Browsing by Author "Chen, H-S"

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Enhancement in speed and responsivity of uni-traveling carrier photodiodes with GaAs0.5Sb0.5/In0.53Ga0.47As type-II hybrid absorbers
(2019-05-27)
Naseem
;
Ahmad, Zohauddin
;
Chao, Rui-Lin
;
Chang, Hsiang-Szu
;
Ni, C-J
We demonstrate a top-illuminated high-speed uni-traveling carrier photodiode (UTC-PD) with a novel design in the p-type absorber, which call effectively shorten the photon absorption depth at telecommunication wavelengths (1.31 similar to 1.55 mu m) and further enhance the bandwidth-efficiency product of UTC-PD. In our proposed new UTC-PD structure, the p-type In0.53Ga0.47As absorption layer is replaced by the type-II GaAs0.5Sb0.5 (p)/In0.53Ga0.47As (i) hybrid absorber. Due to the narrowing of the bandgap and enhancement of the photo-absorption process at the type-II interface between the GaAs0.5Sb0.5 and In0.53Ga0.47As layers, our device shows an over 16.7% improvement in the responsivity compared with that of UTC-PD with the same thickness of pure In0.53Ga0.47As absorber (0.7 mu m) and a zero optical coupling loss. Our demonstrated device with a simple top-illuminated structure offers a large active mesa (25 mu m). a wide optical-to-electrical (O-E) bandwidth (33 GHz), a high responsivity (0.7 A/W), and a high saturation current (>5 mA) under 1.31 mu m optical wavelength. These promising results suggest that our proposed PD structure can fundamentally overcome the trade-off among bandwidth. efficiency. and device active diameter of high-speed PDs. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
High-Speed In0.52Al0.48As Based Avalanche Photodiode With Top-Illuminated Design for 100 Gb/s ER-4 System
(2018-12-01)
Wu, Song-Lin
;
Naseem
;
Wun, Jhih-Min
;
Chao, Rui-Lin
;
Huang, Jack Jia-Sheng
High-speed top-illuminated avalanche photodiodes (APDs) with large diameters (25 mu m) are demonstrated for the application of 4-channels 100 Gb/s data rate. They achieve a bandwidth of 17 GHz at low-gain (M-G = 6.2; 3.6 A/W) and large-gain bandwidth (responsivity bandwidth) product (410 GHz (237.8 GHz-A/W); 55% external efficiency at the unit gain) while maintaining invariant high speed (14 GHz) under high power (0.5 mW) and 0.9 V-b(r) operations. By packaging the demonstrated APD with a 25 Gb/s transimpedance amplifier in a 100 Gb/s ROSA package, a good sensitivity of around -20.6 dBm optical modulation amplitude (OMA) at the data rate of 25.78 Gb/s has been successfully demonstrated. The achieved sensitivity not only meets the required receiver sensitivity (-18.5 dBm OMA) in 100 GbE-ER-4 Lite (40 km) system, it is also comparable with that of the high-performance 1(N) Gb/s ROSA incorporated with the backside illuminated APD design. Overall, our novel APD structure can eliminate the costly flip-chip bonding package in the 100 Gb/s ROSA without sacrificing its sensitivity performance.