Si~C-SiC Multiple Quantum Barrier High Speed, Wide-Band Avalanche Photodiodes

2018 ◽  
Author(s):  
Somrita Ghosh ◽  
Aritra Acharyya
Keyword(s):  
High Speed ◽  
Avalanche Photodiodes ◽  
Wide Band ◽  
Multiple Quantum

HIGH SPEED RESONANT-CAVITY InGaAs/InAlAs AVALANCHE PHOTODIODES

2000 ◽  
Vol 10 (01) ◽  
pp. 327-337
Author(s):  
J. C. CAMPBELL ◽  
H. NIE ◽  
C. LENOX ◽  
G. KINSEY ◽  
P. YUAN ◽  
...  
Keyword(s):  
High Speed ◽  
Impact Ionization ◽  
Avalanche Photodiodes ◽  
Resonant Cavity ◽  
Multiple Quantum Well ◽  
Low Noise ◽  
Excess Noise ◽  
Multiple Quantum ◽  
Gain Bandwidth ◽  
Unity Gain

The evolution of long-haul optical fiber telecommunications systems to bit rates greater than 10 GB/s has created a need for avalanche photodiodes (APDs) with higher bandwidths and higher gain-bandwidth products than are currently available. It is also desirable to maintain good quantum efficiency and low excess noise. At present, the best performance (f3dB ~ 15 GHz at low gain and gain-bandwidth product ~ 150 GHz) has been achieved by AlInAs/InGaAs(P) multiple quantum well (MQW) APDs. In this paper we report a resonant-cavity InAlAs/InGaAs APD that operates near 1.55 μm. These APDs have achieved very low noise (k equivalent to 0.18) as a result of the very thin multiplication regions that were utilized. The low noise is explained in terms of a new model that accounts for the non-local nature of impact ionization. A unity-gain bandwith of 24 GHz and a gain-bandwidth-product of 290 GHz were achieved.

Multiple Quantum Barrier Nano-avalanche Photodiodes - Part III: Time and Frequency Responses

2019 ◽  
Vol 9 (2) ◽  
pp. 192-197
Author(s):  
Somrita Ghosh ◽  
Aritra Acharyya
Keyword(s):  
Optical Pulse ◽  
Pulse Current ◽  
Avalanche Photodiodes ◽  
Simulation Method ◽  
Rectangular Pulse ◽  
Operating Conditions ◽  
Multiple Quantum ◽  
Material System ◽  
Frequency Responses ◽  
The Fourier Transform

Background: The time and frequency responses of Multiple Quantum Barrier (MQB) nano-scale Avalanche Photodiodes (APDs) based on Si~3C-SiC material system have been investigated in this final part. Methods: A very narrow rectangular pulse of pulse-width of 0.4 ps has been used as the input optical pulse having 850 nm wavelength incidents on the p+-side of the MQB APD structures and corresponding current responses have been calculated by using a simulation method developed by the authors. Results: Finally the frequency responses of the devices are obtained via the Fourier transform of the corresponding pulse current responses in time domain. Conclusion: Simulation results show that MQB nano-APDs possess significantly faster time response and wider frequency response as compared to the flat Si nano-APDs under similar operating conditions.

High-speed flip-chip InP/InGaAs avalanche photodiodes with ultralow capacitance and large gain-bandwidth products

1991 ◽  
Vol 3 (12) ◽  
pp. 1115-1116 ◽  
Author(s):  
Y. Kito ◽  
H. Kuwatsuka ◽  
T. Kumai ◽  
M. Makiuchi ◽  
T. Uchida ◽  
...  
Keyword(s):  
High Speed ◽  
Flip Chip ◽  
Avalanche Photodiodes ◽  
Gain Bandwidth ◽  
Large Gain

MBE growth and characterization of doped multiple quantum well avalanche photodiodes

1997 ◽  
Vol 175-176 ◽  
pp. 983-989 ◽  
Author(s):  
H.M. Menkara ◽  
R.N. Bicknell-Tassius ◽  
R. Benz ◽  
C.J. Summers
Keyword(s):  
Quantum Well ◽  
Avalanche Photodiodes ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Mbe Growth

Design of a multi-function high-speed digital baseband data acquisition system

2021 ◽  
Vol 21 (10) ◽  
pp. 248
Author(s):  
Xin Pei ◽  
Jian Li ◽  
Na Wang ◽  
Toktonur Ergesh ◽  
Xue-Feng Duan ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Radio Telescope ◽  
High Speed ◽  
Single Channel ◽  
Wide Band ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Single Server ◽  
Long Baseline ◽  
Digital Baseband

Abstract A multi-function digital baseband data acquisition system is designed for the sampling, distribution and recording of wide-band multi-channel astronomical signals. The system hires a SNAP2 board as a digital baseband converter to digitize, channelize and packetize the received signal. It can be configured dynamically from a single channel to eight channels with a maximum bandwidth of 4096 MHz. Eight parallel HASHPIPE instances run on four servers, each carrying two NVMe SSD cards, achieving a total continuous write rate of 8 GB s−1. Data are recorded in the standard VDIF file format. The system is deployed on a 25-meter radio telescope to verify its functionality based on pulsar observations. Our results indicate that during the 30-minute observation period, the system achieved zero data loss at a data recording rate of 1 GB s−1 on a single server. The system will serve as a verification platform for testing the functions of the QTT (QiTai radio Telescope) digital backend system. In addition, it can be used as a baseband/VLBI (Very Long Baseline Interferometry) recorder or D-F-engine of correlator/beamformer as well.

Using Wavelet Analysis to Distinguish Cavitation Acoustic Emissions From Blunt Impact Noise

2021 ◽  
Author(s):  
Christopher Eckersley ◽  
Joost Op 't Eynde ◽  
Mitchell Abrams ◽  
Cameron R. Bass
Keyword(s):  
Wavelet Transform ◽  
High Speed ◽  
Acoustic Noise ◽  
Bubble Formation ◽  
Acoustic Emissions ◽  
Wide Band ◽  
Water Tank ◽  
Impact Noise ◽  
Blunt Impact

Abstract Cavitation has been shown to have implications for head injury, but currently there is no solution for detecting the formation of cavitation through the skull during blunt impact. The goal of this communication is to confirm the wideband acoustic wavelet signature of cavitation collapse, and determine that this signature can be differentiated from the noise of a blunt impact. A controlled, laser induced cavitation study was conducted in an isolated water tank to confirm the wide band acoustic signature of cavitation collapse in the absence of a blunt impact. A clear acrylic surrogate head was impacted to induce blunt impact cavitation. The bubble formation was imaged using a high speed camera, and the collapse was synched up with the wavelet transform of the acoustic emission. Wideband acoustic response is seen in wavelet transform of positive laser induced cavitation tests, but absent in laser induced negative controls. Clear acrylic surrogate tests showed the wideband acoustic wavelet signature of collapse can be differentiated from acoustic noise generated by a blunt impact. Broadband acoustic signal can be used as a biomarker to detect the incidence of cavitation through the skull as it consists of frequencies that are low enough to potentially pass through the skull but high enough to differentiate from blunt impact noise. This lays the foundation for a vital tool to conduct CSF cavitation research in-vivo.

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