Two dimensional photonic crystal waveguides in high index materials enable integrated optical devices with an extremely small geometrical footprint on the scale of micrometers. Slotted waveguides are based on the guiding of light in low refractive index materials and a field enhancement in this particular region of the device. In this letter we experimentally demonstrate electro-optic modulation in slotted photonic crystal waveguides based on silicon-on-insulator substrates covered and infiltrated with nonlinear optical polymers. A photonic crystal heterostructure is used to create a cavity, while simultaneously serving as an electrical connection from the slot to the metal electrodes that carry the modulation signal. © 2009 American Institute of Physics. ͓DOI: 10.1063/1.3156033͔Electrically driven optical modulation in silicon photonics typically relies on interactions between the optical mode and a free carrier plasma via either carrier depletion, injection, or accumulation. 1-3 The achievable modulation speed using these methods is limited by the time constants related to the injection or removal of carriers from the optical waveguide. In contrast, modulation via nonlinear optical ͑NLO͒ polymers accesses the electronic polarization of the organic molecules, which allows extremely high modulation speeds extending up to frequencies in the terahertz range. 4 Furthermore, molecular engineering of organic molecules has led to extremely high Pockels-coefficients in polymers exceeding 300 pm/V, 5 which is ten times the value available in lithiumniobate, the standard inorganic material used in electro-optic ͑EO͒ applications. Photonic devices based on a hybrid material system merging silicon and polymer are therefore attractive since they combine the strong light confining abilities of silicon with the superior NLO properties of polymers.All-optical and EO-modulation in such hybrid silicon and NLO-polymer systems has been demonstrated for slotted photonic wire based Mach-Zehnder and ring-resonator modulators. 6-8 Concepts based on slotted photonic crystal ͑PhC͒ waveguides can exploit slow light mechanisms or high quality factor cavities to achieve very compact device dimensions and have been discussed recently. 9-11 We propose a concept using a double heterostructure cavity 11-13 in a slotted silicon PhC waveguide, infiltrated with NLO-polymer to operate as an EO-modulator. Figure 1 shows a scanning electron micrograph of the structure. The 150 nm wide slot in the center of the waveguide is filled with NLO-polymer ͑n poly = 1.63͒ and the strong overlap between the optical field and the polymer makes the effective index of the propagating mode very sensitive to any refractive index changes in EOpolymer. The PhC features a background doping density of 10 15 cm −1 and therefore serves as an electrical conductor from the metallic contact pads to the slot, while keeping the optical field away from the metal regions and hence preventing additional losses. The double heterostructure design of the PhC ͑a = 410 nm, r / a = 0....

In this Letter we demonstrate broadband electro-optic modulation with frequencies of up to 40 GHz in slotted photonic crystal waveguides based on silicon-on-insulator substrates covered and infiltrated with a nonlinear optical polymer. Two-dimensional photonic crystal waveguides in silicon enable integrated optical devices with an extremely small geometric footprint on the scale of micrometers. The slotted waveguide design optimizes the overlap of the optical and electric fields in the second-order nonlinear optical medium and, hence, the interaction of the optical and electric waves.

Abstract:We present a novel concept of a compact, ultra fast electro-optic modulator, based on photonic crystal resonator structures that can be realized in two dimensional photonic crystal slabs of silicon as core material employing a nonlinear optical polymer as infiltration and cladding material. The novel concept is to combine a photonic crystal heterostructure cavity with a slotted defect waveguide. The photonic crystal lattice can be used as a distributed electrode for the application of a modulation signal. An electrical contact is hence provided while the optical wave is kept isolated from the lossy metal electrodes. Thereby, well known disadvantages of segmented electrode designs such as excessive scattering are avoided. The optical field enhancement in the slotted region increases the nonlinear interaction with an external electric field resulting in an envisaged switching voltage of approximately 1 V at modulation speeds up to 100 GHz. real-time second-harmonic generation study of a novel covalently functionalized amorphous nonlinear optical polymer," J. Appl. Phys. 66, 2559-2567 (1989). 2008 Optical Society of America

In this letter, we report on the experimental observation of a complete in-plane photonic band gap for transverse-electric-like polarized modes in a polymer photonic crystal slab with a triangular array of holes. We performed transmission measurements on two-dimensional photonic crystal slabs in both principal directions of the triangular lattice. For a propagation distance of 40 lattice constants, the transmission was effectively suppressed regardless of propagation direction below −15 dB over a bandwidth of 65 nm. The experimental results are in excellent agreement with theoretical predictions obtained from band diagram calculations and finite integration time domain techniques.

We report on the fabrication and characterization of photonic crystal slab waveguide resonators which contain a nanostructured second‐order nonlinear optical polymer. The combination of a photonic crystal resonator realized in a second‐order nonlinear optical polymer allowed the detection of electro‐optical modulation of light with a sub‐1‐V sensitivity. Furthermore we report on the synthesis of novel nonlinear optical polymers with large second‐order hyperpolarizability and improved glass transition temperature. The polymer slab waveguide is micro patterned by means of electron‐beam lithography and reactive ion etching. The photonic crystal slab‐based resonator consisted of a square lattice of holes carrying a linear defect. Applying an external electric modulation voltage to electrodes leads to a linear electro‐optical shift of the resonance spectrum and thus to a modulation of the transmission at a fixed wavelength based on the electronic displacement polarization in a noncentrosymmetric medium (Pockels effect). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)