Search Results for 'wdm'

[Karan AhujaSpectator]

Hi Rajguru
As we know studies have been carried out on NG-PON2 enabling technologies, such as 40 G TDM-PON,wavelength division multiplexed PON (WDM-PON), time and wavelength division multiplexed PON (TWDM-PON) and orthogonal frequency division multiplexing PON(OFDM-PON).
And among all these technologies, TWDM-PON has beenselected as the best candidate for NG-PON2 because itsupports backward compatibility, flexibility and static sharing.
At the OLT side, a set of laser diodes such as distributedfeedback (DFB) laser diodes operating at different wave-lengths serve as downstream laser sources, followed by aWDM for multiplexing.
Therefore, ONU must contain tunable trans-mitters and receivers devices. A tunable filter at thereceiver is used to select or tune to any of the fourdownstream wavelengths. In case of upstream wave-lengths, the tunable laser is used to provide colorlessONU (free operation wavelength) to enable easier networklaying and maintenance.

Regards

[gulkaran bajwaParticipant]

Hello rajguru,

In TWDM scheme based PON TDM is used for uplink in which different user of ONU can send their data with same wavelength.
i think you are messing with Dynamic Y select there are some important parameter you should concern first
The formula for the Dynamic Y Select 1 for x time slots is given by default
Switching Time event is depend upon X= how many users you are using on same wavelength
For example in BPON example given by Optisystem where X=8 because they are using 8 ONUs which uses same wavelength
So in a default formulate change the value of X might be that will be helpful to you because i was facing same problem before.

[Karan AhujaSpectator]

i am providing you with a link of another paper which introduces an “ultra-dense” concept into next-generation WDM-PON systems, which transmits a Nyquist-WDM uplink with centralized uplink optical carriers and digital coherent detection for the future access network requiring both high capacity and high spectral efficiency. 80-km standard single mode fiber (SSMF) transmission of Nyquist-WDM signal with 13 coherent 25-GHz spaced wavelength shaped optical carriers individually carrying 100-Gbit/s polarization-multiplexing quadrature phase-shift keying (PM-QPSK) upstream data has been experimentally demonstrated with negligible transmission penalty. The 13 frequency-locked wavelengths with a uniform optical power level of -10 dBm and OSNR of more than 50 dB are generated from a single lightwave via a multi-carrier generator consists of an optical phase modulator (PM), a Mach-Zehnder modulator (MZM), and a WSS. Following spacing the carriers at the baud rate, sub-carriers are individually spectral shaped to form Nyquist-WDM. The Nyquist-WDM channels have less than 1-dB crosstalk penalty of optical signal-to-noise ratio (OSNR) at 2 × 10(-3) bit-error rate (BER). Performance of a traditional coherent optical OFDM scheme and its restrictions on symbol synchronization and power difference are also experimentally compared and studied.
Here is the link of the paper. Hope this is helpful
http://www.ncbi.nlm.nih.gov/pubmed/21716338

[Karan AhujaSpectator]

i want to also mention that to meet growing demands for bandwidth, a technology called Dense Wavelength Division Multiplexing (DWDM)
has been developed that multiplies the capacity of a single fiber. DWDM systems being deployed today can increase a single fiber’s capacity sixteen fold, to a throughput of 40 Gb/s! Which is still not enough to manage the current bandwidth requirements of the corporate, which is up to 1Tb/s? So in this paper we are going to discuss how this enormously high bandwidth and speed could be achieved. This cutting edge technology—when combined with network management systems and add-drop multiplexers— enables carriers to adopt optically-based transmission networks that will meet the next generation of bandwidth demand at a significantly lower cost than installing new fiber.The potential bandwidth of single mode fiber is 50 Tb/s, so we are going to demonstrate how to achieve less than 1/10th of this enormous speed which is still quite a lot taking into consideration today’s scenario. We are going to show the techniques to achieve the high bandwidth of 1 Tb/s.
regards

[Karan AhujaSpectator]

hi ranjeet
i am attaching a link which can be very helpful to you. It is a paper which should help you in getting some idea.
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=6013167&abstractAccess=no&userType=inst
In this paper a new structure of PON system based on coherent heterodyne receivers is presented. The coherent detection enables a filterless ultra-dense WDM system. here they have simulated a 64 channel system with 10GHz channel spacing, offering symmetrical 1 Gbit/s sustained data rate per user both downlink and uplink by single fiber. The quadrature phase-shift keying (QPSK) modulation format is applied to downstream data for higher spectrum efficiency, while use of Amplitude Modulation (AM) on upstream data to reduce the system cost. Hope it helps you.
Regards

[Rajguru M. MohanParticipant]

Hi Hamza Ali Abbas Khan,
I agree to your points that there are three basic types of PON as APON, BPON and GPON.
The use of ATM-based PON (APON and BPON), the achieved upstream and downstream aggregate bandwidths were in the order of
155 Mbit/s up to 622 Mbit/s. Later, the use of time division multiplexing (TDM) permitted
achieving capacities around 1.2 Gbit/s and 2.5 Gbit/s (downstream & upstream) according with
the ITU-T G.984 G-PON standard. Advanced high-speed TDM based optical access systems
up to 10Gbit/s for downstream and 2.5 upstream (XG-PON1) or 10Gbit/s/ for both downstream
and upstream (XG-PON2), according with the ITU-T G.987 G-PON standard, have been
developed and some field trials have been reported. Currently, standardized specifications by
ITU exist for ATM-based PON (APON and BPON), gigabit-capable PON (GPON) and XG-PON
and Ethernet PON (EPON) and 10G-EPON by IEEE.

