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Titanium dioxide (TiO2) has been widely studied as an inexpensive and efficient electrochromic material. However, slow response speed and poor cycling performance still constrain the further application of TiO2 electrochromic materials. In this work, a series of cobalt-doped TiO2 electrochromic films were fabricated via hydrothermal method combined with a spin-coated approach. The effects of doped cobalt ions on the electrochemical and electrochromic performance of TiO2 were explored. The cobalt-doping concentrations on the morphology and electrochromic performance of the samples were investigated by means of XRD, XPS, FESEM, HR-TEM, and electrochemical techniques. It is found that the ionic diffusion coefficient of the 0.5% Co-TiO2 composite film is 6.44 × 10−10 cm2/s, the coloring efficiency is 34.11 cm2/C, and the coloring and bleaching switching time are 1.92 s and 10.71 s, respectively. Moreover, the 0.5% and 1% Co-TiO2 composite films showed superior cyclic performance than pristine TiO2. This indicates that the appropriate amount of Co doping can significantly enhance the electrochromic properties of titanium dioxide films. [ABSTRACT FROM AUTHOR]

In order to improve the performance of fiber network, not only higher quality factor and minimum bit error rate required but also the role of ER cannot be neglected. Since, only the treatment of linear and nonlinear impairments are not sufficient, there must be a need of degradation of signal leakage through the optical fiber networks related to the extinction ratio. Also, the extinction ratio is the significant parameter to measure the optical signal quality of the transmitter and receiver. Therefore, this research is to investigate that how much the effect of ER on the performance of fiber optic networks based on Optisystem 0.17 designed with EDFA and DWDM technology. [ABSTRACT FROM AUTHOR]

In this article, we demonstrate a push-pull silicon dual-ring modulator based on two cascaded rings which are coupled with each other through two parallel bus waveguides. In the transmission spectrum of the modulator, a narrow transparency peak exists in the center of the broad dip based on the electromagnetically induced transparency (EIT)-like effect. Benefiting from both the EIT-like effect and push-pull drive configuration, a low insertion loss (IL) of 1.4 dB and an extinction ratio (ER) over 6.4 dB are obtained at a bit rate of 10 Gb/s with a peak-to-peak driving voltage (Vpp) of 5 V. The corresponding maximum optical modulation amplitude (OMA) is 0.56, which is almost twice that of a single micro-ring modulator with the same driving voltage. Moreover, the maximum OMA is 0.47 at 20 Gb/s, which is 81% larger than that of a single micro-ring modulator. [ABSTRACT FROM AUTHOR]

We present results from an investigation of the energy efficiency of vertical cavity surface emitting lasers (VCSELs) under large signal modulation. We show that the most important factor influencing the energy consumption of the VCSELs is the required optical modulation amplitude, which drives other VCSEL design requirements. The required optical modulation amplitude also depends on the optical link design. Through this dependence, it is possible to better understand the energy consumption of complete short-range optical links. [ABSTRACT FROM PUBLISHER]

100 Gbit/s operation of a 1.3 μm, 4‐channel directly modulated laser (DML) array monolithically integrated multimode interference (MMI) coupler is demonstrated for the first time. An optical modulation amplitude exceeding −0.7 dBm and clear eye openings are achieved at 55°C under simultaneous operation. [ABSTRACT FROM AUTHOR]