摘要： The design, analysis, and demonstration of flip-chip bonding packaged uni-traveling-carrier photodiodes (UTC-PDs) with THz (dc to 315 GHz) 3-dB bandwidth and high-power performance are reported. The high-frequency roll-off (up to 0.4 THz) of the flip-chip bonding structure and device heating under high power operation are both minimized through properly downscaling the area of the bonding pad and minimizing the solder distance to the active area of the miniaturized UTC-PD. In order to suppress the serious space-charge screening effect in miniaturized UTC-PDs under high-current density (∼180 kA/cm 2 ) operation, an n-type charge layer is inserted into the collector. The detailed dynamic measurement results of these packaged PD modules indicate that non-equilibrium electron transport plays an important role in determining the maximum speed and THz output power. In addition, a femtosecond (fs) optical pulse train generator with a ∼300 fs pulse-width output and repetition rate up to ∼0.3 THz is also developed to further boost the photo-generated THz-power. Compared with using an optical signal with a sinusoidal envelope for PD excitation, the short-pulse approach can offer a 3-dB enhancement in output power under the same output photocurrent and operating frequency (around 0.3 THz). By utilizing such an fs light source and our PD module, a continuous wave output power as high as 1 mW at an operating frequency of ∼0.3 THz is successfully demonstrated. 其他題名： JLT 出版者： New York: IEEE 出版日期： 2016-02-15 出處： Journal of lightwave technology, 2016-02, Vol.34 (4), p.1387-1397 資源來源： IEEE Xplore 版權： Copyright The Institute of Electrical and Electronics Engineers, Inc. (IEEE) 2016 識別號： ISSN: 0733-8724 識別號： EISSN: 1558-2213 識別號： DOI: 10.1109/JLT.2015.2503778 識別號： CODEN: JLTEDG
