北京邮电大学信息光子学与光通信国家重点实验室,北京 100876
光通信系统不断提升的传输速率对光电探测器的带宽提出了更高的要求。利用有限元分析软件APSYS对p区倒置型雪崩光电探测器(APD)进行设计与优化。结果表明,双台面p区倒置型 APD可将电场限制在中心区域,避免器件发生边缘击穿,器件的暗电流约为0.1 nA,最大带宽为23 GHz,增益带宽积为276 GHz。在此结构上,对双台面p区倒置型 APD的台面及层结构参数进行优化,得到最大带宽为31.7 GHz,增益带宽积为289.4 GHz的三台面p区倒置型 APD。
光通信 光电探测器 p区倒置型雪崩光电探测器 台面结构 增益带宽积 中国激光
2022, 49(13): 1306002
Author Affiliations
Abstract
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
We designed a tunable wavelength-selective quasi-resonant cavity enhanced photodetector (QRCE-PD) based on a high-contrast subwavelength grating (SWG). According to simulation results, its peak quantum efficiency is 93.2%, the 3 dB bandwidth is 33.5 GHz, the spectral linewidth is 0.12 nm, and the wavelength-tuning range is 28 nm (1536–1564 nm). The QRCE-PD contains a tunable Fabry–Perot (F-P) filtering cavity (FPC), a symmetrical SWG deflection reflector (SSWG-DR), and a built-in p-i-n photodiode. The FPC and the SSWG-DR form an equivalent multi-region F-P cavity together by multiple mutual mirroring, which makes the QRCE-PD a multi-region resonant cavity enhanced photodetector. But, QRCE-PD relies on the multiple-pass absorption enhanced effect to achieve high quantum efficiency, rather than the resonant cavity enhanced effect. This new photodetector structure is significant for the application in the dense wavelength division multiplexing systems.
photodetector quasi-resonant cavity subwavelength grating ultra-narrow linewidth Chinese Optics Letters
2022, 20(3): 031301
Author Affiliations
Abstract
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
Linearity is a very important parameter to measure the performance of avalanche photodiodes (APDs) under high input optical power. In this paper, the influence of the absorption layer on the linearity of APDs is carefully studied by using bandgap engineering with the structure model of separated absorption, grading, charge, multiplication, charge, and transit (SAGCMCT). The simulated results show that in the hybrid absorption layer device structure the 1 dB compression point can be improved from to by increasing the proportion of the -type absorption layer. In the device structure with only one absorption layer, increasing the doping level of the absorption layer can also improve the 1 dB compression point from to 1.43 dBm at a gain of 10. Therefore, the absorption layer is very critical for the linearity of APDs.
linearity avalanche photodiode dynamic range Chinese Optics Letters
2022, 20(2): 022503
Author Affiliations
Abstract
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
We proposed a method to form a flat transmitted serrated-phase (SP) high-contrast-index subwavelength grating (HCG) beam splitter (HBS) for all dielectric materials, which is to alternately arrange two kinds of grating bars with a phase difference of . Compared to the typical linear-phase (LP) HBS, which consists of two symmetrical deflecting gratings, the SP-HBS is extensible in size, and can achieve excellent splitting ability regardless of normal incidence or small-angle oblique incidence with large deflection angles, higher diffraction efficiency, lower energy loss, and higher tolerance of fabrication accuracy. Furthermore, the incident light can be split in half at any part of the SP-HBS, and the output beams of light maintain the original shape. In this Letter, we designed an SP-HBS with a 44.8° deflection angle and a 90.28% transmissivity.
