Annotation of the Eucalyptus grandis genome showed a large amplification of the dehydration-responsive element binding 1/C-repeat binding factor (DREB1/CBF) group without recent DREB2 gene duplication compared with other plant species. The present annotation of the CBF and DREB2 genes from a draft of the Eucalyptus gunnii genome sequence reveals at least one additional CBF copy in the E. gunnii genome compared with E.
View Article and Find Full Text PDFMach-Zehnder optical modulators are the key devices for high-speed electrical-to-optical conversion in Si photonics. Si rib waveguides with a p-n diode structure operated in the carrier depletion mode have mainly been developed as their phase shifters. Their length is usually longer than millimeters due to the limited change in the refractive index due to the carrier depletion in a Si p-n diode.
View Article and Find Full Text PDFWe demonstrate the high-speed electrical delay tuning of slow light pulses using Si photonic crystal waveguides. The device has an i-region-chirped pin diode, within which thermo-optic and carrier plasma effects are generated by forward bias. The former changes the delay up to 62 ps for the DC bias.
View Article and Find Full Text PDFWe demonstrate the first sub-100 μm silicon Mach-Zehnder modulators (MZMs) that operate at >10 Gb/s, by exploiting low-dispersion slow-light in lattice-shifted photonic crystal waveguides (LSPCWs). We use two LSPCW-MZM structures, one with LSPCWs in both arms of the MZM, and the other with an LSPCW in only one of the arms. Using the first structure we demonstrate 10 Gb/s operation with a operating bandwidth of 12.
View Article and Find Full Text PDFWe report a silicon DQPSK receiver whose symbol rate can be varied by a tunable one-bit delay line including an all-pass micro-ring slow-light device. It also consists of Si-wire waveguides with spot-size converters, optimized splitters/couplers, heater-controlled Mach-Zehnder attenuators and phase shifters, 90° hybrid with a low-loss crossing and balanced Ge photodiodes, all of which are fabricated by using CMOS-compatible process. Demodulation was confirmed at symbol-rates of 7.
View Article and Find Full Text PDFWe report the first experimental demonstration of 10 Gb/s modulation in a photonic crystal silicon optical modulator. The device consists of a 200 μm-long SiO2-clad photonic crystal waveguide, with an embedded p-n junction, incorporated into an asymmetric Mach-Zehnder interferometer. The device is integrated on a SOI chip and fabricated by CMOS-compatible processes.
View Article and Find Full Text PDFWe demonstrate tapering of a high air-fill fraction photonic crystal fiber by using the flame-brushing technique. Transverse probing along the taper allows us to ascertain how the microstructure is preserved during tapering. Experimental results are compared with numerical simulations performed with the finite-difference time-domain and plane-wave expansion methods.
View Article and Find Full Text PDFWe report detailed measurements of the optical properties of tapered photonic crystal fibers (PCFs). We observe a striking long-wavelength loss as the fiber diameter is reduced, despite the minimal airhole collapse along the taper. We associate this loss with a transition of the fundamental core mode as the fiber dimensions contract: At wavelengths shorter than this transition wavelength, the core mode is strongly confined in the fiber microstructure, whereas at longer wavelengths the mode expands beyond the microstructure and couples out to higher-order modes.
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