Photonic components for signal routing in optical networks on chip

15 th International Conference on Transparent Optical Networks Cartagena, Spain, June 23-27, 213 Photonic components for signal routing in optical networks on chip Vincenzo Petruzzelli, Giovanna Calò Dipartimento di Elettronica ed Elettrotecnica, Politecnico di Bari Via Re David, 2-7125 Bari Phone (39) 8-5963645 - Fax (39) 8-596341 - e-mail: petruzzelli@mail.poliba.it

OUTLINES Progress in silicon based technology Why rapid development of the Integration of Photonics networks on chip? 1D PBG devices for wavelength division multiplexing applications on photonic networks on chip 2D PBG devices for wavelength routing in photonic networks on chip Conclusions

Why Silicon Photonic Technology? Silicon can be considered the workhorse of the semiconductor industry Due to its abundance and versatility the silicon can be regarded as a dominant platform for the microelectronic fabrication Crystalline silicon photonic waveguides are capable of transporting wavelength-parallel optical data with terabit per second data rates across the entire chip Silicon waveguides can be bent, crossed and coupled, creating regions where the optical signal can be passed from one waveguide to another one

Why Optical Interconnects? The recent (i.e. since 26) advances in: Massive fabrication of silicon photonic devices Integration of silicon photonic devices in CMOS electronic circuits photonic technology practical for a new generation of NoCs. Advantages of photonic NoCs: High transmission bandwidth Low power consumption Low latency

Integration of Photonic Networks on chip - NoC DRAM CMP stack SUPERCOMPUTING BOARD Photonic Network Memory CMP Chip MultiProcessor [1] A. Biberman, K. Bergman, Rep. Prog. Phys. 75 (212) 4642

Photonic Building Blocks Photonic NoC High speed Modulators Photodetectors 1 4 Gb/s [1] Q. Xu et Al., Optics Express, Vol. 15, Issue 2, pp. 43-436 (27) [2] L. Chen, Michal Lipson, Optics Express, Vol. 17, Issue 1, pp. 791-796 (29) SWITCH MATRIX for the signal routing all over the network Basic elements: Switches, filters, etc.

SOI WAVEGUIDES 2.8 y SiO 2 w Si d Effective refractive index 2.6 2.4 2.2 2 1.8 1.6 d=2 nm w 1 w 2 x 1.4.1.2.3.4.5.6 Width w [µm] Periodic effective refractive index by varying the waveguide width w 1D PBG WAVEGUIDE

1D PBG WAVEGUIDE w 1 SiO 2 d w2 l 1 l 2 Si Bragg Wavelength ( n 1l1 n 2l2 ) λ = 2 + B eff eff PBG: λ 3 nm Bragg wavelength 1.55 µm Si core refractive index 3.477 SiO 2 substrate and cladding refractive index 1.444 Waveguide depth d 2 nm Width of the first layer w 1 5 nm Width of the second layer w 2 26 nm Length of the first layer l 1 18 nm Length of the second layer l 2.18 µm Number of layers N 32 Transmittance, Reflectance 1.9.8.7.6.5.4.3.2.1 T R 1.3 1.4 1.5 1.6 1.7 1.8 wavelength λ [µm]

1D PBG WAVEGUIDE with 1 DEFECT L d z Transmittance, Reflectance 1.9.8.7.6.5.4.3.2.1 R 1.3 1.4 1.5 1.6 1.7 1.8 Wavelenght λ [um] T Transmittance, Reflectance 1.9.8.7.6.5.4.3.2 R T.1 1.3 1.4 1.5 1.6 1.7 1.8 Wavelenght λ [um] L d =2l 2 =.36 µm 1 channel L d =1 µm 6 channels

4 number of channels 35 3 25 2 15 1 5 1D PBG WAVEGUIDE with 1 DEFECT Defect length variation 1 2 3 4 5 defect length [µm] Channel bandwidth [nm] 2 18 16 14 12 1 8 6 4 FSR [nm] 16 14 12 1 8 6 4 2 2 1 2 3 4 5 defect length [µm] 1 2 3 4 5 defect length [µm]

1D PBG WAVEGUIDE with 2 DEFECTS Defects Def 1 Def 2 1 M-m M=N/2 M+m N N t1 Nt2 N t1 Transmittance T 1.9.8.7.6.5.4.3.2.1 m=2 m=4 m=8 1.3 1.4 1.5 1.6 1.7 1.8 Wavelength λ [µm] Wavelength λ [µm] 1.7 1.65 1.6 1.55 1.5 1.45 1.4 2 4 6 8 1 12 14 Defect position index m

BINOMIAL DISTRIBUTION of DEFECTS 16 16 (a) 8 16 8 (b) 4 12 12 4 (c) 2 8 12 8 2 (d) Transmittance T 1.9.8.7.6.5.4.3.2.1 2 defecst 1 defect 2 BINOMIAL DEFECTS L d =2l 2 =.36 µm 1 channel Channel bandwidth [nm] 1 defect 41.5 2 binomial defects 11.5 1.3 1.4 1.5 1.6 1.7 1.8 Wavelength l [um]

BINOMIAL DISTRIBUTION of 2 DEFECTS L d =1 µm 6 channels 1 Transmittance T.9.8.7.6.5.4.3.2.1 1.3 1.4 1.5 1.6 1.7 1.8 Wavelength λ [µm] 2 defects 1 defect Transmittance T.9.8.7.6.5.4.3.2.1 2 defects 1 defect 1.55 1.56 1.57 1.58 1.59 1.6 1.61 Wavelength l [um] FSR [nm] Channel bandwidth [nm] 1 defect 43.9 7.4 2 binomial defects 44.2 12.6

λ-routers for Photonic NoC Principle scheme Physical scheme Bend Waveguide Crossing Photonic Crystals for the Optical Interconnects Resonator We need: waveguides resonators bends crossings

NoC Components in Photonic Crystals Straight waveguide FDTD Simulations Bend waveguide Silicon Pillars

NoC Components in Photonic Crystals West OUT North IN South Broadband Crossing λ=1.35 µm -1.6 µm FDTD Simulations Input at South port East transmittance.9.8.7.6.5.4.3.2.1 W and E are isolated 1 Output at North port 1.3 1.35 1.4 1.45 1.5 1.55 1.6 wavelength [µm] Maximum attenuation A=-.75 db atλ=1.571 µm W E N 1.571

NoC Components in Photonic Crystals North λ 1 1x2 Photonic Crystal Ring Resonator Switch OFF resonance λ 1 Input South Output North West IN South ON resonance λ 2 Input South Output East λ 2 East transmittance 1.9.8.7.6.5.4.3.2.1 λ 1 1.3 1.35 1.4 1.45 1.5 1.55 1.6 wavelength [µm] λ 2 E N

In North NoC Components in Photonic Crystals 4x4 Photonic Crystal Ring Resonator Switch Matrix OUTPUT Out North INPUT In East Out West In West Out East transmittance 1.9.8.7.6.5.4 W E S.3 Out South In South.2.1 1.48 1.49 1.5 1.51 1.52 1.53 1.54 1.55 wavelength [um]

Conclusions Silicon components make possible the optical interconnects on chip. Photonic crystals on silicon integrated on NoC: to perform all the operations of the conventional silicon components, but with more compact sizes. 1D PBG multi-wavelength filters: the Newton binomial distribution of defects allow flat transmission channels with larger bandwidth. 2D PhCs for the wavelength routing in photonic networkds on chip