Optical subcarrier-multiplexing for output-port contention resolution

2000 ◽  
Vol 12 (11) ◽  
pp. 1567-1569 ◽  
Author(s):  
O.H. Adamczyk ◽  
S.A. Havstad ◽  
A.B. Sahin ◽  
M.C. Cardakli ◽  
S. Lee ◽  
...  
Keyword(s):  
Output Port ◽  
Contention Resolution ◽  
Subcarrier Multiplexing

A UHF Compact Complex Impedance-transforming Balun with High Isolation

2020 ◽  
Vol 13 (8) ◽  
pp. 1135-1144
Author(s):  
Kittipong Nithiporndecha ◽  
Chatrpol Pakasiri
Keyword(s):  
Complex Impedance ◽  
Output Port ◽  
Reflection Coefficients ◽  
Coupled Line ◽  
High Isolation ◽  
Line Structure ◽  
Source Impedance ◽  
Phase Balance ◽  
High Output

Background: A compact complex impedance-transforming balun for UHF frequencies, which is based on a coupled-line structure that matched all ports and provided high output port isolation, was designed in this paper. Methods: A lumped component transformation was used to minimize circuit size. The implemented circuit operated at 433 MHz with the reflection coefficients less than -16 dB at all ports, 0.22 dB amplitude balance and 180° phase balance at the output ports. The signal coupling between the output ports was -16.8 dB. The circuit size is small at 0.032λ. Results: Complex impedance-transforming baluns were designed to operate at 433 MHz. The source impedance at port 1 was set at Zs = 12 - j12Ω and the load impedances at port 2 and 3 were set at ZL = 80 + j30Ω. Conclusion: A compact complex impedance-transforming balun at UHF frequency, with all ports matched and high isolations, was designed and illustrated in this paper.

Hybrid buffer‐based optical packet switch with negative acknowledgment for multilevel data centers

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Sumit Chandra ◽  
Shahnaz Fatima ◽  
Raghuraj Singh Suryavanshi
Keyword(s):  
Data Centers ◽  
Web Applications ◽  
Optical Switch ◽  
Contention Resolution ◽  
Multilevel Data ◽  
All Optical ◽  
Optical Buffering ◽  
Different Types ◽  
Packet Switch ◽  
Novel Design

AbstractIn the present scenario, data centers serve many functionalities like storage, transfer of data, supporting web applications, etc. In data centers, various levels of hierarchy different types of switches are required; therefore, multifunctional data centers are desired. This paper discusses a novel design for optical switch which can be placed at various levels of hierarchy. In the proposed design, multifunctionality contention resolution schemes which consider electronic and optical buffering and all-optical negative acknowledgment (AO-NACK) are considered. In buffering technologies, contending packets are stored in either in electronic RAM or in fiber delay lines. In case of the AO-NACK scheme, contending packets are blocked, and a negative acknowledgment is sent back to the transmitting node and blocked packets are retransmitted. For various considered schemes, Monte Carlo simulation have been performed, results in terms of packet loss probability are presented, and it has been found that the performance of optical buffering is much superior to electronic buffering and AO-NACK schemes. It is found that, in the AO-NACK scheme, the numbers of retransmitted packets due to contention blocking are 33,304 which can be reduced to 7, by using a small amount of buffer at each node.

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