Automatic alignment of photonic components of massive optical switch to ITU channels (Conference Presentation)

Author(s):  
Astghik Chalyan ◽  
Stefano Tondini ◽  
Giorgio Fontana ◽  
Lorenzo Pavesi ◽  
Nikola Zecevic ◽  
...  
Author(s):  
G.Y. Fan ◽  
O.L. Krivanek

Full alignment of a high resolution electron microscope (HREM) requires five parameters to be optimized: the illumination angle (beam tilt) x and y, defocus, and astigmatism magnitude and orientation. Because neither voltage nor current centering lead to the correct illumination angle, all the adjustments must be done on the basis of observing contrast changes in a recorded image. The full alignment can be carried out by a computer which is connected to a suitable image pick-up device and is able to control the microscope, sometimes with greater precision and speed than even a skilled operator can achieve. Two approaches to computer-controlled (automatic) alignment have been investigated. The first is based on measuring the dependence of the overall contrast in the image of a thin amorphous specimen on the relevant parameters, the other on measuring the image shift. Here we report on our progress in developing a new method, which makes use of the full information contained in a computed diffractogram.


2012 ◽  
Vol E95-B (3) ◽  
pp. 730-739 ◽  
Author(s):  
Kunitaka ASHIZAWA ◽  
Takehiro SATO ◽  
Kazumasa TOKUHASHI ◽  
Daisuke ISHII ◽  
Satoru OKAMOTO ◽  
...  

1988 ◽  
Vol 24 (15) ◽  
pp. 959 ◽  
Author(s):  
H. Okayama ◽  
A. Matoba ◽  
R. Shibuya ◽  
T. Ishida
Keyword(s):  

1988 ◽  
Vol 24 (6) ◽  
pp. 303 ◽  
Author(s):  
P.D. Colbourne ◽  
P.E. Jessop

1992 ◽  
Vol 28 (7) ◽  
pp. 638 ◽  
Author(s):  
H. Okayama ◽  
M. Kawahara
Keyword(s):  

1991 ◽  
Vol 27 (12) ◽  
pp. 1025 ◽  
Author(s):  
A. McGuire ◽  
M. Scott ◽  
A.P. Thomas ◽  
R.C. Booth
Keyword(s):  

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Sumit Chandra ◽  
Shahnaz Fatima ◽  
Raghuraj Singh Suryavanshi

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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