For several years FSAN and IEEE have been working on the new international standard ITU-T
G.989: 40-Gigabit-capable passive optical networks (NG-PON2) which general requirements
have been defined on ITU-T G989.1 standard by March of 2013. However the PMD (ITU-T
G989.2) and TC layer requirements (ITU-T G989.3) are still being discussed and are expected
to be published soon.

Further research are going towards Next Generation PON: NGPON1 and NGPON2.
Hybrid TDM and WDM PON are latest type of PON recommended by ITU-T.
Thanks,

[Rajguru M. MohanParticipant]

Hi Ranjeet,
Meanwhile, companies such as Wave-Splitter Technologies are pursuing the development of 25-GHz channel demultiplexing using arrayed-waveguide-grating routing technology and interleavers. Interleaving is frequently used in 50-GHz channel spacing. Basically, one set of 100-GHz-spaced channels or wavelengths is going in one direction and another set of wavelengths is going in the opposite direction.
The fiber Bragg grating technology that supports 25-GHz and 12.5-GHz channel spacing will allow carriers to increase the number of channels in the C-band without requiring other major component upgrades in the network, such as additional amplifiers, according to Ciena. The same technology could also be used in the L-band and S-band.

i would suggest you to please refer to following links:
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=6013167&abstractAccess=no&userType=inst
http://www.ijarcsse.com/docs/papers/Volume_4/6_June2014/V4I6-0319.pdf
http://www.fiberoptic.com/adt_dwdm.html
http://www.ncbi.nlm.nih.gov/pubmed/21716338
https://www1.doshisha.ac.jp/~toda/Publications/2-37.pdf
http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1158853
http://www.cisco.com/c/en/us/td/docs/optical/15000r7_0/dwdm/planning/guide/70epg/d7ovw.html

thanks,

[Rajguru M. MohanParticipant]

Hi,
I am trying to compare between NRZ and RZ modulation formats.
Practically, it has been demonstrated numerically and experimentally that the conventional
nonreturn-to-zero (NRZ) modulation format is superior compared to the return-to-zero (RZ) modulation
when dealing with large WDM systems, as RZ modulation causes a significant Eye Closure Penalty near end channels.
The results obtained in this tutorial will be used to compare the Eye Closure Penalties for both NRZ and RZ cases,
as well as the effects of nonlinearities.
The advantage of RZ format in terms of transmission
distances was recently demonstrated in a long-distance wavelength
division multiplexing (WDM) transmission experiment though most WDM transmission experiments conducted
so far have used NRZ formats [6]. WDM signals, which were
initially NRZ but modified before transmission, were successfully
transmitted over transoceanic distances in a recirculating
loop. Time-division multiplexing (TDM) transmission experiments
, of course, use RZ signal formats, which allow
optical MUX-DEMUX to be easily carried out. The relative
advantages of NRZ or RZ formats are, however, still unclear
even in single-channel long-distance transmission.

Thanks,

[Rajguru M. MohanParticipant]

Hi Md. Asraful Sekh,
i agree to the points of Damian Marek sir that simulation of Multiple OWC channels can be done by splitting a modulated signal into several branches (power splitter) and attaching each branch to an OWC.
I want to share some links:
http://www.hindawi.com/journals/ijo/2015/945483/
https://www.researchgate.net/publication/273917945_Hybrid_WDMmultibeam_free-space_optics_for_multigigabit_access_network
http://www2.engr.arizona.edu/~vasiclab/files/papers/ANV_06_WDD.pdf

Thanks,

[umer ashraf waniParticipant]

https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwiI5cqnkMPMAhXCm5QKHdqBCxsQFggwMAI&url=http%3A%2F%2Farxiv.org%2Fpdf%2F1506.04836&usg=AFQjCNHOwt-SFI4K_Yb7Am2MUMhGFeDGGA&sig2=Pok6isJaV5AToLwoyzVT8A
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&cad=rja&uact=8&ved=0ahUKEwiI5cqnkMPMAhXCm5QKHdqBCxsQFghWMAc&url=https%3A%2F%2Fwww.osapublishing.org%2Fabstract.cfm%3Furi%3Dao-46-26-6561&usg=AFQjCNFqZsEjTaEMeWOjxcM4-3P0H3zf8g&sig2=3lr-s9yF-qg6W3e8Q0fRrw
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=12&cad=rja&uact=8&ved=0ahUKEwi1p7a8kMPMAhWIGpQKHZEoBCc4ChAWCBwwAQ&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D7002326&usg=AFQjCNHjY5LTZCBRzMEOQRag0_G5sU0ZxQ&sig2=zCie6BBXUUylyd7IBwp0Aw&bvm=bv.121421273,d.dGo
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=17&cad=rja&uact=8&ved=0ahUKEwi1p7a8kMPMAhWIGpQKHZEoBCc4ChAWCD8wBg&url=https%3A%2F%2Fwww.researchgate.net%2Fpublication%2F273917945_Hybrid_WDMmultibeam_free-space_optics_for_multigigabit_access_network&usg=AFQjCNGiU_y8Pw4CkWywa2H3qsOXrwysEA&sig2=ejasUYZSTBkozuFFTzhHEQ&bvm=bv.121421273,d.dGo
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=33&cad=rja&uact=8&ved=0ahUKEwjA2uHJkMPMAhWJQpQKHXk3DvU4FBAWCEcwDA&url=http%3A%2F%2Fdigitalcommons.calpoly.edu%2Fcgi%2Fviewcontent.cgi%3Farticle%3D1020%26context%3Deeng_fac&usg=AFQjCNGjcMyyncCjQtiul8GDbNn_sVUpzQ&sig2=PHyEUn9ZPnwLWId9DXV7-Q&bvm=bv.121421273,d.dGo

