Fiber Optic Transmission

Slides:



Advertisements
Similar presentations
An Introduction to Refraction SNC2D. Index of Refraction Light will travel more slowly in more dense materials. The ratio of the speed of light in a vacuum.
Advertisements

Lecture 3 Light Propagation In Optical Fiber
© John Parkinson 1 © John Parkinson 2 I think we are being watched! Refraction is the Bending of Waves due to a Change in Velocity Refraction is the.
Chapter 15 Pretest Light and Refraction
Refraction Lesson 4. Objective You will be able to qualitatively and quantitatively describe the behavior of waves as the pass from one medium to another.
Refraction of light. Refraction is the bending of light as it passes from one medium to another.
LIGHT A FORM OF ELECTROMAGNETIC RADIATION THAT STIMULATES THE EYE.
Lecture 4b Fiber Optics Communication Link 1. Introduction 2
Total Internal Reflection
Introduction to Fiber Optics
Optical Fiber Communications
REFRACTION OF LIGHT.
Physics. PHS 5041 Optics Refraction of Light Refraction always occurs simultaneously with some partial reflection Change in direction is with respect.
Light by Rifki Irawan Refraction. Based on how the light behaves as it encounters a substance, substances can be classified into: Transparent substance.
Refraction.
REFRACTION (Bending of Light) Light slows down or speeds up when it enters and leaves another material.
Light - Refraction Sec 3 Physics For E-Learning, please read slides 1 to 10.
Refraction and Snell’s Law. Intro to Refraction Take 3 cups from the front, labeled 1,2,3. Observe each straw through the side of the cup as you slowly.
Refraction. Light Travels in straight lines. We have examined how light can reflect off an object. Today.
LIGHT REFRACTION OF LIGHT
Reflection, Refraction, and Diffraction. Reflection  Reflection – wave strikes a surface and is bounced back. Law of Reflection: angle of incidence =
Refraction. What is Refraction  Refraction occurs when light moves from one medium (material) to another  Because of density differences light will.
THIN LENSES Refraction. What Is Love Light? Isaac Newton believed light to be a ray of corpuscles (particles), because light travels in a straight line.
Light refraction.
A laser pointer is aimed at the surface of a flat mirror. Draw the laser beam after it hits the surface of the mirror.
Light Refraction of Light. Learning Objectives You will learn to recall and use the terms used in refraction, including normal, angle of incidence and.
Refraction. The Optical Density of a Medium The better a medium transmits light, the lower its optical density. The slower light is transmitted by a medium,
Fiber Optic Transmission SL/HL – Option C.3. Reflection/Refraction Reflection – A wave encounters a boundary between two mediums and cannot pass through.
Lecture Outline Chapter 22 College Physics, 7 th Edition Wilson / Buffa / Lou © 2010 Pearson Education, Inc.
Refraction and Snell’s Law Refraction: bending of light at the interface of 2 different materials.
Reflection and Refraction
Lesson 29 Wave Characteristics of Light. Wave Function for Light v=λν i.For light v = 3.0x108m/s according to Einstein (maybe false now????)
Refraction and Snells Law SNC2D Index of Refraction Light will travel more slowly in more dense materials. The ratio of the speed of light in a vacuum.
Refraction of Light Refraction and Lenses
Refraction (Slowing Down) When a wave passes into a medium that makes it slow down, the wave will bend toward the normal Air Water.
the change of direction of a ray of light as it passes obliquely from one medium into another of different transmission speed.
.. What Happened?? Look at the data you collected during the simulation Are the angles the same for every scenario? Why is there a difference?
Putting Light to Work for You Features of Signal Transfer.
Fiber Optic Transmission SL/HL – Option F Mr. Jean.
FIBER OPTIC TRANSMISSION
Week 2 Lesson 2 Critical Angle & Total Internal reflection.
Refraction -Refraction of Sound -Refraction of Light.
CHAPTER 7 Refraction of Light.
Fiber Optics.
Refraction. Light  Tends to travel in straight lines  If you need to bend light or shine it into difficult-to-reach.
IB Physics Option F – Fibre Optics Mr. Jean. The plan: Video clip of the day Fibre Optics – C+-+Imaginghttps://ibphysics2016.wikispaces.com/Option+
12.1 Refraction.
LIGHT Reflection and Refraction. Mirrors and highly polished opaque surfaces reflect light in predictable ways.
The Refraction of Light SNC2P – Optics. Refraction Refraction: the bending or change in direction of light when it travels from one medium into another.
Refraction. Have you ever seen this? Refraction of Light When light travels through a surface between two different media, the light will be refracted.
Chapter 7 Light and Geometric Optics. 7.3 Refraction of Light.
Total Internal Reflection. Can occur when light inside a glass block hits the edge at certain angles Remember – if light hits the boundary between two.
Index of Refraction. The ratio of the speed of light in vacuum to the speed of light v in a given material is called the index of refraction, n of the.
1 Refraction, the Snell law Light in geometric optics is discussed in rays and represented by a straight line with an arrow indicating the propagation.
Reflection and Refraction. Reflection Reflection – some or all of a wave bounces back into the first medium when hitting a boundary of a second medium.
The Refraction of Light, the Index of Refraction, and Snell’s Law
DO NOW What is the color of a light wave with a frequency of 5.65 x Hz?
Lesson 5. Problem: Light enters a prism as shown, and passes through the prism. a)Complete the path of the light through the prism, and show the angle.
Refraction: from air to glass These lines are the crests of waves or WAVEFRONTS: the distance between successive wave fronts is called the WAVELENGTH Glass.
REFRACTION OF LIGHT. BEHAVIOR OF LIGHT Light acts both as a wave and as a particle Called a “wavicle” Light needs to interact with a surface in order.
Happy Tuesday! Get ready for warm up #4 Get out paper for notes. Title them: “Snell’s Law and Refraction” Essential Question: What is Snell’s Law?
RAY THEORY AND OPTICAL WAVEGUIDE BY DR. NEENA GUPTA Assistant Professor E&EC Deptt. Punjab Engineering College,Deemed University,CHANDIGARH.
Physics REVISION – Light - Reflection The law of reflection Sound waves and light waves reflect from surfaces. The angle of incidence equals the angle.
The Critical Angle and Total Internal Reflection.
CfE Higher Physics Particles and Waves
Reflection, refraction and optical fibre
Review of Snell’s Law & Refraction Calculations
Total Internal Reflection
Introduction to Fiber Optics
REFRACTION OF LIGHT.
Presentation transcript:

