Parallel-coupled dual racetrack silicon micro-resonators for quadrature amplitude modulation

Department of Electrical and Computer Engineering, Rutgers University, Piscataway, NJ 08854, USA.
Optics Express (Impact Factor: 3.49). 08/2011; 19(16):14892-902. DOI: 10.1364/OE.19.014892
Source: PubMed


A parallel-coupled dual racetrack silicon micro-resonator structure is proposed and analyzed for M-ary quadrature amplitude modulation. The over-coupled, critically coupled, and under-coupled scenarios are systematically studied. Simulations indicate that only the over-coupled structures can generate arbitrary M-ary quadrature signals. Analytic study shows that the large dynamic range of amplitude and phase of a modulated over-coupled structure stems from the strong cross-coupling between two resonators, which can be understood through a delicate balance between the direct sum and the "interaction" terms. Potential asymmetries in the coupling constants and quality factors of the resonators are systematically studied. Compensations for these asymmetries by phase adjustment are shown feasible.

Download full-text


Available from: Ryan A Integlia, Aug 24, 2014
  • Source
    • "In section VI, we have carried out tunability study of off-axis MRR and found that off-axis ring can pave the way for more compact modulator in comparison to the SOI modulator based on the conventional MRR [16], [17]. This might be suitable for high density on-chip photonic applications as it has high Q-factor with resonant notches which are very sensitive to the effective refractive index and radius of the off-axis inner ring. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we have developed a theory of an off-axis microring resonator (MRR) with single and multiple off-axis rings. The off-axis inner ring introduces tunable extra notches with many striking features in the transmission spectrum which facilitates its use as efficient modulators and sensors. A few such notches when closely packed have been used to design a compact band rejection filter with improved bandwidth (>10 nm). Moreover, these closely packed extra notches achieved by serially coupled MRRs with off-axis inner rings are tunable to reject arbitrarily chosen WDM channels. Through numerical simulations, based on both transfer matrix method and finite difference time domain method, it has been examined that off-axis MRRs cater superior performances in comparison to the serially coupled conventional MRR with respect to the device size, faster response, and low dispersion. The proposed off-axis MRRs may be used for cluster to cluster interconnects and can have other potential on-chip photonic applications in network layer. Necessary design parameters are computed from the coupled mode theory.
    Journal of Lightwave Technology 12/2013; · 2.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Parallel-coupled dual racetrack micro-resonator structures have potential applications for quadrature amplitude modulation. Fabrication of parallel-coupled dual racetrack silicon micro-resonators was conducted, while overcoming for some barriers to fabrication. Fabrication process limitations and design considerations are discussed. Fabrication results are presented. Some barriers to fabrication include stitching and overdosing in electron beam lithography. A multi-input and output test bed with optical and electrical control was necessary for device characterization. The characterization of the fabricated devices is presented, along with the related procedures. Some of the tests performed are wavelength scans and top surface scans.
    Proceedings of SPIE - The International Society for Optical Engineering 02/2012; 8266:13-. DOI:10.1117/12.908601 · 0.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Advanced optical modulation formats are a key technology to increase the capacity of optical communication networks. Mach-Zehnder modulators are typically used to generate various modulation formats. Here, we report the first experimental demonstration of quadrature phase-shift keying (QPSK) modulation using compact microring modulators. Generation of 20 Gb/s QPSK signals is demonstrated with 30 μm radius silicon ring modulators with drive voltages of ~6 V. These compact QPSK modulators may be used in miniature optical transponders for high-capacity optical data links.
    Optics Letters 04/2012; 37(7):1178-80. DOI:10.1364/OL.37.001178 · 3.29 Impact Factor
Show more