nanophotonic Integrated Circuit (npic( npic) Anis Rahman, Ph.D. Applied Research & Photonics, Inc. 470 Friendship Road, Suite 10, Harrisburg, PA 17111 http://arphotonics.net arphotonics.net/ 7th International Conference Numerical Simulation of Optoelectronic Devices 24 27 27 Sept. 2007 University of Delaware, Newark, DE 19716 (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 1
Plan Introduction/Company Dendrimer Terahertz generation/electro-optic optic Route Modeling, Simulation, Data Other photonic components Concluding Remarks (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 2
NanoPhotonics An opportunity to create smart devices by combining nanotechnology and photonics 1880 Bell: Photophonic transmitter 1905 Einstein: measured sugar molecule size ~ 1 nm 1985 Tomalia: Dendrimer a a polymeric nanomaterial allows to combine the power of nanotechnology and photonics can result in a number of important applications (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 3
Dendrimer A polymeric nanomaterial 3-D, core-shell molecule Generation: G0-G11 G11 Size: 4-12nm4 Multiple functionality: terahertz waveguide, modulator, amplifier, and band gap Established route for transition to production Cost-effective Multifunctional dendrimer molecule (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 4
Multivalent dendrimer No. of end groups: 2 (G+2), G = 0 to 11 G3 3 PAMAM dendrimer: 2 5 = 32 groups each molecule can accept up to 64 dopant molecules Potentially 64 fold increase of χ (2) for G3 Higher for higher generation High field poling required There are many chromophore to choose from χ (2) = nfβ cos 3 θ (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 5
Optical properties Variation of refractive index of cured dendrimer film compositions by natural index contrast (NIC) method Refractive Index 1.64 1.62 1.6 1.58 1.56 1.54 1.52 1.5 1.48 1.46 1.44 2.5 800 900 1000 1100 1200 1300 1400 1500 1600 Wavelength (nm) Dendrimer A Dendrimer B Dendrimer B Glass_Sellmeier Thickness Dendrimer film s s RI can be controlled by its generation, doping, and process parameters 3.5 3.4 3.3 3.2 3.1 3.0 2.9 2.8 2.7 2.6 Thickness (µm) FTIR spectra of dendrimer film exhibits high transmission over the NIR region. (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 6
Terahertz waveguide EO rectification waveguide Photoconductor Reactor/Accelerator E χ E (2) 2 THz, max pump Principle of THz generation in a waveguide Terahertz power is proportional to the electro-optic coefficient and to the square of input pump power. EO rectification in waveguide is scalable, not limited by heat dissipation or emission saturation: w THz = f ( wp, r33, I eff, A) w p : pump power, r 33 : EO coefficient I eff : effective intensity, A: # of waveguide in array THz power scaling as a function of pump power in GaP: approx. quadratic. Ref. Chang, et al., OP. EX., 14, 7909, (2006) (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 7
EO Properties: poling (a) (b) Sketch of dipole orientation in (a) unpoled and (b) corona poled dendrimer film. Poling Current (µa) 10 9 8 7 6 5 4 3 2 1 0 (a) 6100 6200 6300 6400 6500 6600 6700 6800 Poling Voltage (V) Poling current (µa) 10 9 8 7 6 5 4 3 2 1 0 1600 2000 2400 2800 3200 Time (s) (a) Poling I-V, I and (b) decay of poling current in dendrimer film. (b) (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 8
EO measurements 1.5 Modulated signal Vac (V) 1.3 1.1 0.9 0.7 0.5 0.3 0.1-0.1 y = 0.0704x 0 5 10 15 20 Applied voltage Vpp (V) Poled dendrimer film exhibit excellent linear relationship between en modulated-beam signal, Vac and applied voltage Vpp (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 9
Refractive Index & EOC 1.5600 Pockels effect 170 1.5400 150 n 1.5200 1.5000 1.4800 1.4600 Unpoled Poled Glass r 33 (pm/v) 130 110 90 1.4400 70 1.4200 600 800 1000 1200 1400 1600 λ (nm) Refractive index difference between poled and unpoled dendrimer (Metricon 2010). Dendrimer is suitable for terahertz generation 50 30 600 800 1000 1200 1400 1600 λ (nm) 3 n Δn = r33e 2 r 33 ~130 pm/v @ 633nm (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 10
High power terahertz generation 10000 dendrimer_arp Ref. 1 1000 Simulation w THz max (µw) 100 10 1 0.1 Dendrimer GaP 0.01 0 1 2 3 4 5 6 7 8 9 10 11 12 13 w p (W) Red circles: data from Chang, et al., OPTICS EXPRESS, 14, 7909, (2006) Yellow circles: Dendrimer: ~100 times higher power (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 11
Simulation of terahertz power from dendrimer waveguide array Applied Research & Photonics, Inc. 2007 (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 12
Terahertz Spectrum Simulation Typical terahertz pulse and spectrum (simulation): (a) A typical terahertz pulse, (b) normalized terahertz spectrum of the pulse shown in (a). (c) and (e): pulses with width 100 fs and 690 fs, respect., at 80 MHz. (d) and (f): terahertz spectra for (c) & (e). Amplitude (arb.) 1.2 1.0 0.7 0.5 0.2-0.1-0.3-0.6-0.8-1.1 (a) 0.0 0.5 1.0 1.5 2.0 2.5 pico seconds (c) (e) db Norm 0-5 -10-15 -20-25 -30-35 -40-45 Fourier Spectrum (b) -50-50 0 2 4 6 8 10 Frequency (THz) (d) (f) 0-5 -10-15 -20-25 -30-35 -40-45 (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 13
Design & Simulation Waveguide: Core Technology Top Layer Core Layer First Layer Si wafer Dendrimer based waveguide design and simulation. From left: half-core, field intensity, design (top right) and field intensity in an array of waveguide. Functionality is determined by the core layer (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 14
Photonic components 2007, Applied Research & Photonics, Inc. Demonstration of photonic components from dendrimer Fabricated at Penn State University Nanofab Facility (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 15
Waveguide Array Left: Photomicrograph of an array of waveguide from dendrimer. Right: SEM micrograph showing the ridges that forms the core of waveguide. (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 16
Optical amplifier 25 20 40k 30k 20k 10k 5k 0.5k Gain (db) 15 10 Close-up of fabricated amplifier section 5 0 0 250 500 750 1000 Pump Power (mw) Simulation of erbium doped dendrimer waveguide amplification (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 17
Arrayed Waveguide Grating 0-5 Spectral response of a 48 channel AWG (simulation) Applied Research and Photonics, Inc. -10 Insertion Loss (db) -15-20 -25-30 -35-40 1539 1541 1543 1545 1547 1549 1551 1553 155 Wavelength (nm) A 48 channel TAWG and its spectral response designed from dendrimer (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 18
RAWG 2007, Applied Research & Photonics, Inc. A 16 channel RAWG and its spectral response. (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 19
Modulator Here the waveguide core is made from EO dendrimer Electrodes are added to drive the modulator Basic element for sensing (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 20
npic Input 2007, Applied Research & Photonics, Inc. Depending on the configuration Optical communication node Multi-channel sensor network (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 21
Summary Dendrimer is a workhorse matl.. for photonics. Electro-optic optic rectification is not limited by THz emission saturation or by heat dissipation power scalability. > 100 mw per chip can be generated from EO dendrimer waveguide array. Applications in molecular spectroscopy, diagnosis, security, screening, Active and passive photonic components can be integrated via monolithic fabrication Opportunities for collaboration. (C) 2007 Applied Research & Photonics - Proprietary - Anis Rahman - NUSOD 07 22