Fiber Optic Transmission SL/HL – Option F.3

Reflection/Refraction A wave encounters a boundary between two mediums and cannot pass through The angle of incidence is always equal to the angle of reflection Refraction When a wave passes through boundary into a new medium its speed changes The wave will change directions based on the change in its speed

Refraction If the wave speeds up it will bend away from the normal line If the wave slows down it will bend towards the normal line Snell’s Law sinθi cr = sinθr ci

Critical Angle When traveling into air from some medium, light will always speed up, thus increasing the angle If it speeds up enough, the angle of refraction will be 90 degrees This means that the refracted ray will travel along the edge of the boundary

Critical Angle When light strikes the boundary at the critical angle or greater, the wave is totally reflected back into the first medium Here n1 is the index of refraction of the medium the light starts in

Total Internal Reflection Usually when a wave reaches a boundary between mediums it is partially reflected and partially refracted When the critical angle is exceeded the entire wave is reflected back within the medium The wave doesn’t lose any energy

Optical Fiber Fiber optic cable is made of thin, clear glass or plastic Once light enters the cable it is totally internally reflected until it reaches the far end Actual optical fiber is step indexed There is another layer between the core and the outside This is so the fibers can be bundled together

Critical Angle The critical angle is that angle of incidence for which the angle of refraction is 90 degrees. n1 sinθc = n2 sin90 Θc = sin-1 (n1/n2)

Practice Problem A ray of light in water (refractive index 1.33) is incident from water on a water-air boundary. Calculate the critical angle of the water-air boundary.

Practice Problem A ray is emitted at point P is internally reflected. What can you deduce about the refractive index of the liquid? 8cm Air = 1.00 Liquid = ? 12cm

Dispersion Modal Material Not all the waves that enter make it to the other end, only certain ones The possible paths are called modes Material Because different frequencies have different refractive indices, they have different paths These can both cause problems if the bits of data arrive out of order More direct modes are faster Laser light and single mode cable reduce these effects

Acceptance Angle The maximum angle of incidence a ray entering a fibre resulting in total internal reflection is called the acceptance angle. A = sin-1 √(n12 – n22)

Practice Problem The refractive index of the core of an optical fibre is 1.50 and that of the cladding is 1.40. Calculate the acceptance angle of the fibre.

Material Dispersion

Attenuation Attenuation is the opposite of amplification As a signal travels through a cable it will slowly lose intensity as energy is lost Attenuation is measured in decibels (dB) The 10 at the beginning is to convert to decibels Generally measured in dBkm-1

Amplifiers Even with reshaping, signals still attenuate over the length of the cable Amplifiers along the cable increase the signal strength to keep it going The same equation for Attenuation applies to Amplifiers

Practice Problem An amplifier amplifies an incoming signal of power 0.34mW to a signal of power 2.2mW. Calculate the power gain of the amplifier in decibels.

Practice Problem A signal starting with 10mW of power is reduced by 19 decibels over 50km. Calculate the power lost per km.

Wavelength/Attenuation

Reshapers Monomode fibers can eliminate modal dispersion and lasers cut down on material dispersion, but it is not completely eliminated Over a long distance individual pulses can start to overlap each other Every 40-60km is a reshaper which will detect and reshape the signal Has its own laser which sends a ‘new’ signal

Noise One advantage to using fiber optics is that it is not particularly susceptible to noise Any noise that does occur is generally due to random light entering the end of the cable The power ratio of noise to signal in fiber optics is generally in the range of 10-17 or 10-18 Signal to Noise (dB)

Practice Problem The minimum SNR considered acceptable for a certain signal is 30dB. If the power of the noise is 2.0mW, calculate the least acceptable signal power.