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Tetsuya Mizumoto - One of the best experts on this subject based on the ideXlab platform.

  • Silicon Waveguide Optical Isolator with Directly Bonded Magneto-Optical Garnet
    'MDPI AG', 2019
    Co-Authors: Yuya Shoji, Tetsuya Mizumoto
    Abstract:

    Silicon waveguide Optical Isolators were fabricated by direct bonding of magneto-Optical (MO) garnet. The technique allowed efficient MO phase shift owing to the use of single-crystalline garnet and negligibly thin interlayer on the silicon core layer. A Mach⁻Zehnder interferometer (MZI) provided Optical isolation utilizing the MO phase shift. High isolation, wide bandwidth, and temperature-insensitive operations had been demonstrated by tailoring the MZI design. Also, transverse electric (TE)⁻transverse magnetic (TM) mode converters were integrated to control operating polarization. In this paper, we reviewed these progresses on silicon waveguide Optical Isolators

  • Integrated Optical Isolator and Circulator in Silicon Photonics
    2018 European Conference on Optical Communication (ECOC), 2018
    Co-Authors: Paolo Pintus, Yuya Shoji, Tetsuya Mizumoto, Duanni Huang, Paul A. Morton, John E. Bowers
    Abstract:

    We present recent progress in Optical Isolators and circulators fabricated though bonding magneto-optic garnet on an SOI wafer. The nonreciprocal behavior is induced through an integrated electromagnet. Large isolation, wide isolation bandwidth and tunability are demonstrated with lower power consumption.

  • microring based Optical isolator and circulator with integrated electromagnet for silicon photonics
    Journal of Lightwave Technology, 2017
    Co-Authors: Paolo Pintus, Yuya Shoji, Tetsuya Mizumoto, Duanni Huang, Chong Zhang, John E. Bowers
    Abstract:

    In this study, we present Optical Isolators and circulators fabricated by bonding cerium-substituted yttrium iron garnet (Ce:YIG) on silicon microring resonators. A novel integrated electromagnet is fabricated by depositing a metal micro-strip on the bonded chip. We experimentally prove that it can be efficiently used to control the magnetic field needed to induce the nonreciprocal phase shift effect in the Ce:YIG. The fabricated devices exhibit extremely small footprint (<70 μm) and can be packaged, eliminating the need of a large size permanent magnet. A large Optical isolation of 32 dB and 11 dB is measured for the isolator and the circulator, respectively. Moreover, a two microring solution is also investigated to provide larger bandwidth and higher isolation. The proposed approach represents a promising solution for large-scale integration of nonreciprocal components in silicon photonics.

  • athermal operation of a waveguide Optical isolator based on canceling phase deviations in a mach zehnder interferometer
    Journal of Lightwave Technology, 2016
    Co-Authors: Kotoko Furuya, Yuya Shoji, Keita Kato, Takaya Nemoto, Tetsuya Mizumoto
    Abstract:

    Optical Isolators play unique roles in photonic circuits. We have developed an Optical isolator with silicon waveguides, based on a Mach–Zehnder interferometer. The device characteristics were temperature dependent. We investigated the temperature dependence of the refractive index ( ${\rm d}n/{\rm d}T$ ) and the magneto-Optical coefficient ( ${\rm d}\theta _f /{\rm d}T$ ) of a magneto-Optical garnet Ce:YIG, and estimated these as $9.1 \times 10^{-5}$ K−1 and 44 ${\rm }^\circ \cdot {\rm cm}^{- 1} \cdot {\rm K}^{- 1} $ , respectively. We discuss the design of an athermal silicon waveguide Optical isolator, in which the temperature dependences of the magneto-Optical effect and refractive indices are canceled in the backward direction. The high Optical isolation, greater than 20 dB, is demonstrated for temperature in the 20–60 °C range.

  • integrated magneto Optical materials and Isolators a review
    IEEE Photonics Journal, 2014
    Co-Authors: Bethanie J H Stadler, Tetsuya Mizumoto
    Abstract:

    Many novel materials and device designs have been proposed as photonic analogs to electrical diodes over the last four decades. This paper seeks to revisit these materials and designs as advanced technologies may enable experimental realization that was not possible upon conception of several of these designs. The background behind integration challenges, including waveguide birefringence, fabrication tolerances, garnet/semiconductor mismatch, and optimized interfaces will hopefully spark new ideas that will finally enable the realization of integrated Optical Isolators and circulators.

Masakatsu Okada - One of the best experts on this subject based on the ideXlab platform.

Min Xiao - One of the best experts on this subject based on the ideXlab platform.

  • cavity free Optical Isolators and circulators using a chiral cross kerr nonlinearity
    Physical Review Letters, 2018
    Co-Authors: Keyu Xia, Franco Nori, Min Xiao
    Abstract:

    Optical nonlinearity has been widely used to try to produce Optical Isolators. However, this is very difficult to achieve due to dynamical reciprocity. Here, we show the use of the chiral cross-Kerr nonlinearity of atoms at room temperature to realize Optical isolation, circumventing dynamical reciprocity. In our approach, the chiral cross-Kerr nonlinearity is induced by the thermal motion of $N$-type atoms. The resulting cross phase shift and absorption of a weak probe field are dependent on its propagation direction. This proposed Optical isolator can achieve more than 30 dB of isolation ratio, with a low loss of less than 1 dB. By inserting this atomic medium in a Mach-Zehnder interferometer, we further propose a four-port Optical circulator with a fidelity larger than 0.9 and an average insertion loss less than 1.6 dB. Using atomic vapor embedded in an on-chip waveguide, our method may provide chip-compatible Optical isolation at the single-photon level of a probe field.

