2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahmoud M. A. Eid ◽  
Ahmed Nabih Zaki Rashed ◽  

AbstractThis study presents high speed optical switching gain based Erbium doped fiber amplifier model. By using the proposed model the optical fiber loss can be minimized. The system is stabilized with the power budget of 25.875 mW a long 75 km as a length of optical fiber in this study can be verified. The modulation rate of 10 Gb/s can be upgrade up to reach 30 Gb/s. The suitable power for the optical transmitter is −2.440 dBm and NRZ modulation code is verified. The receiver sensitivity can be upgraded with the minimum bit error rate and max Q factor are 1.806 e−009 and 5.899.


2021 ◽  
Vol 39 (9) ◽  
pp. 2762-2768
Author(s):  
Han Hyub Lee ◽  
KwangOk Kim ◽  
Kyeong-Hwan Doo ◽  
Jung-Yeol Oh ◽  
Gap-Yeol Moon ◽  
...  
Keyword(s):  

Author(s):  
Yih-Tun Tseng ◽  
Jhong-Bin Huang ◽  
Che-Hsin Lin ◽  
Chin-Lung Chen ◽  
Wood-Hi Cheng

The GI (graded-index) POFs (Plastic optical fibers), which has been proven to reach distances as long as 1 km at 1.25 Gb/s has a relatively low numerical aperture . Therefore, the efficient coupling of GI POFs to the light source has become critical to the power budget in the system. Efficient coupling for a POFs system normally involves either a separate lens or the direct formation of the lens at the end of the fiber. Forming the lens-like structure directly on the fiber end is preferred for simplicity of fabrication and packaging, such as polishing and fusion, combine different fibers with the cascaded fiber method and hydroflouride (HF) chemical etching. These approaches are well established, but applicable only to glass. Optical assembly architecture for multichannel fibers and optical devices is critical to optical fiber interconnections. Multichannel fiber-pigtail laser diode (LD) modules have potential for supporting higher data throughput and longer transmission distances. However, to be of practical use, these modules must be more precise. This work proposes and manufactures lensed plastic optical fibers (LPOF) array. This novel manipulation can be utilized to fabricate an aspherical lens on a fiber array after the UV curing of the photo-sensitive polymer; the coupling efficiency (CE) is increased and exceeds 47% between the LD array and the fiber array.


Author(s):  
PÅL HALVORSEN ◽  
TOM ANDERS DALSENG ◽  
CARSTEN GRIWODZ

Distributed multimedia streaming systems are increasingly popular due to technological advances, and numerous streaming services are available today. On servers or proxy caches, there is a huge scaling challenge in supporting thousands of concurrent users that request delivery of high-rate, time-dependent data like audio and video, because this requires transfers of large amounts of data through several sub-systems within a streaming node. Unnecessary copy operations in the data path can therefore contribute significantly to the resource consumption of streaming operations. Despite previous research, off-the-shelf operating systems have only limited support for data paths that have been optimized for streaming. Additionally, system call overhead has grown with newer operating systems editions, adding to the cost of data movement. Frequently, it is argued that these issues can be ignored because of the continuing growth of CPU speeds. However, such an argument fails to take problems of modern streaming systems into account. The dissipation of heat generated by disks and high-end CPUs is a major problem of data centers, which would be alleviated if less power-hungry CPUs could be used. The power budget of mobile devices, which are increasingly used for streaming as well, is tight, and reduced power consumption an important issue. In this paper, we prove that these operations consume a large amount of resources, and we therefore revisit the data movement problem and provide a comprehensive evaluation of possible streaming data I/O paths in the Linux 2.6 kernel. We have implemented and evaluated several enhanced mechanisms and show how to provide support for more efficient memory usage and reduction of user/kernel space switches for content download and streaming applications. In particular, we are able to reduce the CPU usage by approximately 27% compared to the best approach without kernel modifications, by removing copy operations and system calls for a streaming scenario in which RTP headers must be added to stored data for sequence numbers and timing.


Author(s):  
Devina Cristine Marubin ◽  
◽  
Sim Sy Yi ◽  

Can-Sized satellite (canSAT) is a small satellite that is used for educational purpose. CanSAT offer student to build their satellites with their creativity which make the learning process more effective. In Malaysia, SiswaSAT is held by the Malaysia Space Agency for students in different categories to participate and build their satellites according to rules set and it should be a low-cost project. CanSAT can be divided into few parts which are communication system, onboard data acquisition, ground control station and power system. The power system is one of the important and heaviest subsystems, it needed to supply power, but weight and size are one of the main concerned as the canSAT should not exceed the required weight and selecting power supply that is matched with the overall power budget that has small size and lightweight is challenging. Therefore, the power supply selection should consider this detail. The power distribution design should be able to supply an appropriate amount of current and voltage to the components according to their specification. This study aims to develop and test the proposed prototype which is named ScoreSAT able to provide data and have enough power supply for the whole operation. Therefore, an initiative to develop the appropriate power distribution design for canSAT is taken to overcome the problem of the power system. Moreover, each subsystem needs to be tested by obtaining the results from the onboard data acquisition and transmit the data using the communication system before integrating into the power system. ScoreSAT prototype needs to carry the system that is mounted inside, thus the space inside the prototype needs to be fully utilized for the whole system to fit in. ScoreSAT completes the mission by obtaining data acquisition during the operation.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rupinder Kaur ◽  
Charanjit Singh ◽  
Rajbir Kaur

Abstract Hybrid wavelength-division-multiplexing (WDM) and free space optical (FSO) access networks are getting great attention due to numerous advantages. In this work, hybrid WDM-FSO system is demonstrated for 55 km at capacity of 5 × 10 Gbit/s using compressed spectrum return to zero (CSRZ) WDM-FSO in downstream and nonreturn to zero (NRZ) in upstream for demonstrating transmitter diversity which inturn decrease the interchannel interference. For the suppression of Rayleigh backscattering (RB) interferometric beat noise, bidirectional cyclic multiplexer is employed. Cyclic multiplexer provide λ 1 to λ 5 wavelengths for optical line terminal (OLT) to ONU transmission and λ 2 to λ 6 for ONU to OLT transmission. Insertion losses of each component are considered and in the end, power budget is also calculated. Results revealed that FSO length of 780–1050 m are obtained using various WDM-FSO downstream signals and their power budget, redundant budget, maximum distance, and insertion losses also calculated.


2017 ◽  
Vol 36 ◽  
pp. 255-264 ◽  
Author(s):  
Ricardo O.J. Soeiro ◽  
Tiago M.F. Alves ◽  
Adolfo V.T. Cartaxo

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