Jung-ki Kim

Spot-size converter integrated polarization insensitive semiconductor optical amplifiers

Spot-size converter integrated polarization-insensitive semiconductor optical amplifier (SSC-SOA) with angled window has been designed and fabricated using both selective area growth and successive lateral tapering. A narrow beam divergence of 80/spl times/15/spl deg/, 0.2-dB amplified-spontaneous-emission ripple, and 1.5-dB polarization sensitivity within the 3-dB optical bandwidth were obtained at 29.7-dB chip gain. The fiber-to-fiber gain of the SOA module was measured to be 22 dB at 200 mA, i.e., the coupling loss was below 4 dB per each facet.

Analysis of Failure Mechanisms and Extraction of Activation Energies

In this letter, we point out the methodological problem of the conventional temperature-accelerated life-test method of nand Flash memory. We confirm that the generally assumed Arrhenius law is inconsistent with extrapolation of data-retention time-to-failure of nand Flash memory since several failure mechanisms come up together. For the first time, we completely separated three main failure mechanisms and extracted each activation energy (Ea) in 21-nm nand Flash memory. From the results, we assured that each failure mechanism follows the Arrhenius law. In order to estimate the lifetime of nand Flash memory accurately, each failure mechanism should be considered.