TWDM-PON

[FAYIQA NAQSHBANDI]

To reduce the frequency chirp introduced by directly modulated lasers..which of the availible filters in optiwave can be best used for optical spectral reshaping ?

[Aabid Baba]

hello fayiqa,
my first question is how do you calculate frequency chirp in optiwave?? you use which visualizer ?

Please refer to the link below:
http://onlinelibrary.wiley.com/doi/10.1002/mop.4650030108/abstract

[FAYIQA NAQSHBANDI]

Thank you so much.
well whenever we use direct modulated lasers it means frequency chirp is introduced. i am just asking for methods that can be used in optiwave to reduce the frequency chirp.

[Aabid Baba]

okay i got it.
Did you try externally modulated laser technique? It may prove to be less chirp introducing technique. In addition to that, the overall performance will be very good in externally modulated laser technique. I would suggest you to go for that technique and compare the results of the two techniques. Refer to the link provided below.
http://www.cpeu.dk/data/uploads/teaching/34129_e2009_cpeu_dml_eml.pdf

regards!

[Aabid Baba]

and yeah if you wish to you can use fiber bragg grating as a filter. i found it to be very effective in my project work. You may refer to the opyiwave samples to have an idea about fiber bragg grating. For theoretical knowledge about fiber bragg grating please refer to the other link ( these are basically MIT lecture notes on fiber bragg grating)
http://ocw.mit.edu/courses/mechanical-engineering/2-71-optics-spring-2009/video-lectures/lecture-16-gratings-amplitude-and-phase-sinusoidal-and-binary/

[aasif bashir dar]

i think there is no such filter in optisystem 14.

with regards.

[Aabid Baba]

Hello
i guess there would be some window for doing it. Infact in every system where we use direct modulated laser , frequency chirp gets introduced along dispersion which is common to all phenomena. We should mail at optiwave support care for further queries May be they have some knowledge regarding it.
Thank you for your considerations and responses.

[aasif bashir dar]

hi fayiqa,

have a look on these papers.
1.https://www.osapublishing.org/abstract.cfm?uri=OFC-1986-WBB5
2.http://digital-library.theiet.org/content/journals/10.1049/el_19850755
3.http://ieeexplore.ieee.org/xpl/abstractKeywords.jsp?reload=true&arnumber=4251592

you would get some idea of reduction of the chirping of external modulators

with regards

[Aabid Baba]

asif these paper don’t contain any substantial help. These focus on modulation schemes rather than on techniques required for reducing the frequency chirps. Any other suggestion which can be implemented in optiwave itself. I am using both techniques direct as well as external modulated laser schemes and unfortunately in both frequency chirp is introduced though less is in cooperated in external modulated laser.

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