Single Polarization CO-OFDM Fiber Optic Communication Systems

OCSim Modules

Modern Fiber Optic Communication Systems Simulations with Advanced Level Matlab Modules

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Module 9b

 

Channel Multiplexing Techniques

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Single Polarization CO-OFDM Fiber Optic Communication Systems


Company Researchers & Developers

Integrate the Modules with your in-house and Commercial Software & Hardware Products

 

(1) Use the Existing Modules / Components for Your Research & Development.
(2) Modify the Modules / Components to the Next Level for Your Research & Development.
(3) Integrate Different Modules / Components in the OCSim Package to Realize Your Own Fiber Optic Communication Systems.
(4) Modify the Modules for Co-Simulations with the Third Party Commercial Optical Communication Systems Softwares.

 

Main Module

ofdm_qam.m

Simulation of linear and nonlinear single polarization CO-OFDM fiber optic communication systems.


This Module calls the following Sub Modules and Components:

(1) qam_ofdm_transmitter.m
Performs the IFFT of the data sequence.

(2) power_meter.m
Calculates the average optical power in dBm units.

(3) fiber_prop.m
Propagation in optical fiber (takes into account fiber dispersion and loss).

(4) amp.m
Multiplies the input signal by gain factor and adds noise (the amount of noise is controlled by n_{sp}).

(5) opt_rect_filt.m
Optical ideal band pass filter to truncate the spectrum.

(6) AtoD_convert.m
Analog to digital converter. The resolution N_{res} should be specified.

(7) DtoA_convert.m
Digital to analog converter. The resolution N_{res} should be specified.

(8) ofdm_receiver.m
Performs the FFT operation.

(9) ber_calc_qam_ofdm.m
Calculates the symbol error rate.


Explore Further this Module:

9b.1 Change the number of subcarriers from 64 to 2048. Keep the symbol rate fixed at 12.5 GBaud and keep the tmax (and tmin) fixed. Calculate symbol error rate in each case. Compare the computational time as a function of the number of subcarriers. Change the guard interval if necessary to preserve the carrier orthogonality.

9b.2 Change the transmission distance from 1600 km to 3200 km. Change the launch power if necessary so that BER is in the range of  10^{-3} to  10^{-2}. Change the guard interval so that carrier orthogonality is preserved. Plot the symbol error rate as a function of the guard interval.

9b.3 Change the resolution of the A to D (and D to A) converter from 2 bits to 8 bits and plot the symbol error rate as a function of the resolution.

9b.4 Design and simulate following QAM-M coherent optical OFDM fiber optic system links:

10 Gb/s, 512 subcarrier, 40 span QAM-M CO-OFDM fiber optic system link
25 Gb/s, 1024 subcarrier, 20 span QAM-M CO-OFDM fiber optic system link
40 Gb/s, 2048 subcarrier, 10 span QAM-M CO-OFDM fiber optic system link
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n Gb/s, m subcarrier, N span QAM-M CO-OFDM fiber optic system link
Choose the desired values of n, m and N for simulations.

Simulate more:

Switch on to Nonlinearity to design and simulate nonlinear QAM-M CO-OFDM fiber optic system links.

 

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Selected Simulated Results Using this Module 

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Block Diagram of an Optical OFDM System

Opt. mod.= optical modulator, P/S = parallel to serial, S/P = serial to parallel

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Simulation Setup – 1
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Block Diagram of an Optical OFDM Transmitter

S/P = serial to parallel, P/S = parallel to serial, DAC = digital to analog converter

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Simulation Setup – 2
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Block diagram of an Optical IQ modulator

MZM = Mach-Zehnder modulator, DAC=digital to analog converter
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Simulation Setup – 3

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Block Diagram of a Single Polarization Optical OFDM Receiver

S/P = serial to parallel, ADC = analog to digital converter, DSP = digital signal processing

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Simulation Setup – 4

 

 

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Real Part of OFDM Data in a Frame at Tx.

(Single Polarization CO-OFDM Fiber Optic Communication Systems)
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Imaginary Part of OFDM Data in a Frame at Tx

(Single Polarization CO-OFDM Fiber Optic Communication Systems)
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Real Part of the Signal after IFFT at Tx

(Single Polarization CO-OFDM Fiber Optic Communication Systems)

 

 

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Imaginary Part of the Signal after IFFT at Tx

(Single Polarization CO-OFDM Fiber Optic Communication Systems)

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OFDM Spectrum Before the Fiber Optic Link

(Single Polarization CO-OFDM Fiber Optic Communication Systems)

 

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Real Data with Equalizer (red) and without Equalizer (green) at Receiver

Original Data is also shown (blue)

(Single Polarization CO-OFDM Fiber Optic Communication Systems)

 

 

 

 

 

 

OCSim Modules details can be seen by clicking the pages below:

OCSim Modules Overview | OCSim Modules (1-18) in the Package

Module (1a) | Module (1b) | Module (1c) | Module (2a) | Module (2b) | Module (2c) | Module (3a) | Module (3b) | Module (4a) | Module (4b) | Module (4c) | Module (4d) | Module (5) | Module (6a) | Module (6b) | Module (7) | Module (8a) | Module (8b) | Module (8c) | Module (9a) | Module (9b) | Module (10) | Module (11a) | Module (11b) | Module (12) | Module (13) | Module (14) | Module (15) | Module (16) | Module (17)


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