MikMek | Micro- | Multimedia Guide for Promax EF 970 Labs

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Multimedia Guide forPromax EF 970 Labs
KAREL PERUTKA, LUBOMIR MIKMEK
Faculty of Applied Informatics
Tomas Bata University in Zlin
Nam. T.G.Masaryka 5555, 760 01 Zlin
CZECH REPUBLIC, EUROPEAN UNION
kperutka@fai.utb.cz http://web.fai.utb.cz
Abstract: The paper deals with multimedia guide applied on fibre optics, optical communication. There are
several video tutorials focused on software products, which means that they can be used directly in education.
On the other hand, multimedia guide focused on fibre optics and laboratory setup for fibre optics
communication was missing in the laboratory. This paper tries to fill in the gap in this area. The created
multimedia guide is located on DVD/ROM and each measurement can be now realized in short time due to the
created multimedia guide.
Key-Words:Fibre optics, optical communication, multimedia guide, information systems, e-learning, photo
detector
Transmission in optical fibers, physical
principles
- Source of emission and detectors, optical
communication system
- Modern optical components, their
parameters and usage
- Optical multiplexes WDM
- Optical fiber sensor
Mathematical Educational setup is based on
plastic fibers. Optical elements are easy-tomanipulate and resistant against mechanical stress.
Transmission in the visible part of the spectrum
provides objective example of experiments. The
setup is very useful as an introductory teaching aid
in the area of fiber optics. The setup consists of the
basic tool EF-970 and two enlargements which are
denoted as EF-970-01 and EF-970-02.
The basic tool EF-970 includes multifunctional
optical emitter and multifunctional optical receiver,
set of optical modules, optical line, connectors and
cleaning kit.
The setup provides the complex introduction in
the area of optical transmission systems. It allows us
to measure optical loss of optical fibres and wires,
spectral dependence of attenuation, parameters of
optical radiation sources (LED and laser – transfer
and
volt-ampere
characteristics,
stability,
modulation properties). Because the setup includes
several types of detectors (PIN, APD ) made of
several detection materials (Si, Ge, InGaAs) , it is
also possible to study the detectors parameters
(sensitivity, spectral dependence, modulation
properties etc.)
-
1 Introduction
Communication among people play important role
in human life. It is no surprise that there was rapid
increase of communication using electronics in the
20th century. Later on alternatives in communication
was developing due to the lack of information
transmission capacity using radio communication.
Optical communication was one sector which tried
to solve the problem. The speed of light was the
strong argument to start research and development
in this area.
It can be said that the beginning of fibre optics is
deep in 19th century when Daniel Colladon
demonstrate the principles. Sun light went through
water basin directly in water current [1].
The paper is organized as follows. After
introduction part there is setup description
describing the communication setup according to its
manual. The figures of setup are provided as well to
demonstrate the possibilities of setup in more detail.
Setup description part is followed bythe multimedia
guide part which describes the created teachers and
students manual. Next chapter is focused on
randomly selected lab which it describes. The
results of measurements are provided in table and in
graph.
2 Setup Description
Educational communication setup Promax EF-970
is a complex teaching aid [2], [3] which is focused
on:
- Parameters of optical fibers, measurements
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Fig. 3 Transmitter Module – right view
Fig. 1 Accessories of Setup
2.1Multifunctional Transmitter Module
Multifunctional transmitter has two independent
channels for signals denoted as CH1 and CH2. It is
possible to transfer two inputs to chosen optical
outputs. It is possible to use 8 inputs namely signal
generator, external DC input, external AC input,
external microphone, external digital input, external
inverted digital input, digital one, change of zero
and one by button. Emitter has built-in signal
generator generating sine, saw or square signal.
There are six outputs from the transmitter, LED 526
nm, LED 590 nm, LED 660 nm, LED 850 nm, LED
1300 nm and laser 635 nm. Moreover, the emitter
includes built-in mili-ammeter to measure transfer
WA characteristic of LED diodes and laser. The
laser emitter has safety optical protection and
stabilization of operation point.
Fig. 4 Transmitter Module – left view
2.2Multifunctional Receiver Module
Multifunctional receiver has two independent signal
ways (analogue and digital) which allow us optimal
reception of analogue and digital signals by two
independent channels. Built-in photo detectors
enable us to demonstrate several spectral sensitivity,
several detection speeds etc. and they are Si
detector 1 mm, InGaAs detector 1 mm, Ge APD
detector 0.1 mm, and Si detector 2.5 mm. Receiver
has built-in optical power meter which is calibrated
for measurements of several wavelength. The
multifunctional receiver has the following outputs:
digital output (TTL signal), analogue, external
earphones (loudspeaker).