https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=37&cad=rja&uact=8&ved=0ahUKEwjd9o7SkMPMAhXEHZQKHcNNCdY4HhAWCEIwBg&url=https%3A%2F%2Fpdfs.semanticscholar.org%2F71a7%2Fe5511ef11fbc3f815722e8d73dfb65f10618.pdf&usg=AFQjCNGeI90harSvPRBBrFFXrPmbu0xGyw&sig2=0To-3J5Y0UFZppQpwcfXiA&bvm=bv.121421273,d.dGo

[umer ashraf waniParticipant]

https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwjymJCRi8PMAhXFHJQKHfdNDnAQFgglMAE&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D6801268&usg=AFQjCNFAbpVX0oUvVyw9bOFmDZ8yx0omfg&sig2=InERleMyLuDOp2s_Hpg_kA
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&uact=8&ved=0ahUKEwjymJCRi8PMAhXFHJQKHfdNDnAQFghIMAY&url=https%3A%2F%2Fwww.osapublishing.org%2Fviewmedia.cfm%3Furi%3DOECC_PS-2013-PD3_6%26seq%3D0&usg=AFQjCNGIX3Ns3pBQLN9bhJaMSPzBgEOsuw&sig2=FqEeo7jQTfAOoGMPweK8aw
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact=8&ved=0ahUKEwjymJCRi8PMAhXFHJQKHfdNDnAQFghZMAg&url=http%3A%2F%2Fnanophotonics.ece.cornell.edu%2Fupload%2FarXiv1306_2378.pdf&usg=AFQjCNEY3OAJYFC26TBJqcHMek6ZCdZymQ&sig2=aenhVUrF8WXdF9HhQV2wrw
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&cad=rja&uact=8&ved=0ahUKEwj2y6Cwi8PMAhXKGJQKHa6RAhM4ChAWCBowAA&url=http%3A%2F%2Flightwave.ee.columbia.edu%2Ffiles%2FLuo2014a.pdf&usg=AFQjCNEpbMD5vvuCtLMkrHwmN723sfE-Lg&sig2=otDv8d2jRvazJSwgIBRj4g&bvm=bv.121421273,d.dGo
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=22&cad=rja&uact=8&ved=0ahUKEwjb8Jm6i8PMAhVEG5QKHY4tBqo4FBAWCCIwAQ&url=http%3A%2F%2Fwww.lightreading.com%2Fmode-gap-talks-mdm-wdm%2Fd%2Fd-id%2F698474&usg=AFQjCNHWfoZxYE_QJ4QLp3ffckSAJ8T8AQ&sig2=GDbwQs3v_GzYlWXj7gRTtQ&bvm=bv.121421273,d.dGo

[Rajguru M. MohanParticipant]

Hi Mahmoud Ghorbel,
You can use wdm system of 8 channel with global rate of 20 gbps using different advanced modulation formats like CSRZ, DRZ, MDRZ or DPSK.
You should use dispersion compensation techniques like pre, post and symmetrical.
You could change fiber length by using no. of loops.

here i am uploading a osd file of csrz wdm system

[Rajguru M. MohanParticipant]

Hi,
I agree to Damian Marek sir that spatial information with more than one modes carrying information will support WDM system

thanks,

[Rajguru M. Mohan]

Hi everyone,
Would someone suggest me how to design bidirectional TWDM PON.
When i use buffer selector in the receiver part , actually it continuously simulating Buffer selector and never gets simulated.
Would you suggest me how could i get my problem resolved?.
Thank you.

[Rajguru M. MohanParticipant]

Hi,
I would suggest you to pease refer to following links:
https://www.itu.int/rec/T-REC-G.694.1/en
http://www.chronos.co.uk/files/pdfs/itsf/2008/Day1/Standards_Update_ITU_(Jean-Loup_Ferrant,_Alcatel-Lucent).pdf
http://www.cisco.com/c/en/us/td/docs/optical/15000r7_0/dwdm/planning/guide/70epg/d7ovw.html
https://www.itu.int/rec/T-REC-G.9955
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6094004