Fiber Optic Communications Labs for Emona FOTEx Add-on Board

by Emona Tims

The Emona FOTEx add-on board and lab manual provide a complete lab program in the key concepts of the transmission and manipulation of optical signals in a modern fiber optic communication system. The add-on board is fully integrated with NI ELVIS virtual instruments and self contains all required electrical and optical components needed to perform the experiments. The initial chapters introduce NI ELVIS and FOTEx while the subsequent chapters cover digital communication topics. Access to the complete volume of the Emona FOTEx add-on board lab manual is provided upon purchase of the product.

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LEARNING OBJECTIVES

Students will gain a comprehensive understanding of optical signals in a modern fiber optic communications systems
Students will develop a background in the important digitial communcaitons topics of of digitization, encoding, and mulitplexing.
Students will gain a deeper mathematical understanding of fiber optic communcation systesm due to the engineering "modeling" nature of the FOTEx trainer.

COURSE ALIGNMENT

Level	University
Topic	Fiber Optic Communcations
Style	Laboratory
Prerequisite Skills	Introductory Physics

Included Course Labs

AN INTRODUCTION TO THE NI ELVIS II TEST EQUIPMENT

This experiment introduces students to the NI ELVIS II digital multimeter, variable DC power supplies, oscilloscope and function generator. This lesson also provides a startup procedure for using the oscilloscope for future experiments.

AN INTRODUCTION TO THE FOTEX ELECTRONICS MODULES

This experiment introduces students to several of the Emona FOTEx's (non-optical) modules that are required by most of the experiments in the manual.

PCM ENCODING

Students will use the PCM Encoder module on the Emona FOTEx to convert the following to PCM: a fixed DC voltage, a variable DC voltage and a continuously changing signal. In the process, students will verify the operation of PCM encoding.

PCM DECODING

Students will use the Emona FOTEx to convert a sinewave to a PCM data stream then convert it to the "stepped" version of the message using the PCM Decoder. Students will investigate the spectral composition of the signal and use the PCM Decoder module's output to reconstruct the message.

SAMPLING AND NYQUIST IN PCM

Students will use the Emona FOTEx to convert a sinewave to a PCM data stream then convert it back to an analog signal using the PCM Decoder module and the 3kHz Low-pass Filter module.

TIME DIVISION MULTIPLE ACCESS (TDMA)

For the experiment students will use the Emona FOTEx to set up a single-channel PCM communications system with an analog input. After which, students will modify the set-up to encode transmit, decode, and reconstruct two analog signals to implement a dual-channel PCM - TDM system and model a simple tow node TDMA telecommunications system.

LINE CODING AND BIT-CLOCK REGISTRATION

For this experiment students will examine the four FOTEx line code equivalents for a 31-bit TTL digital data signal in the time domain and compare them to their theoretically predicted waveshape. Next students will examin signal in the frequency domain. Finally students implement a PCM encoding-decoding system using the board's bit-clock regenerator module.

AN INTRODUCTION TO THE FOTEX FIBER OPTICS COMPONENTS*

This experiment provides an introduction to the fiber optic components available on the FOTEx experimental add-on board. Students will know more about the basic operation of optical fibers and optical communication devices such as couplers, filters, transmitters, and receivers. *This module requires the additional Emona FOTex-Series-II Kit. This kit can be purchased directly from Emona (P/N: ETT-211-32)

GUIDING LIGHT USING TOTAL INTERNAL REFLECTION*

This experiment aims to give student practical experiments with equations, calculations, and the experimental measurement of the angle and intensity of incident, reflected and refracted beams due to changes in refractive index. Students will be introduced to the phenomenon of total internal reflection and will measure the acceptance angle and numerical aperture of a plastic optical fiber. *This module requires the additional Emona FOTex-Series-II Kit. This kit can be purchased directly from Emona (P/N: ETT-211-32)

LOSSES IN FIBER OPTIC NETWORKS*

For this experiment students will investigate the effects of optical reflection, scattering and absorption which are the principal causes of losses in fiber optic networks. Students will also quantify losses of these kinds both as a percentage and as an attenuation figure in decibels. *This module requires the additional Emona FOTex-Series-II Kit. This kit can be purchased directly from Emona (P/N: ETT-211-32)

