opto1st
TRANSCRIPT
BENCHMARK
FIBER OPTICS BASICS
BENCHMARK
OFT & OFS are trademark of Benchmark Electronic Systems (P) Ltd. This material and the products described herein are Benchmark proprietary products.
All Rights Reserved. This material may not be copied in whole or in part, nor transferred to any other media or language, without the express written permission of Benchmark Electronic Systems (P) Ltd.
Benchmark Electronic Systems (P) Ltd. reserves the right to make changes to this material and to the equipment described herein without notice. Considerable effort has been made to insure that this material is free of inaccuracies and omissions. However, Benchmark Electronic Systems (P) Ltd. makes no warranty of any kind including, but not limited to, any implied warranties of merchantability and fitness for a particular purpose with regard to this material or the products described herein. Benchmark Electronic Systems (P) Ltd. assumes no responsibility for, or liability for errors contained in this material or for incidental, special, or consequential damages arising out of the furnishing of this material, or the use of this material in operating the equipment, or in connection with the performance of the equipment when so operated.
BENCHMARK
FIBER OPTICS BASICS
BENCHMARK
FIBER OPTICS BASICS
What is Fiber Optics Elements of Fiber Optics Optical Fiber Wavelengths of Operation Optical Devices Optical Connectors Major Advantages Some Practical Disadvantages Major Applications
BENCHMARK
WHAT IS FIBER OPTICS
Transmission of data as light pulses through optical fiber(first converting electronic binary signals to light, and then finally converting back to electronic signals)
TRANSMITTER
RECEIVER
BENCHMARK
ELEMENTS OF FIBER OPTICS
TRANSMISSION– Light Source (such as Infra Red LED
converts pulses to light pulses and sends into optical fiber)
RECEPTION– Photodetector converts back to electrical
pulses
BENCHMARK
PROPAGATION IN FIBER– Light propagates by means of total internal
reflection – Optical fiber consists of two concentric
layers core - inner layer cladding - outer layer
BENCHMARK
– Refractive index of core > cladding - necessary for total internal reflection
– Light entering within acceptance angle propagates through fiber
strike core-cladding interface > critical angle and gets reflected completely
zig-zags down length of core through repeated reflections
fairly lossless propagation through bends also
BENCHMARK
BENCHMARK
OPTICAL FIBER
Multimode(Graded Index 50/125micron, 62.5/125micron etc.,)
Single Mode(8.7/125micron)
Propagation of light in a multimode graded index fiber
BENCHMARK
OPTICAL FIBER CABLE
LOOSE JACKETED FIBER FIBER CABLE FROM ONE CORE TO
SEVERAL HUNDRED CORES ARMOURED CABLE
BENCHMARK
Loose Jacketed Fiber
BENCHMARK
Multi-core Fiber Cable
BENCHMARK
Armoured Cable
BENCHMARK
WAVELENGTHS OF OPERATION
650nm 850nm 1300nm 1500nm (All in infrared wavelength)
BENCHMARK
OPTICAL DEVICES
TRANSMITTERS– LEDs
850nm, 1300nm Low cost, easy to use Used for multimode fiber Special ‘Edge-Emitting’ LEDs for single mode
fiber
BENCHMARK
– Laser Diodes 850nm, 1300nm, 1550nm Very high power output Very high speed operation Very expensive Need specialized power supply and circuitry
BENCHMARK
RECEIVERS– PIN DIODES
850, 1300, 1550nm Low Cost
– APDs (Avalanche Photodiodes) 850, 1300, 1550nm High sensitivity - can operate at very low power
levels Expensive
BENCHMARK
OPTICAL CONNECTORS
Commonly Used: SMA, FC, ST, SC– CONNECTORS– RECEPTACLES– ADAPTORS
BENCHMARK
BENCHMARK
MAJOR ADVANTAGES OF FIBER OPTICS
Large Bandwidth (Extremely high information carrying capacity)
Low loss(Long repeaterless link length/repeater spacing)
EMI Immunity(Even in noisy or hard environments - factory floor, high voltage lines)
BENCHMARK
Compact & Lightweight Security
(difficult to tap) Safety
(Insulator & no sparks - ideal for hazardous environment)
BENCHMARK
SOME PRACTICAL DISADVANTAGES
Fiber is expensive Connectors are expensive
(due to degree of precision involved) Connector installation is time consuming
and require skilled operators Joining (splicing) of fibers requires special
equipment/devices and skilled operators
BENCHMARK
Connections & joints are relatively lossy Relatively careful handling required
BENCHMARK
MAJOR APPLICATIONS
TELECOM ISDN FACTORY AUTOMATION SENSORS NETWORKS - LANs, WANs
BENCHMARK
DEFENCE– BUILDINGS– ON-BOARD COMMUNICATIONS
RAILWAYS
BENCHMARK
SINGAPORE:
BENCHMARK SYSTEMS (S) PTE. LTD.
Tel: 65 - 749 - 3372
Fax: 65 - 749 - 3326
E-mail: [email protected]
INDIA:
BENCHMARK ELECTRONIC SYSTEMS (P) LTD.
Tel: 91 - 44 - 413866, 491 0054
Specifications subject to change without notice Fax: 91 - 44 - 491 0123
Copyright © 1996 E-mail: [email protected]