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100 Gbps DP-QPSK System with Digital Signal Processing

The combination of polarization-multiplexing and quadrature phase-shift-keying (PM-QPSK or DP-QPSK) is emerging as one the most promising solutions to reach bit rates of 100 Gbps and higher. At the receiver end, the use of digital signal processing (DSP) results in significant deployment improvement over the traditional implementation.

This example demonstrates a practical design example of a 100 Gbps DP-QPSK transmission system using coherent detection with digital signal processing for distortion compensation (illustrated in the above video).

OFDM Design - Direct and Coherent Detection

As the demand for high transmission data rates rise, there becomes an increasing research interest in orthogonal frequency division multiplexing (OFDM) modulation formats. OFDM is a multi-carrier transmission technique which divides the available spectrum into several carriers, each one modulated by a lower data rate stream.

This Application Note demonstrates the simulation of direct & coherent-detection optical OFDM (DD-OOFDM/CO-OOFDM) systems using OptiSystem. 

DWDM Design

Dense Wavelength Division Multiplexing (DWDM) systems are popular for their cost effective optmization of existing optical networks without the need to add additional fiber. In this DWDM system we simulate the prechirping and modified duobinary modulation format for suppression of intrachannel nonlinearities in 40 Gb/s WDM transmission systems.

OCDMA Design

Optical Code-Division Multiple-Access (OCDMA) system simulation is crucial for optical engineers designing networks that require high levels of privacy and security. This Application Note describes how OptiSystem simulates such a network.

Analysis and Simulation on Spectral Phase-Encoded OCDMA System (subscription required)

Abstract
This paper analyzes the temporal behavior of pseudo-random code and the effects on a spectral phase-encoded time-spreading OCDMA System. A spectral phase-encoded time-spreading optical code division multiple access system designed by Optiwave's Optisystem was demonstrated. The system's performance was simulated under the different pseudo-random phase codes. The OCDMA system's performance would be better if the phase codes have equal amount of 1 and -1 and improved by increasing phase code length. The system performance is evaluated by the Bit Error Rates (BER).

Characterization of the chirp in semiconductor laser under modulation (subscription required)

Abstract
In this paper we present, shortly, a study of the chirp induced in direct modulated DFB laser. Our description of the chirp is based, first on analytical resolution of the rate equations, and second on a simulation of a heterodyne system with the Optisystem software. This study enables us to visualize the chirp of a DFB laser in the RF field and to characterize it according to the parameters of the modulation of the injection current i(t). We show by using the powerful Volterra series theory that the linear sweep of the laser optical frequency can be obtained by a triangular modulation of the injection current.

Design and simulation of a novel phase-encoded OCDMA system

Abstract
The security of optical code division multi-access (OCDMA) system was analyzed, and the results indicate the hidden trouble of security. A scheme of multi-codes to be transmitted single-user information has been proposed, and single-user eavesdropping model has been simulated. The soft platform of system simulation was built by optisystem and MATLAB. The simulation analysis of the system has been accomplished on the soft platform. The brute-force searching and a code interception have been studied. The simulation results have shown that this system has better security.

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