Basics on Fiber opticsWavelength http://

en.wikipedia.org/wiki/Wavelength Visible – The visible light that we see is just

above Infrared. Recall how white light shown through a prism is broken down into the colors of a rainbow. This concept will be used in expanding the bandwidth of a single fiber optic cable.

Different colors have different wavelengths Infrared: http://en.wikipedia.org/wiki/Infrared

Review - Engineering Notation – Numbers ≥1

Abbreviation Units Prefix Multiplier Power of 10

T Tera- x 1,000,000,000,000 x 1012

G Giga- x 1,000,000,000 x 109

M Mega- x 1,000,000 x 106

K Kilo- x 1,000 x 103

Engineers only use powers of ten that are multiples of 3.

Scientific Notation – Numbers ≥1

1,000,000,000 = 1 x 109

100,000,000 = 1 x 108

10,000,000 = 1 x 107

1,000,000 = 1 x 106

100,000 = 1 x 105

10,000 = 1 x 104

1,000 = 1 x 103

100 = 1 x 102

10 = 1 x 101

1 = 1 x 100

Multiplier Power of Ten

Engineering Notation – Numbers <1

m milli-

µ micro-

n nano-

p pico-

1.001

1000

1.000001

1, 000, 000

1.000000001

1, 000, 000, 000

1.000000000001

1, 000, 000, 000, 000

= x 10-3

= x 10-6

= x 10-9

= x 10-12

Abbrev. Units Prefix Multiplier Power of 10

Engineers only use powers of ten that are multiples of 3.

Basic frequency breakdownRadio waves up to 1GHzMicrowaves up to 150 THzLight up to 1500 THzX-Ray up to 500,000 THzGamma rays above that

Wavelengths A wavelength is the distance between repeating units

of a propagating wave of a given Frequency. It is commonly designated by the Greek letter lambda (λ). Examples of wave-like phenomena are light, water, waves in the ocean, and sound waves.

The wavelength is related to the frequency by the formula: wavelength = wave speed / frequency.

Wavelength is therefore inversely proportional to frequency.

Waves with higher frequencies have shorter wavelengths. Lower frequencies have longer wavelengths, assuming the speed of the wave is the same.

Wave lengths as it relates to distance

Infrared, note where Radar, TV and Radio fall in the spectrum

Types of fiber cableMultimode –850 nm & 1300 (nano-meters)Single mode 1330 nm 1550 nmBasic components of a Fiber strand for either a multimode or single

mode fiber Buffer/coating Cladding Core

MultimodeWavelength:s (λ) [850 nm] Frequency: (352.94118) [GHz] 1300 nm 230.76923 [GHz]Singlemode 1310 nm 229.00763 [GHz] 1550 nm 193.54839 [GHz]

Nano meters

m milli-

µ micro-

n nano-

p pico-

1.001

1000

1.000001

1, 000, 000

1.000000001

1, 000, 000, 000

1.000000000001

1, 000, 000, 000, 000

= x 10-3

= x 10-6

= x 10-9

= x 10-12

Abbrev. Units Prefix Multiplier Power of 10

Engineers only use powers of ten that are multiples of 3.

Light path within a multimode fiberNote the different paths for light to take. This is where the term multi mode comes from-multiple paths or modes

Types of Fiber and there output

Note the input of the fiber on the previous slide for multimode fibersNow look at the output. See how the light pulse

(photons) spread at the output. This is call modal dispersion.

The output is no longer squared off but looks like a bell curve.

The photons that travel straight through get to the end the quickest and that is where you see the output level first start coming up on the right side of the bell curve.

The photons that ricochet the most get to the end last and form the left side of the bell curve.

The majority fall in the middle of the curve.

Plastic versus glassPOF has been called the "consumer" optical fiber

because the fiber and associated optical links, connectors, and installation are all inexpensive.

The traditional plastic fibers are commonly used for low-speed, short-distance (up to 100 meters) applications in digital home appliances, home networks, industrial networks (PROFIBUS, PROFINET), and car networks.

Glass - This fiber has a core made of germania-doped silica. Although the actual cost of glass fibers are lower than plastic fiber, their installed cost is much higher due to the special handling and installation techniques required but, greater distances and higher bandwidth are provided---

Qualifier – in labs nowThanks to a new technique for data transmission, they

have actually succeeded in transmitting one gigabit per second over a 100 meter long test route in the laboratory – without errors or flickering on the screen.

Thanks to quadrature amplitude modulation with up to 256 signal states, the so-called bandwidth efficiency measured in bits per second and hertz can be increased significantly,” explained Sebastian Randel, project manager at Siemens Corporate Technology. Thanks to their algorithm, the researchers could finally transmit exactly 1008 megabits per second through a polymer fiber cable.

Single mode versus MultimodeSingle mode

up to 40Gbs with WDM http://en.wikipedia.org/wiki/Wavelength-division_multiplexing

harder to terminateFactory recommend terminationsLong haul applications

Mulitmode up to Gbs speedson site termination Gigabit to 275m to 2kmModal dispersion limits multimode fiber use to relatively short

runs--typically no more than a few hundred meters at gigabit ethernet

Video coax to fiber transceivers

$69.50 10/ 100 Media Converter

$73510/100/1000 Media Converters

UWGB Campus configuration62.5 multimode between closetsSome composite cables – both single mode

and multimode fibers. Single mode for future expansion

strands vary between 6 and 24 countTelecom closet to server farm (MDF or

equipment room) Fiber feeds the switchesTelecom closet – where the switches are

locatedSwitches to workstations – copper

FTTD? when

SONET – at a very high levelSynchronous Optical Network - SONETState wide system SinglemodeOC 3 or higher depending on legSONET rings, known as "self-healing rings," use

two or more transmission paths between network nodes, which are typically digital cross-connects (DCSs) or add/drop multiplexers (ADMs). If there is a break in one line, the other may still be available, providing the second is not in close proximity to the first and also damaged.

SONET Ring: All data is transmitted on the working or active path, while the standby path (protection path) lies in waiting. When a failure in the active path occurs, the two network nodes affected immediately switch to the standby line.

MultiplexingWMD (no not that WMD)

Multiplexing of multiple optical carriers by using different wavelengths (colors) of laser light to carry different signals.

WDM wavelengths are positioned in a grid having exactly 100 GHz (about 0.8nm) spacing in optical frequency, with a reference frequency fixed at 193.10 GHz (1552.52nm).

Modern systems can handle up to 160 signals and can thus expand a basic 10 Gbs fiber system to a theoretical total capacity of over 1.6 Tbs over a single fiber pair.

Form of FDMReference is made to the varying wavelength of the laser light

rather than frequencyA WDM system uses a multiplexer at the transmitter to join the

signals together, and a de-multiplexer at the receiver to split them apart.

DWDMDWDM works by combining and transmitting multiple

signals simultaneously at different wavelengths on the same fiber. In effect, one fiber is transformed into multiple virtual fibers.

Currently, because of DWDM, single fibers have been able to transmit data at speeds up to 400Gb/s.

Commercial systems capable of carrying 128 signals, DWDM systems use 50 GHz or even 25 GHz channel spacing for up to 160 channel operation

The difference between WDM and dense wavelength division multiplexing (DWDM) is fundamentally one of only degree. DWDM spaces the wavelengths more closely than does WDM, and therefore has a greater overall capacity.

AssignmentDevelop a fiber related question on

termination, speeds, type of fiber, ...Post question to the discussion section on the

wiki page Digital Communications Fall 2009

Answer questions of two other classmates by Tuesday the following week at midnight – December 1st.

Lab on December 2nd will be terminating Fiber cables!