Sensor based on Domain Inverted Electro-Optic

Transcription

1 Large Dynamic Range Electromagnetic Field Sensor based on Domain Inverted Electro-Optic Polymer Directional Coupler Alan X. Wang Ray T. Chen Omega Optics Inc., Austin, TX -1-

2 Application of Electric Field Sensors: Electromagnetic Attack Alarming Medical Apparatuses Microwave-Integrated Circuit Testing Ballistic Control Health Protection (<100KHz) --

3 Electronic Sensor v.s. vs. Photonic Sensor Drawbacks of Conventional Electronic Sensor: Disturbance from electrical cables Narrow bandwidth Bulky size Advantages of Photonic EM Sensor: Free of disturbance to EM waves Broad bandwidth Compact size Precise measurement

4 Domain Inverted E-O Polymer Directional Coupler with Super High Dynamic Range DARPA MORPH E-O Polymer Domain Inverted Y-fed Directional Coupler -4-

5 What is E-O Polymer Materials? Chromophore + - Thin film - CLD1 V Host Polymer APC or PMMA Light ~ Pockels effect: Δn = 1 n 3 γe -5-

6 Materials Comparison Materials Polymers Si/SOI III-V LiNbO 3 Optical Loss ~1 0. ~ E-O efficiency (pm/v) 450 N/A <5 30 Bandwidth (GHz) Fabrication Process Various CMOS RIE Ti diff. Integration Easy Standard Difficult No Cost Low Low Highest High Reliability Moderate High High High Improvement Potential Yes No No No -6-

7 Design of Domain Inverted E-O Polymer Directional Coupler Nonlinear Distortion in RF Photonics Signal RF Photonic link Signal + distortion E-O modulator Modulator f 1 f Third Order Intermodulation Distortion (IMD3) f 1 -f f -f 1 f 1 f RF I out = I0 I0 + cos[ φbias + Δφ( V )] Harmonic Signal -7-

8 Y-fed Directional Coupler based on Domain In erted Wa eguide Domain-Inverted Waveguide = = i i o R jb A jb A R M M R R, S: Complex amplitude i i o S A jb A jb S S H. Kogelnik and R. V. Schmidt, "Switches directional couplers with alternating ß", IEEE J. of Quantum Electron., vol. 1, pp , July = = = 1 1 ) ( n n h n V V f R Analytical Methods: Reduced simulation work Full spectrum coverage n n n dv V f d n h ) (! 1 = are the Taylor coefficients Full spectrum coverage Small errors -8-

9 Expression and amplitude of the signals from the Y-fed directional coupler Signal Frequency Amplitude (up to the 7th order expansion) DC 0 1/ Fundamental f 1, f h7a + h5a + h3a + h1a nd Harmonic f 1, f 0 IMD f 1 -f, f 1 +f rd Harmonic 3f 1, 3f h 7a + h5a + h3a IMD3 f 1 -f, f -f h 7a + h5a + h3a How to characterize the linearity of the optical modulators? V = a[sin( π f t) + sin(πf 1 t IMD3 is the most important t spurious signal because: It has the largest magnitude It is very close to the fundamental signals )] IMD3 suppression at 10% modulation depth

10 Design of Domain Inverted Modulator Schematic of the waveguide structure Simulation of the conversion length 3 μm.7 μm 3 μm UFC-170A LPD-80/APC, n=1.61, r 33 =80pm/V 0.5μm 5μm 10μm UV15-LV, n=1.49 Coupling length :lc=3.55mm at λ=1.55 μm -10-

11 Performances of YFDCs with different number of domains Name MZM Device 1 Device Device 3 Device 4 Type 1-domain 1-domain -domain 3-domain 4-domain Normalized Section Length s 1 =.8595 s 1 =.85 s = s 1 = s = s 1 =.1884 s = s 3 =.5464 s 3 = s 4 =.6648 Average IMD suppression 10%~50% MD(dB) Driving Voltage Maximum Modulation Depth 100% 7.6% 98% 96% 99.7% -145dB/Hz noise level(db/hz) noise level(db/hz) -11-

12 ¾Device Fabrication UFC170A AJCJL1/APC V UV 15 LV UV 15 ~ ~ ~ ~ ~ ~ ~ Intrinsic silicon Hot plate -1-

13 Domain Inverted E-O Poling by Pulse Voltage Working Condition E-O poling direction EM Wave direction Top S S 1 +V Gold Gold Key Points: E-O poling without top cladding Domain inverted poling -V No bottom electrode Heavily Doped Silicon -13-

14 E-O Polymer Photonic EM Wave Sensor Characterization RF 1GHz Xiaolong Wang, Beom-Suk Lee, Ray T. Chen, Large Dynamic Range Electromagnetic Field Sensor based on Domain Inverted Electro-Optic Polymer Directional Coupler, Invited Presentation, SPIE Photonics West conference, RF and Millimeter-Wave Photonics (Conference 7936), San Francisco, January -7, 7, 011

15 where ε 0 = F/m c= m/s E is the maximum amplitude of the electric field Minimum Electric Field 30V/m RF Power Density 0.3mW/cm Maximum V/m 59KW/cm Solicitation Requirement: milliwatts per square centimeter to kilowatts per square centimeter Exactly Matched!

16 IMD3 Suppression MZ Modulator Fundamental IMD3 0dB 50dB Device 0: MZM Device 1: 1DM Y-fed DC Device : DM Y-fed DC Device 3: 3DM Y-fed DC Device 4: 4DM Y-fed DC Linear Modulator db higher h average IMD3 suppression from 10%~50% modulation depth 47dB higher IMD3 0% modulation depth Boem-Suk Lee, Che-Yun Lin, Xiaolong Wang, Jingdong Luo, Alex K.Y. Jen, and Ray T. Chen, Bias-free electro-optic polymer based two-section Y-branch waveguide modulator with -db linearity enhancement, Optics Letters, Vol.34, No.1, pp (009) -16-

17 Spurious Free Dynamic Range MZ type Definition of Spurious Free Dynamic Range (SFDR) DC type Beomsuk Lee, Xiaolong Wang, Ray T. Chen, and Raluca Dinu, Electro-Optic Polymer Y-Brunch Directional Coupler Modulator with High Linearity, submitted to IEEE Photonic Technology Letters 11dB higher SFDR! -17-

18 Small Signal Modulation Measurement Laser Device EDFA RF source λ=1.55μm Modulation depth = 4% Frequency range ~6.5GHz Photo detector onse (db) Respo Microwave Spectrum -15 Analyzer -0 Frequency (GHz) 3-dB electrical bandwidth ~ 10GHz