250 km nonrepeated transmission experiment at 1.8 Gb/s using LD pumped Er3+-doped fibre amplifiers in IM/direct detection system

1989 ◽  
Vol 25 (10) ◽  
pp. 662-664 ◽  
Author(s):  
K. Hagimoto ◽  
K. Iwatsuki ◽  
A. Takada ◽  
M. Nakazawa ◽  
M. Saruwatari ◽  
...  
Keyword(s):  
Direct Detection ◽  
Detection System ◽  
Transmission Experiment ◽  
Fibre Amplifiers

Transmission length improvement in 2.5 Gbit/s direct detection system with Er-doped fibre amplifiers by efficient remote pumping

1991 ◽  
Vol 27 (17) ◽  
pp. 1537 ◽  
Author(s):  
T. Rasmussen ◽  
A. Bjarklev ◽  
J. Hedegaard povlsen ◽  
O. Lumholt ◽  
K. Rottwitt
Keyword(s):  
Direct Detection ◽  
Detection System ◽  
Transmission Length ◽  
Fibre Amplifiers ◽  
Er Doped

scholarly journals Imbalanced Mach-Zehnder Modulator for Fading Suppression in Dispersion-Uncompensated Direct Detection System

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2866
Author(s):  
Yixiao Zhu ◽  
Xin Miao ◽  
Qi Wu ◽  
Longjie Yin ◽  
Weisheng Hu
Keyword(s):  
Forward Error Correction ◽  
Direct Detection ◽  
Detection System ◽  
Single Mode ◽  
Pulse Amplitude ◽  
Single Mode Fiber ◽  
Error Rates ◽  
Transmission Experiment ◽  
Mach Zehnder Modulator ◽  
The Impact

In this work, we systematically analyze the impact of three kinds of Mach-Zehnder modulator (MZM) imbalances, including bias deviation, amplitude mismatch, and differential time skew in intensity-modulation direct-detection (IM-DD) links. It is shown that, for power fading limited transmission, the imbalances can be utilized as advantages rather than impairments. Specifically, the bias deviation with single-arm driven mode and amplitude mismatch with differential driven mode can increase the available bandwidth by shifting the frequency of fading notches. Meanwhile, time skew provides another way to avoid fading by shaping the double sideband (DSB) signal into a vestigial sideband (VSB) with an asymmetrical transfer function. In the transmission experiment, 34 Gbaud Nyquist 6/8-ary pulse amplitude modulation (PAM-6/8) signals are used for investigation in a 20 km dispersion-uncompensated standard single-mode fiber (SSMF) link. With the help of a Volterra nonlinear equalizer, all three kinds of imbalances can achieve bit-error rates (BERs) below the 7% and 20% hard-decision forward error correction (HD-FEC) thresholds for PAM-6 and PAM-8 signals, respectively. The received power sensitivity is also compared at the back-to-back (BTB) case and after fiber transmission. Both numerical simulation and experimental demonstration confirm that the dispersion-induced power fading can be effectively suppressed with bias, amplitude, or skew imbalance, providing a feasible solution for transmission distance extension of C-band DD links.

Direct Detection System forEscherichia coliUsing Au–Ag Alloy Microchips

2013 ◽  
Vol 52 (22) ◽  
pp. 7282-7288 ◽  
Author(s):  
Wan-Joong Kim ◽  
Sanghee Kim ◽  
Ae Rhan Kim ◽  
Dong Jin Yoo
Keyword(s):  
Direct Detection ◽  
Detection System

scholarly journals GEM-Based Detectors for Direct Detection of Low-Mass WIMP, Solar Axions and Narrow Resonances (Quarks)

2021 ◽  
Author(s):  
Victor Parusov ◽  
Boris Ovchinnikov
Keyword(s):  
Direct Detection ◽  
Detection System ◽  
Beta Particle ◽  
Gaseous Mixtures ◽  
Low Mass ◽  
Nonzero Spin ◽  
Time Projection ◽  
First Time ◽  
Solar Axions ◽  
Low Mass Wimp

Gas electron multipliers (GEMs) with wire (WGEMs) or metal electrodes (MGEMs), which don’t use any plastic insulators between electrodes are created. The chambers containing MGEMs (WGEMs) with pin-anodes are proposed as detectors for searching of spin-dependent interactions between Dark Matter (DM) particles and gases with nonzero-spin nuclei (H2, D2, 3He, 21Ne, CF4, CH4, etc.). In this paper, we present a review of such chambers. For investigation of the gas mixtures Ne+10%H2, H2 (D2) +3ppmTMAE, the chamber containing WGEM with pin-anode detection system was constructed. In this paper we present the results of an experimental study of these gaseous mixtures exited by an α - source. Mixture of Ar + 40 ppm C2H4 and mixture 50% Xe + 50%CF4 have been investigated. The spatial distributions of photoelectron clouds produced by primary scintillations on α- and β-particle tracks, as well as the distributions of photoelectron clouds due to photons from avalanches at the pin-anode, have been measured for the first time. In our experiments as another filling of the chambers for search of low-mas WIMP (<10 GeV/c2), solar neutrino and solar axions with spin-dependent interaction we propose to use the mixtures: D2 + 3ppmTMAE, 3He + 3%CH4, 21Ne + 10%H2, at pressure 10-17 bar. And in our experiment with liquid gases is used the mixtures with 19F (LAr + CF4, LXe + CF4) and mixture LCH4 + 40ppm TMAE. The time projection chamber (TPC) with the mixture D2 + 3ppmTMAE filling allow to search of spin-dependent interactions of solar axions and deuterium. As well as we present the detecting systems for search of narrow pp-resonances (quarks) in accelerators experiments.

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