logging in or signing up Optical Fiber ankush85 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 33136 Category: Education License: All Rights Reserved Like it (77) Dislike it (5) Added: May 24, 2009 This Presentation is Public Favorites: 10 Presentation Description No description available. Comments Posting comment... By: vineethjaas (3 month(s) ago) infrmativ..can u pls get me dis ppt in vineethjas@rediffmail.com Saving..... Post Reply Close Saving..... Edit Comment Close By: tecexam (7 month(s) ago) Hi,can please send this ppt to" tecexam@gmail.com" Saving..... Post Reply Close Saving..... Edit Comment Close By: malleshnarayan (7 month(s) ago) Hi,can please send this ppt to" malleshnarayan@gmail.com" Saving..... Post Reply Close Saving..... Edit Comment Close By: gorvie (7 month(s) ago) plz mail me dis presentation,....gauravsingh262@gmail.com Saving..... Post Reply Close Saving..... Edit Comment Close By: akshay601360 (7 month(s) ago) how to download this ppt pls tell me Saving..... Post Reply Close Saving..... Edit Comment Close loading.... See all Premium member Presentation Transcript Optical Fiber : Optical Fiber Optical Fiber : Optical Fiber Communication system with light as the carrier and fiber as communication medium Propagation of light in atmosphere impractical: water vapor, oxygen, particles. Optical fiber is used, glass or plastic, to contain and guide light waves Capacity Microwave at 10 GHz with 10% utilization ratio: 1 GHz BW Light at 100 Tera Hz (1014 ) with 10% utilization ratio: 100 THz (10,000GHz) History : History 1880 Alexander G. Bell, Photo phone, transmit sound waves over beam of light 1930: TV image through uncoated fiber cables. Few years later image through a single glass fiber 1951: Flexible fiberscope: Medical applications 1956:The term “fiber optics” used for the first time 1958: Paper on Laser & Maser History Cont’d : History Cont’d 1960: Laser invented 1967: New Communications medium: cladded fiber 1960s: Extremely lossy fiber: more than 1000 dB /km 1970, Corning Glass Work NY, Fiber with loss of less than 2 dB/km 70s & 80s : High quality sources and detectors Late 80s : Loss as low as 0.16 dB/km Optical Fiber: Advantages : Optical Fiber: Advantages Capacity: much wider bandwidth (10 GHz) Crosstalk immunity Immunity to static interference Safety: Fiber is nonmetalic Longer lasting (unproven) Security: tapping is difficult Economics: Fewer repeaters Disadvantages : Disadvantages higher initial cost in installation Interfacing cost Strength: Lower tensile strength Remote electric power more expensive to repair/maintain Tools: Specialized and sophisticated Optical Fiber Link : Optical Fiber Link Input Signal Coder or Converter Light Source Source-to-Fiber Interface Fiber-to-light Interface Light Detector Amplifier/Shaper Decoder Output Fiber-optic Cable Transmitter Receiver Slide 8: Light source: LED or ILD (Injection Laser Diode): amount of light emitted is proportional to the drive current Source –to-fiber-coupler (similar to a lens): A mechanical interface to couple the light emitted by the source into the optical fiber Light detector: PIN (p-type-intrinsic-n-type) or APD (avalanche photo diode) both convert light energy into current Fiber Types : Fiber Types Plastic core and cladding Glass core with plastic cladding PCS (Plastic-Clad Silicon) Glass core and glass cladding SCS: Silica-clad silica Under research: non silicate: Zinc-chloride: 1000 time as efficient as glass Plastic Fiber : Plastic Fiber used for short run Higher attenuation, but easy to install Better withstand stress Less expensive 60% less weight Types Of Optical Fiber : Types Of Optical Fiber Single-mode step-index Fiber Multimode step-index Fiber Multimode graded-index Fiber n1 core n2 cladding no air n2 cladding n1 core Variable n no air Light ray Index porfile Single-mode step-index Fiber : Single-mode step-index Fiber Advantages: Minimum dispersion: all rays take same path, same time to travel down the cable. A pulse can be reproduced at the receiver very accurately. Less attenuation, can run over longer distance without repeaters. Larger bandwidth and higher information rate Disadvantages: Difficult to couple light in and out of the tiny core Highly directive light source (laser) is required. Interfacing modules are more expensive Multi Mode : Multi Mode Multimode step-index Fibers: inexpensive; easy to couple light into Fiber result in higher signal distortion; lower TX rate Multimode graded-index Fiber: intermediate between the other two types of Fibers Acceptance Cone & Numerical Aperture : Acceptance Cone & Numerical Aperture n2 cladding n2 cladding n1 core Acceptance Cone Acceptance angle, qc, is the maximum angle in which external light rays may strike the air/Fiber interface and still propagate down the Fiber with <10 dB loss. Numerical aperture: NA = sin qc = ?