavities Cascaded cavities (SCISSOR) Direct coupled cavities (CROW) -5 0 1 Transmission [dB] Transmission [dB] 0 -10 -15 2 5 -20 -25 -1 -0.5 0 0.5 Frequency ORES School, Levico, 2013 A. Melloni 1 -5 1 -10 -15 2 -20 -25 -1 -0.5 5 0 Frequency 0.5 1 Identical cavities ? 0 1 cavity Transmission [dB] -1 K=0.01 -2 1st order cavity d=/2 -3 B1 cavity=1.2 THz B=1.2THz -4 -5 -1500 -1000 -500 0 500 Frequency [GHz] BCROW=22.5 THz 1000 1500 100 cavities 0 0 -10 -10 Transmission [dB] Transmission [dB] 10 cavities -20 -30 -50 -1.5 -1 -0.5 0 0.5 Frequency [GHz] ORES School, Levico, 2013 -30 B=22THz -40 B=22THz -40 -20 1 A. Melloni 1.5 x 10 4 -50 -1.5 -1 -0.5 0 0.5 Frequency [GHz] 1 1.5 4 x 10 CROW impedance matching /4 -14 dB ZCROW 2n g ( ) 0 dB |H(f)|2 [dB] CROW ZW n eff Quarter-wave matching neff Frequency [GHz] ( / 4 ) n eff 2n g No impedance matching 11 ORES School, Levico, 2013 A. Melloni Impedance Matching (Apodization) ... ZCROW 2n g ( ) ZW n eff Quarter-wave matching neff ( / 4 ) n eff 2n g No impedance matching ORES School, Levico, 2013 A. Melloni Coupled ring resonators THROUGH K0 IN DROP f0 K1 ORES School, Levico, 2013 f0 K2 A. Melloni f0 f0 K3 f0 K2 K1 f0 K0 Progress in tuneable ringring-CROW 2009 2007 2008 2009 2010 56 μm N x 40 μm F. Morichetti et al., The first decade of coupled resonator optical waveguides: bringing slow light to applications. Laser & Photonics Reviews, 6: 74–96 (2012) ORES School, Levico, 2013 A. Melloni 8-rings Bandpass filters in SOI Intensity [dBm] Return loss: -15 dB; IL 0.5 dB; In-band ripple <0.2 dB; Off-band rejection >50 dB Wavelength [nm] A. Melloni 8-rings Bandpass filters in SOI -2 10 Waveguide λ=1536.27 nm λ=1550.42 nm -3 10 λ=1564.75 nm -4 BER 10 -5 10 -6 10 -7 10 -8 10 -9 10 -10 10 -11 10 -12 10 6 8 10 12 14 16 18 OSNR over 0.2 [nm] nm Wavelength A. Melloni 20 22 Thermal tuning NiCr Spin‐on glass SiO2 Thermal crosstalk hot ring Au wh h Si w =2.5 nm 28° C Si 0.7° C -20 Transmission [dB] cold ring 7 m =0.06 nm 8 rings -30 7 rings -40 6 rings 5 rings -50 4 rings -60 3 rings -70 1556 1558 ORES School, Levico, 2013 1560 1562 Wavelength [nm] A. Melloni 1564 1566 Tunable Delay lines A. Melloni On-Chip Tunable delay… not an easy task !!! out Electronic Microwave Photonics - let photons run around (coil of fiber) ORES School, Levico, 2013 – slow down photons A. Melloni Recirculating buffer Discrete delay line, Packet(s) delay and Buffer Technologies: 2007 Glass for the spire + InP for the switch 2010 All Silicon (15 dB/ns) Trade off between waveguide attenuation and switch ER (limit) Spires Switches Courtesy of John Bowers, University of California, Santa Barbara ORES School, Levico, 2013 A. Melloni INTEL 2010 Slow down photons Transmission c velocity group refractive index ng of the material: Atomic resonances, band edge, EIT, CPO,… ng of the circuit: Resonators, Bragg Gratings, Photonic Crystals, Brillouin and Raman,… ORES School, Levico, 2013 A. Melloni Slow down photons ORES School, Levico, 2013 A. Melloni Tunable Delay lines 1 byte continuously tuneable delay at 10 and 100 Gbit/s demonstrated OUT open rings IN λr = λin closed rings λr ≠ λin F. Morichetti et al., Optics Express, Vol. 15, 25, December 2007 A. Canciamilla et al., Journal of Optics, IOP, 2010 A. Melloni et al., IEEE Photonics Journal, vol. 1, no. 4, 2010 ORES School, Levico, 