Research ArticlePHOTONICS

Organic printed photonics: From microring lasers to integrated circuits

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Science Advances  18 Sep 2015:
Vol. 1, no. 8, e1500257
DOI: 10.1126/sciadv.1500257
  • Fig. 1 Design and fabrication of a wafer-scale organic printed photonic chip.

    (A) Schematic of the fabrication of a photonic circuit by confining photon flows in printed structures. A thin film was spin-coated from a polymer solution and locally dissolved by printing solvent droplets, resulting in various microscale structures for light transport. (B) Image of a free-standing photonic chip peeled off from the substrate, indicating the flexibility and transparency of the printed photonic chip. A yellow-dye compound was doped into the chip film. (C) Image of large-scale ordered optical structures on a 1-inch wafer. (D) Microscope image showing printed microring chains of uniform size and well-defined pattern. (E) AFM image of a typical self-assembled polymer structure after printing showing the smoothness and height of the structure over the surrounding film.

  • Fig. 2 Characterization of printed microrings as high-Q resonators.

    (A) Microscopy image of the structure built for optical measurement. (Top) The optical fiber taper was coupled with a microring at the edge of the film, which was connected to a wavelength-tunable laser at one end and to a photodetector at the other end. (Bottom) The microring was uniformly illuminated when the input wavelength was found at any of its resonance modes. Scale bar, 50 μm. (B) Microscopy image of two conjugated microrings coupled with the fiber taper (top left). The incident laser was tuned to the wavelength of the resonance mode of ring 1 and/or ring 2 to illuminate the rings simultaneously (top right) or separately (bottom). Scale bar, 50 μm. (C) Frequency detuning profile of the 632.15-nm (~4.75 × 105 GHz) resonance mode from the microring resonator with a TE polarized laser. The corresponding Q factor is 4.33 × 105, as calculated from the frequency of incident light divided by the linewidth of the Lorentz fit (red). (D) Broad-range transmission spectrum from the microring, where periodic sharp dips indicate an average Q factor higher than 105.

  • Fig. 3 Low-threshold lasing from dye-doped printed microrings.

    (A) Photoluminescence (PL) microscopy image of a dye-doped microring that was locally excited by a focused 400-nm pulsed laser (~200 fs, 1 kHz). EX, excitation position. Scale bar, 20 μm. (B) Spatial polarization profile of light emission from the ring resonator. Collected areas are marked with colored arrows in (A). Polarized PL spectra (red and blue) were ascribed to the outcoupling of TE modes from the ring resonator, whereas the PL spectrum at the EX was unpolarized (black) because of the uncoupled scattering background. (C) Output spectra from the entire ring with excitation powers of 30 to 50 nJ/pulse showing the emergence of lasing modes from stimulated emission. (D) Spatial spectra of fluorescence scattering at the EX (black) and lasing guided away from the EX (red) showing amplified light emission from resonance modes in the microring. (E) Plots of PL peak intensity versus excitation showing the lasing threshold at ~40 nJ/pulse and the nonlinear energy shift at ~80 nJ/pulse. (Insets) Microscopy images of a light-emitting microring below and above the threshold.

  • Fig. 4 Organic PICs based on printed microstructures.

    (A) Microscopy image of a printed microring resonator coupled with a tangentially connected 1D waveguide (top) with two laser-burned termini (marked with red rectangles) for light outcoupling. (Bottom) The resonance modes generated by exciting the microring were collected by the waveguide and guided to the termini. (B) Corresponding spectrum from the laser-burned slot showing the guided ring resonance modes from the directional output in the coupled optical waveguide. (C) Schematic of an as-printed add-drop filter based on the coupling between 1D waveguides and microring resonators. When mixed light signals (white arrow) are inputted from the upper waveguide, the wavelength at resonance (red arrows) is guided into module I, whereas another wavelength goes into module II (blue arrows) on its distinct resonance modes. The signals can thus be distributed into designated ports, and the residual light would pass through the top bus (green arrow). See fig. S12 for details. (D) Microscopy image of coupled resonators obtained by printing two conjugated microrings at a distance of ~500 nm (top). (Bottom) The left ring was partially excited, and the right ring was illuminated through resonator coupling. The output spectrum was collected from the point of joining, indicated with a red square. (E) Corresponding spectrum shows enhancement of modulated resonance modes from the Vernier effect in coupled cavities. (F) Schematic of printed CROWs for optical memory based on programmable printed microring chains. The CROW structure produces a newly generated optical eigenmode (yellow) that can confine photons inside by coupling the resonance modes in each ring. This eigenmode brings isolated states to memorize light signals, similar to energy levels in atom clusters. More eigenmodes at different wavelengths can be obtained from the coupling between vertical ring chains and horizontal ring chains, which are shown in detail in fig. S13.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/1/8/e1500257/DC1