Fig. 2 Transmitter Module – front view
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– ST connectors LED and laser diods). Buttons set
the following behavior of the transmitter module: 1)
input from channel 1 (signal from internal generator,
external analogue signal, input from external
microphone), 2) input from channel 2 (same type of
signals as from channel 1), 3) current display of the
selected output, 4) output selection for channel 1
(LED or laser), 5) output selection for channel 2.
Potentiometers set the gain for channel 1 and 2, and
output current magnitude for channels 1 and 2.
Receiver includes also 5 buttons and several
controls. On the left and right side of the module,
there are located inputs for photo detectors (left – 4
ST connectors and 1 external input for 3.5 mm jack)
and outputs (right – 2 BNC connectors for analogue
and digital signal and one 3.5 mm jack for
earphones or speaker). Buttons set the following
behavior of the receiver module: 1) selection of
analogue channel input (photo detector 1 to 4), 2)
selection of digital channel input (photo detector 1
to 4), 3) selection of optical power meter (analogue,
digital, 1 kHz, DC), 4) selection of optical power
meter units ( W or dBm), and 5) reference value
adjustment. There are seven potentiometers as a
part of receiver. Micro switch denoted as
WAVELENGTH sets the wavelength for the
measurement according to the selected photo
detector. Other switches activate and deactivate
100 kHz and 1 MHz filters, sets the output
impedance of analogue channel and output digital
signal.
Fig. 5 Receiver Module – front view
Fig. 6 Receiver Module – left view
3 Multimedia Guide
There was created the multimedia guide in the
Czech language illustrating the possibilities of the
educational communication setup. The main
purpose of this guide was to easy the student first
steps in the area of labs from the fibre optics.
According to the original documentation from Spain
there was created the multimedia guide of following
tasks: measurement of optical power, measurement
of optical fibre attenuation using the method of
insertion attenuation, spectral dependence of optical
fibre attenuation, influence of surrounding optical
radiation, interconnection of optical fibers using ST
connector and measurement of interconnection
reproducibility, measurement of transfer WA
characteristics of optical radiation source,
measurement of power stability of optical radiation
sources, measurement of VA characteristics of
optical radiation sources, modulation properties of
optical radiation sources, spectral dependence of
photo detectors, photo detectors sensitivity, photo
detectors bandwidth, analogue signal transmission,
audio
signal
transmission,
digital
signal
Fig. 7 Receiver Module – right view
2.3Education Setup Handling
Transmitter includes 5 buttons and several controls
such as potentiometers, micro switches, which are
located on the board of the module. On the left and
right side of the module, there are located inputs
(left – BNC connectors analogue and digital,
microphone input – 3.5 mm jack) and outputs (right
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transmission, influence of fibre flection to optical
fibre attenuation, measurement of optical aperture,
influence of nonideal interconnection of optical
fibres to their attenuation, measurement of optical
branch, measurement of attenuation of optical
attenuator, spectral dependency of optical attenuator
attenuation, comparison of noise properties of
several photodetectors, WDM: multiplexing and demultiplexing, WDM transfer, transmission sensor,
reflection sensor, liquid level sensor, and
transmission sensor of liquid presence.
Multimedia guide includes two DVD-ROM,
teacher video manual is in the first one, and students
one is in the second. Teacher video manual has also
the results of the measurements included in the
manual while the students’ video manual does not
have them.
The guide was created in Nero 11 Shareware,
namely in Nero Video [4]. Nero Video is used for
complex editing of multi tracks with special effects
included. The created guide was then burned in
Nero Burning ROM.
Measured labs are sorted in the multimedia guide
according to their complexity. First labs are
introductory ones, they demonstrate the basic
functions of the educational communication setup.
Results of measurements, which are included in the
teacher video manual, are only informatory ones.
The multimedia guide starts automatically after
DVD ROM insertion into the DVD ROM drive, the
main screen of video manual is opened. Each lab is
included in the DVD ROM as a special chapter.
Not all chapters are displayed in one screen and,
therefore , there are buttons for listing among
screens with several labs.