  • parity time symmetry and variable Optical isolation in active passive coupled microresonators
    Nature Photonics, 2014
    Co-Authors: Long Chang, Min Xiao, Xiaoshun Jiang, Shiyue Hua, Chao Yang, Jianming Wen, Liang Jiang, Guanyu Li, Guanzhong Wang
    Abstract:

    On-chip parity–time-symmetric optics is experimentally demonstrated at a wavelength of 1,550 nm in two directly coupled, high-Q silica microtoroid resonators with balanced effective gain and loss. Switchable Optical isolation with a nonreciprocal isolation ratio between −8 dB and +8 dB is also shown. The findings will be useful for potential applications in Optical Isolators, on-chip light control and Optical communications.

  • parity time symmetry and variable Optical isolation in active passive coupled microresonators
    Nature Photonics, 2014
    Co-Authors: Long Chang, Min Xiao, Xiaoshun Jiang, Shiyue Hua, Chao Yang, Jianming Wen, Liang Jiang, Guanzhong Wang
    Abstract:

    On-chip parity–time-symmetric optics is experimentally demonstrated at a wavelength of 1,550 nm in two directly coupled, high-Q silica microtoroid resonators with balanced effective gain and loss. Switchable Optical isolation with a nonreciprocal isolation ratio between −8 dB and +8 dB is also shown. The findings will be useful for potential applications in Optical Isolators, on-chip light control and Optical communications. Compound-photonic structures with gain and loss1 provide a powerful platform for testing various theoretical proposals on non-Hermitian parity–time-symmetric quantum mechanics2,3,4,5 and initiate new possibilities for shaping Optical beams and pulses beyond conservative structures. Such structures can be designed as Optical analogues of complex parity–time-symmetric potentials with real spectra. However, the beam dynamics can exhibit unique features distinct from conservative systems due to non-trivial wave interference and phase-transition effects. Here, we experimentally realize parity–time-symmetric optics on a chip at the 1,550 nm wavelength in two directly coupled high-Q silica-microtoroid resonators with balanced effective gain and loss. With this composite system, we further implement switchable Optical isolation with a non-reciprocal isolation ratio from −8 dB to +8 dB, by breaking time-reversal symmetry with gain-saturated nonlinearity in a large parameter-tunable space. Of importance, our scheme opens a door towards synthesizing novel microscale photonic structures for potential applications in Optical Isolators, on-chip light control and Optical communications.

Bethanie J H Stadler - One of the best experts on this subject based on the ideXlab platform.

  • magneto Optical materials and designs for integrated te and tm mode planar waveguide Isolators a review invited
    Optical Materials Express, 2018
    Co-Authors: K Srinivasan, Bethanie J H Stadler
    Abstract:

    Optical Isolators are unidirectional devices that employ the magneto-Optical (MO) property of iron garnets to block the reflected light in almost all Optical systems. Sputter deposition of either doped yttrium iron garnets (YIG) with seed-layers or seed-layer free terbium iron garnets (TIG) will help realize integrated planar Isolators. Faraday rotation waveguides are designed as a viable solution to enable these monolithically integrated garnets to overcome the limitations inherent to hybrid integration of interferometric devices. In fact, small footprint Faraday rotation devices have been achieved using doped TIG for both TE/TM modes with sufficiently low loss and large isolation ratios.

  • integrated magneto Optical materials and Isolators a review
    IEEE Photonics Journal, 2014
    Co-Authors: Bethanie J H Stadler, Tetsuya Mizumoto
    Abstract:

    Many novel materials and device designs have been proposed as photonic analogs to electrical diodes over the last four decades. This paper seeks to revisit these materials and designs as advanced technologies may enable experimental realization that was not possible upon conception of several of these designs. The background behind integration challenges, including waveguide birefringence, fabrication tolerances, garnet/semiconductor mismatch, and optimized interfaces will hopefully spark new ideas that will finally enable the realization of integrated Optical Isolators and circulators.

  • novel designs for integrating yig air photonic crystal slab polarizers with waveguide faraday rotators
    IEEE Photonics Technology Letters, 2005
    Co-Authors: Samir K Mondal, Bethanie J H Stadler
    Abstract:

    Photonic crystal slab waveguides (PCSWs), based on the novel magnetooptic material, yttrium iron garnet (YIG), have been designed in order to enable fully integrated Optical Isolators. The PCSWs possess fundamental bandgaps for even (transverse-electric (TE)-like) modes around the wavelength of 1.33 /spl mu/m. Propagation losses for both the TE-like and transverse-magnetic (TM)-like polarizations with various orientations have been investigated numerically using partial-wave analysis and a three-dimensional finite-difference time-domain method. The resulting PCSW designs can be used to isolate TE-like modes from TM-like modes and vice versa with isolation ratios of -60 and -40 dB, respectively. One of the main benefits of these designs is that they provide interface-free polarizers for the garnet waveguides. The designs can easily be extended to 1.55 /spl mu/m for further versatility.

Takenori Sekijima - One of the best experts on this subject based on the ideXlab platform.