We report the high-density light-emitting diode (LED) array using a lateral p-n junction. Al_xGa_1-xAs lateral p-n junctions were formed on a semi-insulating GaAs (311)A patterned substrate using the amphoteric nature of silicon that behaves as p- and n-type dopant. For the first time, 2400 dots-per-inch (dpi) LED arrays were fabricated using the lateral junction. Electroluminescence spectrum shows a single peak at a wavelength of 813nm with an FWHM of 56nm at room temperature. The light output power was measured as a function of forward injection current. The high-density LED array has potential application in LED printers and displays.

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In this article, a new algorithm that takes the truth vector of a 5-valued function as its input and proceeds to generate all of the function's fixed polarity Reed-Muller (FPRM) spectral coefficient vectors one by one in a certain sequence is presented. The experimental results for this algorithm are compared with other methods and it was found that it is more efficient than other methods for some functions. Moreover, the presented algorithm requires very low memory storage.

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A highly efficient and low noise gain-clamped long-wavelength-band erbium-doped fiber amplifier (L-band EDFA) is demonstrated using a ring laser in double-pass system. The broadband fiber Bragg grating (FBG) operating at L-band region is used to retro-pass the test signal into the system for enhanced gain. A length of forward pumped EDF is incorporated in front of the double-pass amplifier to achieve a low noise figure. The gain clamping is achieved by routing the backward ASE into the feedback loop to create ring laser. The gain is clamped at 18.6dB from -40 to -8dBm with gain variation of less than ±0.1dB and a noise figure of less than 6dB.

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We have proposed a new phase-controlled distributed feedback wavelength tunable optical filter with distributed coupling coefficient. The analysis, which is based on the transfer matrix method, reveals that an almost constant peak transmissivity (gain) of more than 37dB, tuning range of better than 21.7Å and side-mode suppression ratio (SMSR) of more than 17dB can be achieved using this structure.

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This letter presents a mathematical formulation that clearly explains the result that was heuristically introduced by Leeson for the oscillator noise spectrum. We consider the voltage and current in a simple equivalent circuit consisting of only linear components. To analyze both the oscillation and noise behaviors simultaneously without resort to frequency-domain transfer functions, we introduce dual coordinates in the time domain. Equivalent device temperature and Q factor are appropriately defined to support Leeson's result. It is successfully clarified, without taking any nonlinear effects into account, that the noise from a white source is converted up into a sharp spectrum around the oscillation frequency.

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