POLARIZATION*

For this experiment students will explore and manipulate the polarization of light, comparing the polarization of beams from a laser and an LED and use equations to predict the theoretical intensity of light passed by a polarized placed at an angle to a linearly polarized light beam. This experiment also introduces quarter-wave plates to build an optical isolator. *This module requires the additional Emona FOTex-Series-II Kit. This kit can be purchased directly from Emona (P/N: ETT-211-32)

BENDING LOSSES IN FIBER OPTIC SYSTEMS *

This experiment explores the reduction in the light guiding efficiency of fibers due to bending. At the end of the experiment students will have observed and measured light loss due to a bending as a function of bending radius. Students will have an appreciation of the importance of maintaining the quality of the interface between the fiber core and cladding. *This module requires the additional Emona FOTex-Series-II Kit. This kit can be purchased directly from Emona (P/N: ETT-211-32)

CONNECTORS*

This experiment aims to familiarize you with connections between fibers. On completion, students should be familiar with the losses associated with connector and the minimization of back reflection losses using index matching. Students should also be more familiar with loss measurement calculations. *This module requires the additional Emona FOTex-Series-II Kit. This kit can be purchased directly from Emona (P/N: ETT-211-32)

COUPLERS*

This experiment aims to familiarize students with general coupler principles. On completion, students will appreciate and be able to measure some important characteristics of couplers including insertion loss, excess loss and back reflection. Students should also be more familiar with common types of fiber optic measurement and experience some of the measurement pitfalls. *This module requires the additional Emona FOTex-Series-II Kit. This kit can be purchased directly from Emona (P/N: ETT-211-32)

WAVELENGTH FILTERS*

This experiment aims to familiarize students with wavelength filters; simple devices that extract light of a single color from a signal comprising light of different colors. Students will quantify the losses of both red and green filters when transmitting red or green lights and consider how effective the would be at isolating a signal carried by light of a single color form a mixture of different colored light signals. *This module requires the additional Emona FOTex-Series-II Kit. This kit can be purchased directly from Emona (P/N: ETT-211-32)

ANALOG FIBER OPTIC COMMUNICATIONS

Students will characterize the nature of analog (light) signal communications, starting by looking at the properties of the FOTEx LED transmitters to select the most applicable analog drive signals. Next students will determine the most appropriate setting to detect the light sent via a fiber in preparation for transmitting a model analog message. Students then complete the experiment by transmitting a complex message (speech) signal without distortion.

PCM - TDM 'T1' IMPLEMENTATION

Students will use the Emona FOTEx to set up a single-channel PCM communications system with an analog input. After which, they will modify the setup to encode, transmit, decode, and reconstruct two analog signals to implement a dual-channel PCM - TDM system and model a simple TDM telecommunications system. Students will compare the effectiveness of a copper wire versus an optical channel for this communication scheme.

WAVELENGTH DIVISION MULTIPLEXING (WDM)

For this experiment students will use the Emona FOTEx to transmit two discrete message signals along an optical fiber in the same direction with light of different color by using wavelength division multiplexing (WDM). Students will use the set-up to investigate the need for color filtering to recover just one of the messages. Ultimately students will set up a WDM with TDM to transmit and receive three channels of information.

Requirements

NI ELVIS II/II+

The NI Educational Laboratory Virtual Instrumentation Suite (NI ELVIS) is a versatile laboratory platform that enables educators to teach over 20 different courses across science and engineering departments. The NI ELVIS integrates 12 common lab instruments including an oscilloscope, function... Learn more

Emona FOTEx Add-on Board

The Emona FOTEx Add-on Board is a hands-on, experimental approach to teaching introductory digital and optical communication topics such as encoding, multiplexing, polarization, and many more. Learn more

LabVIEW

LabVIEW is systems engineering software for applications that require test, measurement, and control with rapid access to hardware and data insights. Learn more

DETAILED REQUIREMENTS

Required Software

Download Academic Software, Learn About Software Licensing

LabVIEW (Requires License)
ELVISmx

Required Hardware

Purchase Engineering Education Products

NI ELVIS II/II+ - View Specifications View User Manual
Emona FOTEx add-on board - View Specifications

Resources

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