Search Results for 'wdm'

[love kumarParticipant]

hi Rajguru … sending you a paper on TWDM 4 channel system ..i guess it will be beneficial to you..please find the attachment ….. if facing any problem in downloading .. send me a test mail on er.lovekumar@gmail.com

[Rajguru M. MohanParticipant]

Hi Tanveer,
Please refer to sample files of optisystem for wdm ring network namely WDM ring.
AS wdm netwotk ic active optical netwotk(AON).
Also for The metro-ring network we modeled operates with 2 wavelength carriers in which
several subscribers share the bandwidth. For illustration purposes,
the network contains one Network Node (NN) and one Access Node (AN).
It support: cost-shared virtual rings (the distribution ring network connected to AN,
single wavelength goes around this sub-rings)
By using a packet format, multiple users can share a single wavelength.,go through
following link:

WDM Ring – Wavelength Independent Subscriber Equipment

Thanks

[Rajguru M. MohanParticipant]

Hi Ankita,
We have lots of benefits of tunable laser. They are as:
As tunable lasers are classified into three structural types: an external cavity laser,
a distributed feedback (DFB) laser array, and a distributed Bragg reflector (DBR) laser.
All of these laser structures provide a tuning range of more than 35 nm, which is required for DWDM systems.
Another important aspect of the tunable lasers
performance, when switching between wavelengths, is
the wavelength stability of the device. As the laser tunes
into its desired wavelength, there is a settling drift before
the channel finally stabilizes. This drift can have a large
impact on the performance of a dense wavelength
division multiplexed system (causing adjacent channel
interference) and therefore must be fully characterized, in
terms of both the magnitude of the drift and the time it
takes to settle to the destination wavelength.
The external cavity laser which can an easily provide a wide tuning range because optimum optical filters can be selected.
This laser is a strong light source for digital coherent systems.
Its drawbacks are that complex tuning control is needed to suppress mode hopping and that it has many optical parts.

Thanks

[Rajguru M. MohanParticipant]

In addition to above points i would like to suggest links regarding DWDM +ROF system.
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5689024&abstractAccess=no&userType=inst
http://www.inase.org/library/2014/interlaken/bypaper/COSICO/COSICO-30.pdf
http://www.ijettjournal.org/volume-17/number-10/IJETT-V17P292.pdf
http://ieeexplore.ieee.org/Xplore/defdeny.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D6210761%26userType%3Dinst&denyReason=-133&arnumber=6210761&productsMatched=null&userType=inst
You have talked about ROF without OADM, it means you are using WDM mux and demux.
Here i am uploading the osd file of 8 channel wdm system with 100 ghz channel spacing and using symmetrical compensation with CSRZ modulation formats for your reference.

[Rajguru M. MohanParticipant]

Hi Gede Teguh,
So, you have already said that you are trying to increase the bit rate and you are finding difficulties.
I suggest you to use advanced modulation formats like CSRZ, DRZ and MDRZ and DPSk because these supports both long haul transmission and high data rate.
As we know that The use of Dense Wavelength Division Multiplexing
WDM system is responding to the demands for high
data rate applications and reasonable mobility for broadband communication.
It is easy to see that the dispersion become
the major factor that restricts long distance fiberoptical
transfers as the bit rate increases . so, you must use dispersion compensation techniques to mitigate dispersion.
You should use Pre, post or symmetrical dispersion compensation techniques to achieve above goals.
dispersion
compensation is achieved with DCF using postcompensation.
Post -compensation scheme achieve
dispersion compensation by place the DCF after a
certain conventional single-mode fiber.. EDFA is
used to compensate the power loss generating by
SMF and the DCF signal. Three EDFAs are used in
the system as a power amplifier, inline amplifier and
preamplifier.

Hope it will works for you.

[Rajguru M. MohanParticipant]

Hi Manoj,
A good quality transmission with WDM systems goes with larger channel spacing, to be careful to
not excessively increase to avoid nonlinear effects and There is a logical increase of the quality factor.
we increase the channel spacing more the link quality get better and the
BER decreases.
Conventional WDM and DWDM uses increased channel spacing to allow less sophisticated and thus cheaper transceiver designs.
The small channel spacing allows to transmit simultaneously much more information.
The channel spacing, in GHz, relates to the optical wavelength as follows: A spacing of 200 GHz corresponds to about 1.6 nm, 100 GHz corresponds to about 0.8 nm, and 50 GHz corresponds to about 0.4 nm channels spacing. Most commonly 50 GHz follows 100 GHz, although attempts at 75 GHz and 37.5 GHz show up in literature. While there is nothing magical about any of these numbers, it seems likely that 50 GHz will be the next logical step below 100 GHz. Using a channel spacing of 50 GHz (0.4 nm) allows 45 channels to occupy only 17.5 nm of optical bandwidth. This greatly simplifies the requirement for optical amplifiers in the system. Fiber increases in channels per fiber would likely lead to the use of 25 GHz spacing. Designing the optical demultiplexer to separate the signals at the receive end defines the greatest challenge in closely spaced optical channels.

