OptiSystem Applications

Migrating to 10Gbps in Metro Networks

In this example, we will investigate the issues at high data bit rate, particularly 10 Gbps (OC-192) systems in metro area ring networks. At higher bit rates, in addition to loss compensation, we may also need to consider the chromatic dispersion compensation. Different options related to dispersion and initial chirp will be investigated. For this…

Negative Dispersion Fiber for Metro Networks

In this example, we compare two types of fibers, Corning’s MetroCor and SMF-28 fibers for metro network applications. MetroCor Fiber has a negative dispersion, whereas SMF-28 has a positive dispersion in the EDFA bands. Dispersion characteristics of these two fibers are shown in Figure 1. For metro applications, directly modulated lasers (DMLs) are preferred because…

Interchannel Crosstalk in Metro Networks

A particular signal can accumulate cross-talk from different elements and channels over the network. Cross-talk can be reduced by using several techniques such as wavelength dilation or filter cascading. In this example, we will investigate the effect of interchannel cross-talk at ADM to a ring network.

WDM Ring – Wavelength Independent Subscriber Equipment

In this example, we will show realization of a WDM ring network using wavelength independent subscriber equipment to share bandwidth [1]. The metro-ring network we modeled operates with 2 wavelength carriers as shown in Figure 1. In this configuration, several subscribers share the bandwidth. For illustration purposes, the network contains one Network Node (NN) and…

Digital Modulation – DPSK

The purpose of this lesson is to demonstrate how to design an 8 DPSK pulse generator using the OptiSystem component library. This tutorial includes references to project files that demonstrate some of the steps presented here. Refer to the end of the tutorial for the project file names. You should use the OptiSystem Component Library…

Digital modulation – OQPSK

The OQPSK modulation is a PSK modulation, using 2 bits per symbol and a delay of one bit in the in quadrature signal (refer to OptiSystem component library, OQPSK Pulse Generator). The project file “OQPSK – Transmitter and Receiver.osd” has an OQPSK transmitter and receiver (Figure 1).

Digital modulation – QAM

Introduction The QAM modulation is typically used in CATV system for cable modem transmission. The project file The project file “QAM – Transmitter and Receiver.osd” has an QAM transmitter and receiver (Figure 1) using a 64 QAM transmission (6 bits per symbol). Figure 1: 64 QAM System The main difference from the DPSK project is…

Manchester and PAM Coding/Decoding

A Manchester encoded signal contains frequent level transitions which allow the receiver to extract the clock signal and correctly decode the value and timing of each bit. To allow reliable operation, the transmitted bit stream must contain a high density of bit transitions. Manchester encoding ensures this, allowing the receiving to correctly extract the clock…

Using OptiSystem to analyze CATV systems

The aim of this material is to show the possibilities of using OptiSystem to analyze CATV systems.
In Part I, we demonstrate the basic nonlinear distortions that result from the propagation of the multiple carrier frequencies through a laser diode.
Observation of harmonic and intermodal products is presented. Although the appearance of the nonlinear distortions is a deterministic process, it is considered to contribute to the laser noise.

Differential Mode Delay and Modal Bandwidth

For the differential mode delay measurement (DMD), an 850 nm probe is scanned at small radial increments across the core of the multimode fiber under test.
At each position the temporal response to a short impulse is recorded. After removal of the reference pulse temporal width, the DMD temporal width is determined at the 25% threshold level between the first leading edge and the last trailing edge of all traces encompassed between specified radial positions.