Logo-optiwave
Search
Close this search box.
Free Evaluation

spectral Direct detection problem in results

Home › Forums › SYSTEM › spectral Direct detection problem in results

Viewing 4 reply threads
  • Author
    Posts
    • May 11, 2014 at 1:17 pm #11434
      Eman
      Participant

      Each chip has a spectral width of 0.8 nm.the rates of 622 Mbps, and 1.25 Gbps for 10 km.At 1550 nm wavelength, the attenuation co-efficient was 0.25 dB/km, and the chromatic dispersion co-efficient was 18 ps/nm-km and the polarization mode dispersion (PMD) co-efficient was 5 ps/p km. The transmit power used was 0 dBm out of the broadband source.The dark current value was 5 nA and the thermal noise co-efficient was 1.8 *10-23 W/Hz for each of the photodetectors.

      These the parameters in system.

      I have a problem in results.

    • May 11, 2014 at 2:00 pm #11441
      Eman
      Participant

      this the paper

    • May 13, 2014 at 10:15 am #11467
      Damian Marek
      Participant

      Hey Eman,

      You will get a much better BER if you use a low pass filter on the output of the Photodetector PIN component. Use a cutoff frequency of 0.75*Bit rate to extract the signal.

      It is usually a better idea to change the Bit rate globally, by double-clicking anywhere on the layout or using the Project Browser in the bottom left corner. This will automatically update the bit sequence generators and also calculate a correct time window for visualizers etc. You will also notice that the low pass filters automatically have a cut-off frequency of 0.75*Bit rate.

    • May 13, 2014 at 8:11 pm #11499
      Eman
      Participant

      hi Damian Marek i made the changes you suggested but result still unreasonable
      take a look at it and tell me your suggestion
      thanks in advance

      • May 15, 2014 at 9:49 am #11551
        Damian Marek
        Participant

        The Low Pass Bessel Filters have a cut-off frequency of 0.75*Symbol rate. You should change that for the 0.75*Bit rate, which will cut out a lot more noise. I’m not exactly sure what your application is, but you might want to make sure you are using the gratings correctly in your design. If you are interested in some sort of WDM system, I would think you should use the reflected spectrum from your gratings and not the transmitted spectrum.

        Look at the spectrum response of fiber bragg gratings at this webpage:

        http://en.wikipedia.org/wiki/Fiber_Bragg_grating

        • May 16, 2014 at 8:45 pm #11681
          Eman
          Participant

          this is the project after modification please take a look at it and tell me if any additional modification can made

    • May 14, 2014 at 7:47 am #11504
      Roman Ibragimov
      Participant

      In my opinion, you can decrease lineweight of laser (for example get 0.01 MHz). Also, you need check all parameters in external modulator, maybe wrong bias voltage gets low BER.

  • Author
    Posts
Viewing 4 reply threads
  • You must be logged in to reply to this topic.

Contact us

1-866-576-6784

1-613-224-4700

info@optiwave.com

Learning

Community

Resources

© 2023 Optiwave Systems Inc.