Regards,
Rajguru

[Rajguru M. MohanParticipant]

Hi all,
Thank you all for sharing and posting your links and your comments.
It is really helpful and important information about soliton-transmission-in-fiber-optics.
As far I know about soliton transmission and its advantage as :
1. Because of the unique features of optical solitons, soliton transmission can help to solve other problems of data transmission, like polarization mode dispersion.
2. Also, when used with frequency guiding filters (sliding guiding filters in particular), the soliton systems provide continuous all-optical regeneration of the signal suppressing the detrimental effects of the noise
3. Reduces the penalties associated with wavelength-division multiplexed (WDM) transmission.
4. Because the soliton data looks essentially the same at different distances along the transmission, the soliton type of transmission is especially attractive for all-optical data networking.
5. Moreover, because of the high quality of the pulses and return-to-zero (RZ) nature of the data, the soliton data is suitable for all-optical processing.

Please comment on above advantages of soliton transmission. are you agree with it not.

Thanks and regards,
Rajguru

[Rajguru M. Mohan]

Hi Everyone,
I want to know about Soliton Transmission in Fiber Optics in optical fiber communication.
What we exactly mean to Soliton Transmission.
How could i implement Soliton Transmission using optisystem.
Because it is future trends in OFC, so we needs to know about it.
As tThe application of solitons in communication systems opens the way to ultrahigh-speed information superhighways. Transmission speed of order of Tbit/s can be achieved if optical amplifiers are combined with WDM in soliton based communication systems.
The simulation results for Soliton order N=1 and N=3 are obtained using OptSim Software.
Could it possible to implement in optisystem software.

Hope you will take interest in this topic.

[Rajguru M. MohanParticipant]

Hi ankita,
Please suggest some links or instructions for implememtation TWDM system.

Regards,
Rajguru

[Rajguru M. MohanParticipant]

Hi Nagesh,
As i have discussed that i want to basic TWDM system like 4 users.
I have asked for osd file of TWDM system.
If possible, at least share instructions to design TWDM system properly, this may be in the form of image or pdf or links.

If you know how to implement tunable lasers for improving system performance and externally modulated lasers in optisystem.
Also share this.
Regards,
Rajguru.

[Rajguru M. MohanParticipant]

Hi,
I know some of basic parameters, technologies and requirements related to it like:
Tunable transmitters comprises of
Distributed feedback (DFB) laser with temperature control (TC),
External cavity laser (ECL) with mechanical control without cooling,
Tunable receivers with following :Liquid-crystal tunable filter,
Thermally-tuned Fabry-Perot (FP) filter
The prototype of TWDM employs the C-band wavelength plan to achieve coexistence
with the previous generations of PON, while the four downstream wavelengths are spaced 200GHz apart.

So, please share some advanced and necessary elements related to it.
Thanks and Regards,
Rajguru

[Rajguru M. Mohan]

Hi everyone,
On April 2012,after the meeting of the Full Service Access Network (FSAN) group,
time and wavelength division multiplexed passive optical network (TWDM-PON) technology
was chosen as the primary solution for next-generation passive optical network stage-2 (NG-PON2) architecture,
the evolving specifications are wavelength plans, loss budgets, and key technologies that enable tunable ONUs.

So, i want to work on time and wavelength division multiplexed PON.
I have tried to design TWDM-PON in optisystem , but didn’t get results.
I request you all to please , if possible to Upload the osd file of TWDM-PON.
So, that i could enhance the system.
You could even share some important links related to it.

Seeking your response.

[Rajguru M. MohanParticipant]

Hi Fady,
I am uploading osd file of bidirectional WDM-OFDM PON networks,
This will help you to design various OFDM PON networks.
I am also uploading osd file of unidirectional WDM-OFDM PON networks of 4 user.
I have used OS12 ofdm modulator in the design.
OS12 doesnot have pilot and training ports.

Hope this will help you.
Regards,
Rajguru

[Rajguru M. MohanParticipant]

Hello Hermawan Widiyanto,
Usually when we increase the input power of laser, our system performance will enhance.
But after a certain optimum value the system performance will remains the same.
In most of the cases of WDM system we varies the laser power in the range of -5dbm to 5dbm.
So, you should also check for the application of laser to decide the range of power input.
I think it also varies for different applications.

seeking your response.

[Rajguru M. MohanParticipant]

Hi Jyoti,
We could measure OSNR with the help of BER of BER analyzer,
The formula for calculating OSNR from BER is :
We can also use WDM analyzer to check the OSNR.
Given the OSNR, the empirical formula to calculate BER for single fiber is

Log10 (BER) = 10.7-1.45 (OSNR)
For Example:
Assume that OSNR = 20.5 dB
Then Log10 (BER) = 10.7-1.45 (20.5) = -19.025
Therefore BER = 10^(-19.025)
BER is approx 10^-19
I think it is appropriate way to calculate BER from OSNR

Hope this will help you.