- list of used measurement apparatuses and
accessories
- if there is some accessory which wasn’t used in the
previous labs, it is shown graphically
- setting the values at transmitter and receiver
(displays values on screen)
- playing the video with selected parameters of the
measurements
- measuring procedure with tables if necessary
- showing the results , tables are empty in the
students manual
- measurement notes
Fig. 8 Multimedia Guide – Chapters Menu
4.4 Results
In table 1 and figure 9, there are measured results of
the selected lab obtained using Promax EF 970
Fibre Optics Communication Setup for several
voltage values.
4 Sample Lab 1
Measurement of photo detector bandwidth was
randomly selected as lab 1[3].
4.1 Task
Measure the photo detector bandwidth. Measure the
influence of cut-off voltage on the detector
bandwidth.
4.2 Devices, Aids, Materials
Oscilloscope, volt meter, signal generator (square
and sine signal, maximum frequency 10 MHz),
cables, cleaning set.
4.3 Practice
Using the buttons of multifunctional transmitter
module set the following: input from signal
generator, channel CH1, sine signal, frequency 1
kHz, optical output: source #4 (LED 850 nm) for
channel CH1. At multifunctional receiver module
set the function Analogue measurement, photo
detector #1 (Si 1 mm) as optical output, wavelength
850 nm, output impedance 75 Ohm. Interconnect
signal generator with receiver module, its DC input.
Connect the first probe of the oscilloscope to testing
output of the receiver module and second probe with
test point TP10 and GND. Use the connecting cable
and connect the corresponding output of the
transmitter module with the corresponding input of
the receiver module. Connect volt meter to the test
point TP17 and GND, you will measure the photo
detector cut-off voltage (UBIAS).
3.1Characteristics of Labs in Video Manual
Measured labs follow the following order in the
video manual
- main screen with the name of the lab together
with task assignment
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Fig. 9 Photo detector bandwidth
5 Sample Lab 2
Spectral dependence of insertion losses of variable
optical attenuator was randomly selected as lab 2
[3].
5.1 Task
Measure spectral dependence of insertion losses for
a variable optical attenuator.
5.2 Devices, Aids, Materials
Cable patchcord, variable attenuator, cleaning
components.
5.3 Practice
After connecting outputs of transmitter and inputs of
receiver, setting the values of optical source current
according to the instructions, connecting variable
attenuator and setting its position according to the
instruction list we measure the real attenuation of
attenuator for several wavelengths. Transmitter is
set by following way. Input DC without connection
on channel CH1, mA measurement for CH1, photo
emitter #3 (LED 660 nm) on channel CH1 is optical
output. And receiver is set by following way. DC
measurement as function, photo detector #4 (PIN Si
2.5 mm) on analogue channel is optical input and
measurement is realized for 660 nm wavelength.
By setting 0 dB value at the variable attenuator,
the new reference value is realized. This is followed
by setting the values of attenuation according to the
table 2 and we write real values of attenuation
(measured ones) in the table. Measurements are also
repeated for other wavelengths. Measured values of
attenuation are compared in table and shown in
graph.
Value of optical source current is set according
to the table 2. Photo detector #2 (PIN InGaAs) was
used for measurements for 1300 nm wavelength.
Table 1 Data of photo detector bandwidth
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5.4 Results
In table 2 and figure 10, there are measured results
of the selected lab obtained using Promax EF 970
Fibre Optics Communication Setup for several
wavelength values.
6 Conclusion
There was presented the created multimedia guide
dealing with PROMAX EF 970 Fibre Optical
Communication. This guide speeds up the
measurements and makes the lab more attractive.
There were exactly created two multimedia guides,
one for students, which do not have the results
shown, and teachers have also their own guide but
with results of measurements included.
References:
[1] Ghatak, A., Thyagarajan, K., An introduction to
fiber optics: Principles and applications,
Cambridge University Press, 1998, ISBN 05215-7785-3.
[2] PROMAX, Fibre Optic Communications
Training System User’s Manual: EF-970B-E,
Hertfordshire, 2002.
[3] PROMAX, Fibre Optic Communications
Training System Practice Manual: EF-970B-E,
Hertfordshire, 2002.
[4] NERO Inc., Reviewer’s Guide NERO 11,
http://nmf.nero.com/branding/Nero_11_Review
rs_Guide_ENG.pdf
Table 2 Data forspectral dependence of insertion
losses of variable optical attenuator
Fig. 10 Graph of spectral dependence of insertion
losses of variable optical attenuator
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