beam splitter high-contrast-index subwavelength grating serrated-phase profile splitting ability Chinese Optics Letters
2020, 18(11): 110504
Author Affiliations
Abstract
Institute of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
We have designed and fabricated zero-bias operational two-element symmetric-connected photodetector arrays (SC-PDAs). The designed SC-PDAs have higher saturation currents, larger RF power, and better frequency responses than the single photodetector (PD) under zero bias. The bias-free SC-PDA with 15 μm diameter of each PD demonstrated a 3 dB bandwidth of 19.4 GHz at 0.5 mA. The RF saturation photocurrent and maximum RF output power of the SC-PDA with 40 μm, 50 μm, and 60 μm diameters under zero bias are over 9.31 mA and ?5.86 dBm at 3 GHz, 14.52 mA and 1.17 dBm at 1 GHz, and 13.72 mA and ?1.76 dBm at 1 GHz, respectively.
photodetectors photodiode array microwave photonics Chinese Optics Letters
2020, 18(1): 012501
北京邮电大学信息光子学与光通信国家重点实验室, 北京 100876
在PIN光电探测器(PIN-PD)结构的垂直方向上集成垂直腔面发射激光器(VCSEL)结构单元,实现了收发一体式工作的集成光电芯片对,可用于进一步提高光互连的性能。该集成光电芯片可以同时对两个波段进行收发一体工作,一端进行中心波长为805 nm的光信号的发送和中心波长为850 nm的光信号的接收,另一端进行中心波长为850 nm的光信号的发送和中心波长为805 nm的光信号接收。仿真优化805 nm波长处光信号发送端的结构与性能,理论分析结构中VCSEL单元和PIN-PD单元工作时的电学隔离和光学解耦,最终证实本结构可以同时进行收发一体的工作。
光通信 光电集成 光电探测器 激光器 垂直腔面发射激光器 光互连
Author Affiliations
Abstract
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
An integrated optoelectronic chip pair, which can transmit and receive optical signals simultaneously, is proposed in this Letter. The design and optimization of its key structure, the vertical cavity surface emitting laser’s distributed Bragg reflector, are presented. Analysis is also done for its influence on the integrated chip’s performance. Moreover, the chip pair’s performance under dynamic conditions is analyzed. Their 3 dB modulation bandwidths are higher than 10 GHz, and their 3 dB photo-response bandwidths are around 23 GHz. Their applications will further improve the performances of the optical interconnects.
130.3120 Integrated optics devices 130.0250 Optoelectronics 250.7260 Vertical cavity surface emitting lasers Chinese Optics Letters
2019, 17(4): 041301
Author Affiliations
Abstract
Institute of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
The fabrication and characterization of p-i-n photodiodes integrated with wide spectrum focusing reflectors using nonperiodic strip and concentric-circular subwavelength gratings are presented. The experimental results show that the gratings can reflect and focus the incident light on the absorber of the photodiode, and thus can simultaneously achieve high speed and high efficiency. For the gratings’ integrated photodiodes, the responsivity is improved over a wide spectral range, and when the absorber was 600 nm and the mesa diameter was 40 μm, a responsivity of 0.46 A/W at a wavelength of 1.55 μm and a 3 dB bandwidth of 21.6 GHz under a reverse bias of 3 V were simultaneously obtained.
130.3120 Integrated optics devices 230.5170 Photodiodes Chinese Optics Letters
2018, 16(5): 051301
Author Affiliations
Abstract
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China
In this Letter, a pair of integrated optoelectronic transceiving chips is proposed. They are constructed by integrating a vertical cavity surface emitting laser unit above a positive-intrinsic-negative photodetector unit. One of the transceiving chips emits light at the wavelength of 848.1 nm with a threshold current of 0.8 mA and a slope efficiency of 0.81 W/A. It receives light between 801 and 814 nm with a quantum efficiency of higher than 70%. On its counterpart, the other one of the transceiving chips emits light at the wavelength of 805.3 nm with a threshold current of 1.1 mA and a slope efficiency of 0.86 W/A. It receives light between 838 and 855 nm with a quantum efficiency of higher than 70%. The proposed pair of integrated optoelectronic transceiving chips can work full-duplex with each other, and they can be applied to single fiber bidirectional optical interconnects.
130.3120 Integrated optics devices 130.0250 Optoelectronics 250.7260 Vertical cavity surface emitting lasers Chinese Optics Letters
2018, 16(9): 091301