1 / 51

Organic Nonlinear Optical Devices and Integrated Optics

Organic Nonlinear Optical Devices and Integrated Optics. Outline. Directional Coupler Nonlinear Fabry-Perot Interferometer Frequency Converter Optical Limiter Integrated Optics Conclusions. Signal Switching I: Directional Coupler. Directional Coupler.

lars-franks
Download Presentation

Organic Nonlinear Optical Devices and Integrated Optics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Organic Nonlinear Optical Devices and Integrated Optics

  2. Outline • Directional Coupler • Nonlinear Fabry-Perot Interferometer • Frequency Converter • Optical Limiter • Integrated Optics • Conclusions

  3. Signal Switching I:Directional Coupler

  4. Directional Coupler • Interaction length and refractive index difference of the cores control the splitting ratio

  5. Fluorine doped polyimide • Fluorine content controls the refractive index of polyimide • Core and cladding layer can be made from the same polymer---polyimide.

  6. Fabrication • To make multi-layer patterned structure, only need: spin coating, photolithography and RIE mask

  7. Nonlinear directional coupler • Refractive index changes with light intensity • Splitting ratio changes with light intensity

  8. Material requirement • Low switching power: High n2 ,(2) • Fast switching: Low response time • Low propagation loss: Low absorption • High optical damage threshold • High thermal stability

  9. A candidate: DPOP-PPV • A side chain substituted PPV • Loss = 0.4 dB/cm at 920 nm • n2 = 1.1e-14 cm2/W • Imax > 16 GW/cm2 • Tg = 163C

  10. Experimental Result Waveguide 2 • Length = 1/3 beat length (0.67 cm) • Switching at 5.5 GW/cm2 Waveguide 1

  11. Advantages and applications Advantages: • All optical switching • Bar state splitting: 90/10 • Cross state splitting: 33/67 • Polymer: Easy processing Applications: • Beam splitter, Wavelength Add-Drop Multiplexer, Cross/Bar Switch

  12. Signal Switching II:Fabry-Perot Interferometer

  13. Nonlinear Fabry-Perot Device • A wavelength selective device • Wavelength of the output signal depends on refractive index of the middle medium Signal In Signal Out Pump Mirrors: Reflectivity > 95% Nonlinear medium

  14. Operation • Nonlinear middle medium: poly-1,6-dicarbazoly 1-2,4-hexadyne (DCHC) • Signal range: 700 - 900 nm • Pump range: 637 - 645 nm • Pump light changes the index of the middle medium and changes the wavelength selection at the output.

  15. Experimental Results

  16. Performance • Pump: 2 GW/cm2 at 641 nm for 0.8 ps • Turn on time: 0.33 ps • Recovery time: 3 ps • Can switch at 333 GHz • All optical switching • Very simple structure, easy processing

  17. Frequency Conversion:Second Harmonic Generation Device A waveguide-type with periodic structure

  18. Waveguide-type periodic structure • Waveguide-type: compact, easy coupling to fibre/laser • Periodic alternations of nonlinearities in the waveguide: enable phase-matching for light at  and 2. • Conversion:

  19. Periodic structure Linear material Nonlinear material

  20. Organic crystal + Semiconductor • Nonlinear material: mNA (organic crystal grown on the grating) • Linear material: SiN (grating)

  21. 5 mm 50 nm 3 m Performance • mNA: d33 = 20 pm/V • Period = 7 m • Length = 5 mm • Wavelength = 1.06 m • Conversion efficiency = 0.16% /W/cm2 (2) = 2*d33

  22. An all-polymer one • Nonlinear polymer: diazo-dye-substituted • Linear polymer: UV curable epoxy resin

  23. Fabrication Serial grafting technique: Photolithography RIE

  24. 5 mm 2 um 6 m Experimental Results • The nonlinear polymer: d33 = 15 pm/V (after poled at 35 MV/m at 140C) • Loss = 1.2 dB/cm • Period = 32 m • Wavelength = 1550 nm • Conversion efficiency = 0.5%/W/cm2

  25. Signal Processing:Optical Limiter

  26. Operation of Optical Limiter • Low fluence: Linear transmittance • High fluence: Clamped output level

  27. Reverse saturable absorption • Low intensity: Molecule is in low absorption state. Linear transmittance • High intensity: Molecule is in photoinduced absorbing state. The material becomes highly absorptive. • Candidate material: • Metallo-Phthalocyanines • Fullerenes

  28. Metallo-Phthalocyanines • Very weak ground state absorption • Strong excited state absorption

  29. Experimental Results C60 in toluene AlClPc in methanol • Length = 1 cm • Wavelength = 532 nm • Pulse width = 8 ns InClPc in toluene

  30. Fullerenes (Bucky balls) • All-carbon cluster • Abundance of C=C gives plenty delocalizeable electrons • C60, C70, C 76, ...

