Search Results for 'DPSK'

[Karan AhujaSpectator]

Hello,
I want to mention that in conventional DQPSK receivers a pair of onebit delay asymmetric Mach-Zehnder interferometers (AMZI) are used: one for the in-phase (I), and one for the quadrature (Q) component. Similar to binary DPSK3, a narrow optical filter can be used instead of each AMZI 4. The frequency response the optical filters should approximate the main lobe of the frequency response of the constructive port of the AMZI. By tuning the central frequency of the filter either the I or Q component of the DQPSK signal can be demodulated. We will call such a receiver a narrow filter (NF) receiver. We experimentally demonstrate in this paper that a single arrayed waveguide grating (AWG) can be used
to simultaneously demodulate the in-phase (or quadrature) component of a comb of DQPSK signals. It can be seen how the AWG filter approximates the main lobe of the theoretical response of the AMZI. The use of AWGs for WDMDQPSK signals represents a big advantage in terms of component counts.
Hope this helps.
regards

[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

Attachments:

1. 8channelCSRZ.osd

[Rajguru M. MohanParticipant]

Hi,
For 100 gbps over 500 km , i suggest you to use DPSK modulation formats.
You could use 8 channels with data rate 12.5 Gb/s(12.5*8= 100 Gb/s) or 4*25 gbps.
You should use dispersion compensation techniques.

[Leeba Babu]

I need RZ-dpsk signals as input in my system. Can anyone help me out to generate DPSK signals in optisystem ? How to generate them ?

[Rajguru M. MohanParticipant]

Hi Naazira,
Moreover, A dynamic threshold data receiver uses a single comparator for both squelch and data detection.
It has various advatege over static threshold like:
The comparator has a high-magnitude threshold when the receiver is squelched and a low-magnitude threshold when the receiver is unsquelched.
Preferably the comparator is a differential line receiver, and each of the high and low magnitude thresholds has hysteresis.
he switching threshold is automatically adjusted in response to varying operation conditions such as changes in the received optical signal power. Nonlinear optical thresholding or decision thresholding are used to improve the system
performance and suppress the multiple access interferences in asynchronous
system. Using an encoding/decoding (E/D) technique and
optical thresholding multiple access interference (MAI) can be eliminated
effectively. In on-off keying (OOK) OCDMA, the interference level is
studied to be more and also requires high power level to maintain the desired
BER for the given number of users with direct detection. Even after
employing the optimum fixed decision threshold or adoptively varying the
decision threshold with the number of users, the performance of the
8
asynchronous OOK OCDMA system does not meet performance level of
differential phase shift keying (DPSK) OCDMA. Optical thresholding in
OOK OCDMA can eliminate MAI to the extent as that of DPSK
encoder/decoder in the system without sacrificing the BER and OSNR
required for proper operation of the receiver.

Thanks,

[Rajguru M. MohanParticipant]

Hi Fadil Paloi,
First of all i suggest you to use symmetrical no. of channels like- 2,
4, 8, 16, 32, 64 and so on.
Because in all the design i have seen suggest to use symmetrical
number of channels.
As we also know that non-linearities effects increases as data rate increases.
Also dispersion and other losses increases.
So, lowering of q-factor and increament of BER is expected to occur.

I suggest you to use some advanced modulation formats like csrz, drz, mdrz and dpsk,
because it supports high data rate and long haul transmission.

Here i am uploading 32 channel CSRZ wdm system at data rate of 40 gbps.
Also use dispersion compensation techniques namely pre, post or symmetrical.
According to me i symmetrical dispersion compensation techniques is best of all three.

Attachments:

1. 32CSRZchannel100ghz-mux-demux-symmetrical.osd

[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.

[shafeen al yasin]

Hello Everyone,

First of All thank you all for responding so well to my previous query.

Actually i want to plot a Spectral efficiency vs Signal to Noise Ratio (SNR) curve for different advanced modulation schemes such as BPSK, DPSK, QPSK, QAM, MSK, M-Ary etc.
Is there any provision to directly plot the curves of all the modulation schemes mentioned above.?

Thanks
Regards
Shafeen

[faiz iqbal]

hello everyone
I want to dpsk demodulator. but it is not avaliable in optisystem. Please tell me the alternative.
thanx

[Ranjeet Kumar]

Hi Everyone,
I want to design Ultra Dense Wavelength Division Multiplexing System using different advanced modulation formats like CSRZ, DRZ, MDRZ and DPSK and DQPSK.
My aim to design above system with channel spacing 50GHZ and 25GHZ.
I have design the above networks for 100GHZ channel spacing using symmetrical compensation technique and at a bit rate of 40gbps and for long haul communication i.e upto 1200 Km.
Here i am uploading 32 channel WDM system with 100ghz channel spacing system at 40 gbps bit rate and using symmetrical compensation technique. But when i decease the channel spacing upto 50ghz and 25 ghz, we doesn’t find results at BER analyzer, although it works for channel spacing of 75ghz.
So, I request you to suggest some techniques or steps to get it.
Here I am uploading an osd file of 100 ghz channel spacing CSRZ DWDM system.

Seeking your response.

Attachments:

1. 8channelCSRZ.osd

[varinder singhParticipant]

hello..
i think qpsk can be used as dpsk …so that you can convert into dqpsk..qpsk only transfer two bits and dpsk transfer only one bit…so you can convert simply into dqpsk..
with regards

[Urvi pathakParticipant]

hi
Thanks for replying.I have already implemented DPSK with 4 channel it works perfectly but DQPSK with 4 channel is not working here i am attaching the firl for reference.Please see it.

Attachments:

1. DQPSK-WDM-4.osd

[Ranjeet KumarParticipant]

Hi Urvi,
due to bad internet connectivity i was unable to upload the osd file of 7 user wdm system with DPSk modulation schemes,
Which i was discussing above.
Now i am uploading that osd file of DPSK
Hope this may help you.

Attachments:

1. DPSK-7Channels_Script1.osd

[Ranjeet KumarParticipant]

Hi Urvi,
I am attaching you an osd file of 7 user wdm system with DPSk modulation schemes.

[Lukas KoritarParticipant]

Hello Aabid,
I was trying this example (https://optiwave.com/resources/applications-resources/optical-system-digital-modulation-dpsk/) according files which you’ve attached (DPSK Step xx) and if I run the project, the output behind DPSK sequence decoder is zero (I made screen, I’ve attached screen below). Maybe the same error will be in my 32QAM project that output behind decoder is all zero.
Regards

Attachments:

1. 

   output.png