    Preparation and characterization of printed optical structures

    Fig. S1. Schematic of the fabrication of photonic microring patterns by jet printing.

    Fig. S2. Optical microscopy images of microring patterns prepared using various polymers on different substrates.

    Fig. S3. Microscopy images of microwires printed by continuous solvent jetting.

    Fig. S4. AFM image and roughness profile of the surface of printed microring structures.

    Size control of printed structures

    Fig. S5. Optical microscopy images of microring structures printed on polymer films of different thicknesses.

    Fig. S6. Optical microscopy images of microring structures printed by jetting different volumes of DMF solvent.

    Fig. S7. AFM images of printed microrings.

    Table S1. Structural parameters of microrings prepared under different conditions.

    Performance evaluations of printed optical waveguides and microrings

    Fig. S8. Characterization of low optical loss in printed optical waveguides.

    Fig. S9. Numerical simulation of the optical waveguiding of TE and TM modes in printed structures.

    Fig. S10. Light confinement of TM modes in a microring resonator.

    Fig. S11. Theoretical and experimental Q factor versus ring radius in microring resonators.

    Lasing behavior of dye-doped microring resonators

    Fig. S12. Lasing spectra of microring resonators of different sizes.

    Fig. S13. Power-dependent modulation of a lasing spectral shift in dye-doped ring resonators.

    Fig. S14. Modulation of a microring laser with the external stimuli of acetone vapor.

    Fig. S15. Fabrication of microring laser arrays with a broad spectral range by doping different gain media in jetting solutions.

    Light signal processing and optical memory in the printed photonic structures

    Fig. S16. Light add-drop filter assembled from designed waveguides and microring structures on a printed photonic chip.

    Fig. S17. Printed CROWs with two coupled microring chains for eigenmode optical memory.

    References (4050)

  • Supplementary Materials

    This PDF file includes:

    • Preparation and characterization of printed optical structures
    • Fig. S1. Schematic of the fabrication of photonic microring patterns by jet printing.
    • Fig. S2. Optical microscopy images of microring patterns prepared using various polymers on different substrates.
    • Fig. S3. Microscopy images of microwires printed by continuous solvent jetting.
    • Fig. S4. AFM image and roughness profile of the surface of printed microring structures.
    • Size control of printed structures
    • Fig. S5. Optical microscopy images of microring structures printed on polymer films of different thicknesses.
    • Fig. S6. Optical microscopy images of microring structures printed by jetting different volumes of DMF solvent.
    • Fig. S7. AFM images of printed microrings.
    • Table S1. Structural parameters of microrings prepared under different conditions.
    • Performance evaluations of printed optical waveguides and microrings
    • Fig. S8. Characterization of low optical loss in printed optical waveguides.
    • Fig. S9. Numerical simulation of the optical waveguiding of TE and TM modes in printed structures.
    • Fig. S10. Light confinement of TM modes in a microring resonator.
    • Fig. S11. Theoretical and experimental Q factor versus ring radius in microring resonators.
    • Lasing behavior of dye-doped microring resonators
    • Fig. S12. Lasing spectra of microring resonators of different sizes.
    • Fig. S13. Power-dependent modulation of a lasing spectral shift in dye-doped ring resonators.
    • Fig. S14. Modulation of a microring laser with the external stimuli of acetone vapor.
    • Fig. S15. Fabrication of microring laser arrays with a broad spectral range by doping different gain media in jetting solutions.
    • Light signal processing and optical memory in the printed photonic structures
    • Fig. S16. Light add-drop filter assembled from designed waveguides and microring structures on a printed photonic chip.
    • Fig. S17. Printed CROWs with two coupled microring chains for eigenmode optical memory.
    • References (40–50)

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