  31. Experimental Results • Solvent used plays an important role

  32. Linear + Nonlinear:Integrated Optics

  33. Advantages of polymer • Low loss: 0.1 dB/cm at 1550 nm • Controllable nonlinearities by doping/poling • Low cost: only need spin-coating, photolithography and RIE • Mechanical properties: rugged, flexible • Precise control of refractive index: conveniently done by doping • Convenient thickness control: spin-coating

  34. Example 1: All polymer waveguide and MZ • All polymer 3-D structures • Achieve multi-level interconnections

  35. Material • UV15LV: low loss polymer as waveguide • Polyurethane with tricyano chromophores: Active polymer with electro-optic coefficient = r33= 12 pm/V • Waveguide loss = 0.5 dB/cm

  36. Phase modulator • Upper level: EO modulator • Lower level: waveguide

  37. Example 2: Optical Transceiver

  38. Characteristics • Integrate polymer waveguide into semiconductor system • Use polymer for waveguide and splitter • Easy fabrication of polymer Y-branch structure

  39. Example 3: Laser array and beam combiner Laser array Polymer beam combiner

  40. Material Polymer waveguide The polymers are spin-coated on the laser-array-existing semiconductor substrate

  41. Features and applications • Loss < 1 dB/cm • Good polymer adhesion to the substrate • Applications: • Wavelength multiplexer/demultiplexer • MW-O-CDMA transmitter

  42. Conclusions Polymers are good for: • waveguide structure: low loss • EO or nonlinear operation: high and controllable nonlinearities • Multi-level structure (3D): result of easy processing Hybrid semiconductor/polymer structures or all polymer structures give rise to ample opportunities

  43. Reference 1 • Polymer Directional Coupler • J. Kobayashi et al., “Directional Couplers Using Fluorinated Polyimide Waveguides,” Journal of Lightwave Technology, Vol.16, No. 4, pp. 610-613, 1998. • T. Gabler et al., “Application of the polyconjugated main chain polymer DPOP-PPV for ultrafast all-optical switching in a nonlinear directional coupler,” Journal of Chemical Physics, Vol. 245, pp. 507-516, 1999. • Polymer Fabry-Perot Device • M. Bakarezos et al., “Ultrafast nonlinear refraction in an integrated Fabry-Perot etalon containing polydiacetylene,” Proc. CLEO ‘99, CWF12, pp. 258, 1999.

  44. Reference 2 • Polymer waveguide second harmonic generation devices • T. Suhara et al., “Optical Second-Harmonic Generation by Quasi-Phase Matching in Channel Waveguide Structure Using Organic Molecular Crystal,” IEEE Photonic Technology Letters, Vol. 5, No. 8, pp. 934-936, 1993. • Y. Shuto et al., “Quasi-Phase Matched Second-Harmonic Generation in Diazo-Dye-Substitued Polymer Channel Waveguides,” IEEE Journal of Quantum Electronics, Vol. 33, No. 3 pp. 349-357, 1997. • Optical limiter • Y. Sun et al., “Organic and inorganic optical limiting materials. From fullerenes to nanoparticles,” International Reviews in Physical Chemistry, Vol. 18, No. 1, pp. 43-90, 1999. • Integrated Optics • S. M. Garner et al., “Three-Dimensional Integrated Optics Using Polymers,” IEEE Journal of Quantum Electronics, Vol. 35, No. 8 pp. 1146-1155, 1999. • N. Bouadma et al., “Monolithic Integration of a Laser Diode with a Polymer-Based Waveguide for Photonic Integrated Circuits,” 1994. • T. Ido et al., “A simple low-cost polymer PLC platform for hybrid integrated transceiver modules,” 2000

  45. Appendix A

  46. Semiconductor NLDC • Based on MQW SC laser • Operate at the transparency point

  47. Properties • Good nonlinearity • Fast response • Lower switching power • Complicated structure (e.g. MQW) • Need current injection (120 mA) • Loss = 25 dB/cm at 879 nm

  48. Other SC structures [Villenevue, 1992] • no current injection is required • still need MQW • splitting ratio and switching power are comparable to the nonlinear polymer ones. • Semiconductor Directional coupler • S. G. Lee et al., “Subpicosecond switching in a current injected GaAs/AlGaAs multiple-quantum-well nonlinear directional coupler,” Applied Physics Letters,Vol. 64, pp. 454-456, 1994. • A. Villeneuve et al., “Ultrafast all-optical switching in semiconductor nonlinear directional couplers at half the band gap,” Applied Physics Letters, Vol. 61, pp. 147-149, 1992.

  49. Appendix B

  50. Carrier generation through nonlinear optical process • Direct bandgap material: • 2PA • intensity dependent: effective for ultrashort pulse (ps to sub-ps) • Indirect bandgap material: • linear indirect absorption • fluence dependent: good for ps to 100s ns

More Related