2013 A. Melloni The CROW in reflection Out Locked rings (off-resonance) in In 0.8 350 In 300 Minimum delay 0.6 0.4 0.2 Delay [ps] Intensity 1 r ≠in 200 150 100 50 0 -200 -100 250 0 100 200 Time [ps] ORES School, Levico, 2013 300 A. Melloni 400 500 0 -20 -15 -10 -5 0 5 Frequency [GHz] 10 Frequency [GHz] 15 20 The CROW in reflection Out Locked rings (off-resonance) M = 2 in In Open rings (on-resonance) 0.8 0 In 2 Delay [ps] Intensity 1 r ≠in 0.6 0.4 0.2 0 -200 -100 0 100 200 300 Time [ps] ORES School, Levico, 2013 A. Melloni 400 500 Frequency [GHz] R-CROW: a reconfigurable delay line Out M = 4 Locked rings (off-resonance) in In Open rings (on-resonance) 0.8 0 In 2 0.6 Delay [ps] Intensity 1 r ≠in 4 0.4 0.2 0 -200 -100 0 100 200 Time [ps] 300 400 500 F. Morichetti et al., Optics Express, no. 25, Dec. 2007 ORES School, Levico, 2013 A. Melloni Frequency [GHz] R-CROW continuous tuning ORES School, Levico, 2013 A. Melloni Data transmission at 10 Gbit/s 100 ps Intensity modulation OOK NRZ @ 10 Gbit/s In Reconfiguration - hitless - time 100 s - power 5 mW ORES School, Levico, 2013 Out A. Melloni Tuneable pulse delay @100Gbit/s B = 87 GHz 10 ps In τ Out Normalized intensity Fractional delay = 7.5 ps/RR 1 (0) 0.8 Storage efficiency 0.66 bit/RR 89 ps (8 bits) 0.6 9 ps (4) 0.4 (8) 0.2 Fractional loss ≈ 1.1 dB/bit (12) 11 ps 0 0 20 ORES School, Levico, 2013 40 60 Delay [ps] A. Melloni 80 100 120 Pulse Broadening (1 byte) ≈ 20% ORES School, Levico, 2013 A. Melloni High level circuit design Final User: PICs design at a circuit level using a selected set of elementary functional elements (BBs), according to well defined rules (DKs) materials Builiding Blocks technol. Design kits waveguides Generic Foundries devices circuits packaging modules Final Users ORES School, Levico, 2013 A. Melloni systems Modelling of photonic Building Blocks E jB EM analysis H jD J B H D Numerical simulations BB model S Characterization 3,53 Simulation group index 3,52 Higher order mode exp 3,51 3,5 TE TE 3,49 TM TM 3,48 3,47 fundamental mode 3,46 1 2 width [um] ORES School, Levico, 2013 3 4 A. Melloni Circuit approach (high abstraction level) • realistic model • no information on geometry & materials • access only to input/output port waves • very fast, suitable for large circuits BBs of the SAPPHIRE platform Straight & bent waveguides Waveguide crossing Ring resonators Directional couplers Grating assisted coupler (GAC) Heaters Bragg gratings ORES School, Levico, 2013 In/Out mode adapter A. Melloni BBs of the SAPPHIRE platform Straight & bent waveguides Waveguide crossing Ring resonators Grating assisted coupler (GAC) Directional couplers Heaters Bragg gratings In/Out mode adapter ORES School, Levico, 2013 A. Melloni Design kits BB , model tB K Lc tX Design rules ‐ BB connections ‐ validity range of the model ‐ layout constraints ‐ quality assessment ‐… Analytical model (S matrix) Circuit parameters & variables Mask layout ORES School, Levico, 2013 A. Melloni SAPPHIRE design manual Release 1 (July 2012) Libraries for ASPICTM simulator SAPPHIRE BBs www.aspicdesign.com Play with realistic BB 1600 BBs; 100 lambda points 1 min Phoenix Direct exportation of the mask layout ORES School, Levico, 2013 A. Melloni ORES School, Levico, 2013 www.phoenixbv.com www.aspicdesign.com CITCUIT SIMULATOR A. Melloni