42.7 Gbit/s electro-optic modulator in silicon technology

Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
Optics Express (Impact Factor: 3.49). 06/2011; 19(12):11841-51. DOI: 10.1364/OE.19.011841
Source: PubMed


CMOS-compatible optical modulators are key components for future silicon-based photonic transceivers. However, achieving low modulation voltage and high speed operation still remains a challenge. As a possible solution, the silicon-organic hybrid (SOH) platform has been proposed. In the SOH approach the optical signal is guided by a silicon waveguide while the electro-optic effect is provided by an organic cladding with a high χ(2)-nonlinearity. In these modulators the optical nonlinear region needs to be connected to the modulating electrical source. This requires electrodes, which are both optically transparent and electrically highly conductive. To this end we introduce a highly conductive electron accumulation layer which is induced by an external DC "gate" voltage. As opposed to doping, the electron mobility is not impaired by impurity scattering. This way we demonstrate for the first time data encoding with an SOH electro-optic modulator. Using a first-generation device at a data-rate of 42.7 Gbit/s, widely open eye diagrams were recorded. The measured frequency response suggests that significantly larger data rates are feasible.

Download full-text


Available from: Juerg Leuthold, Apr 15, 2014
27 Reads
  • Source
    • "The optical output of the modulator is directly connected to the optical spectrum analyzer (OSA), and the transmission spectrum is measured. Sidebands together with the main peak are observed in the transmission spectrum, and their powers are used to calculate the phase modulation index [7]. The obtained modulation index (η) as a function of frequency is plotted in Fig. 2 (b). "
    Frontiers in Optics 2014, Tucson, Arizona, USA; 10/2014
  • Source
    • "The silicon in the SOH slot PCW modulator can also be doped to achieve high speed operation [30], [31]. For example, modulation speeds up to 40 GHz or over 40 Gbit/s have been demonstrated in [32], [33]. Furthermore, the antenna can be designed for broadband resonant electric field enhancement (FE) [34], [35], which is equivalent to increasing the input driving voltage of the modulator, thereby increasing the sensitivity of the sensor. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We present the design, fabrication and characterization of a compact and highly sensitive integrated photonic electromagnetic field sensor based on a silicon-organic hybrid modulator driven by a bowtie antenna. Slow-light effects in the electro-optic (EO) polymer refilled silicon slot photonic crystal waveguide (PCW), together with broadband electric field enhancement provided by the bowtie antenna, are utilized to enhance the interaction of microwaves and optical waves, enabling an ultra large effective in-device EO coefficient over 1000 pm/V and thus a high sensitivity. The EO polymer refilled slot PCW is designed for low-dispersion slow-light propagation, high poling efficiency, and high optical mode confinement inside the slot. The bowtie antenna acts not only as a receiving antenna, but also as poling electrodes during the fabrication process. A bowtie antenna integrated on doped silicon slot PCW is demonstrated to have a broad operational bandwidth, with a maximum resonance at the frequency of 10 GHz. The strongly enhanced broadband electric field is used to directly modulate the phase of the optical waves propagating through the slot PCW embedded inside the feed gap of the bowtie antenna. The phase modulation is then converted to intensity modulation using an external reference arm to form a Mach-Zehnder interferometer in our experimental setup. The sensing of electromagnetic field at 8.4 GHz is experimentally demonstrated, with a minimum detectable electromagnetic power density of $8.4, {rm mW!/!m}^{2}$ , corresponding to a minimum detectable electric field of 2.5 V/m.
    Journal of Lightwave Technology 10/2014; 32(20):3774-3784. DOI:10.1109/JLT.2014.2319152 · 2.97 Impact Factor
  • Source
    • "The discontinuity of the normal component of the displacement vector can be used to affect guiding of the majority of the electrical field energy in a narrow low index gap when the field is polarized parallel to the silicon surface, that is, perpendicular to the silicon confining walls [4], [5]. By infiltrating nonlinear material into such a gap, one can simultaneously confine electric and optical fields achieving high efficiency modulation [6], [7] sufficient for use in IQ modulation [8] that is becoming ubiquitous on long haul optical communication. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Spectral transmission measurements of grating coupled ridge waveguides transitioned to nanometric slots are found to agree with simulations when the measurements are deembedded and the ridge to gap transitions are endowed with excess propagation loss.
    2014 IEEE Photonics Conference (IPC), San Diego, CA, USA; 10/2014
Show more