We demonstrate novel structures of a vertical-cavity surface-emitting laser (VCSEL) for high-speed (∼40 Gbit/s) operation with ultralow power consumption performance. Downscaling the size of oxide aperture of VCSELs is one of the most effective ways to reduce the power consumption during high-speed operation. However, such miniaturized oxide apertures (∼2 μm diameter) in VCSELs will result in a large differential resistance, optical single-mode output, and a small maximum output power (< 1 mW). These characteristics seriously limit the maximum electrical-to-optical (E-O) bandwidth and device reliability. By the use of the oxide-relief and Zn-diffusion techniques in our demonstrated 850-nm VCSELs, we can not only release the burden imposed on downscaling the current-confined aperture for high speed with low-power consumption performance, but can also manipulate the number of optical modes inside the cavity to maximize the E-O bandwidth and product of bit-rate transmission distance in an OM4 fiber. State-of-the-art dynamic performances at both room temperature and 85 • C operations can be achieved by the use of our device. These include extremely high D-factors (∼13.5 GHz/mA 1 /2 ), as well as record-low energy-to-data ratios (EDR: 140 fJ/bit) at 34 Gbit/s operation, and error-free transmission over a 0.8-km OM4 multimode fiber with a record-low energyto-data distance ratio (EDDR: 175.5 fJ/bit.km) at 25 Gbit/s.
Typical white LED has limited energy beyond the band of (420-720) nm, which is not suitable as a transferring standard for spectral radiant flux, spectral irradiance. An extended wavelength LED has enough spectral intensity in the whole visible range has been developed, by six LED dies and RGB phosphor. The spectrum and stability of the developed LED was evaluated and the possibility of it to be used as luminous flux lamp was studied in a 2m integrating sphere-spectroradiometer, the testing result shows it could be worked as a reference standard for transferring spectral radiant flux to calibrate the luminous flux for generally used LED inside the range of uncertainty.
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