(n12 - n22) qC Losses In Optical Fiber Cables : Losses In Optical Fiber Cables The predominant losses in optic Fibers are: absorption losses due to impurities in the Fiber material material or Rayleigh scattering losses due to microscopic irregularities in the Fiber chromatic or wavelength dispersion because of the use of a non-monochromatic source radiation losses caused by bends and kinks in the Fiber modal dispersion or pulse spreading due to rays taking different paths down the Fiber coupling losses caused by misalignment & imperfect surface finishes Absorption Losses In Optic Fiber : Absorption Losses In Optic Fiber Loss (dB/km) 1 0 0.7 0.8 Wavelength (mm) 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 2 3 4 5 6 Peaks caused by OH- ions Infrared absorption Rayleigh scattering & ultraviolet absorption Fiber Alignment Impairments : Fiber Alignment Impairments Axial displacement Gap displacement Angular displacement Imperfect surface finish Light Sources : Light Sources Light-Emitting Diodes (LED) made from material such as AlGaAs or GaAsP light is emitted when electrons and holes recombine either surface emitting or edge emitting Injection Laser Diodes (ILD) similar in construction as LED except ends are highly polished to reflect photons back & forth ILD versus LED : ILD versus LED Advantages: more focussed radiation pattern; smaller Fiber much higher radiant power; longer span faster ON, OFF time; higher bit rates possible monochromatic light; reduces dispersion Disadvantages: much more expensive higher temperature; shorter lifespan Light Detectors : Light Detectors PIN Diodes photons are absorbed in the intrinsic layer sufficient energy is added to generate carriers in the depletion layer for current to flow through the device Avalanche Photodiodes (APD) photogenerated electrons are accelerated by relatively large reverse voltage and collide with other atoms to produce more free electrons avalanche multiplication effect makes APD more sensitive but also more noisy than PIN diodes Bandwidth & Power Budget : Bandwidth & Power Budget The maximum data rate R (Mbps) for a cable of given distance D (km) with a dispersion d (ms/km) is: R = 1/(5dD) Power or loss margin, Lm (dB) is: Lm = Pr - Ps = Pt - M - Lsf - (DxLf) - Lc - Lfd - Ps ? 0 where Pr = received power (dBm), Ps = receiver sensitivity(dBm), Pt = Tx power (dBm), M = contingency loss allowance (dB), Lsf = source-to-Fiber loss (dB), Lf = Fiber loss (dB/km), Lc = total connector/splice losses (dB), Lfd = Fiber-to-detector loss (dB). Wavelength-Division Multiplexing : Wavelength-Division Multiplexing WDM sends information through a single optical Fiber using lights of different wavelengths simultaneously. Laser Optical sources l1 l2 ln ln-1 l3 l1 l2 ln ln-1 l3 Laser Optical detectors Optical amplifier Multiplexer Demultiplexer On WDM and D-WDM : On WDM and D-WDM WDM is generally accomplished at 1550 nm. Each successive wavelength is spaced > 1.6 nm or 200 GHz for WDM. ITU adopted a spacing of 0.8 nm or 100 GHz separation at 1550 nm for dense-wave-division multiplexing (D-WDM). WD couplers at the demultiplexer separate the optic signals according to their wavelength. You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
Optical Fiber ankush85 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 33136 Category: Education License: All Rights Reserved Like it (77) Dislike it (5) Added: May 24, 2009 This Presentation is Public Favorites: 10 Presentation Description No description available. Comments Posting comment... By: vineethjaas (3 month(s) ago) infrmativ..can u pls get me dis ppt in vineethjas@rediffmail.com Saving..... Post Reply Close Saving..... Edit Comment Close By: tecexam (7 month(s) ago) Hi,can please send this ppt to" tecexam@gmail.com" Saving..... Post Reply Close Saving..... Edit Comment Close By: malleshnarayan (7 month(s) ago) Hi,can please send this ppt to" malleshnarayan@gmail.com" Saving..... Post Reply Close Saving..... Edit Comment Close By: gorvie (7 month(s) ago) plz mail me dis presentation,....gauravsingh262@gmail.com Saving..... Post Reply Close Saving..... Edit Comment Close By: akshay601360 (7 month(s) ago) how to download this ppt pls tell me Saving..... Post Reply Close Saving..... Edit Comment Close loading.... See all Premium member Presentation Transcript Optical Fiber : Optical Fiber Optical Fiber : Optical Fiber Communication system with light as the carrier and fiber as communication medium Propagation of light in atmosphere impractical: water vapor, oxygen, particles. Optical fiber is used, glass or plastic, to contain and guide light waves Capacity Microwave at 10 GHz with 10% utilization ratio: 1 GHz BW Light at 100 Tera Hz (1014 ) with 10% utilization ratio: 100 THz (10,000GHz) History : History 1880 Alexander G. Bell, Photo phone, transmit sound waves over beam of light 1930: TV image through uncoated fiber cables. Few years later image through a single glass fiber 1951: Flexible fiberscope: Medical applications 1956:The term “fiber optics” used for the first time 1958: Paper on Laser & Maser History Cont’d : History Cont’d 1960: Laser invented 1967: New Communications medium: cladded fiber 1960s: Extremely lossy fiber: more than 1000 dB /km 1970, Corning Glass Work NY, Fiber with loss of less than 2 dB/km 70s & 80s : High quality sources and detectors Late 80s : Loss as low as 0.16 dB/km Optical Fiber: Advantages : Optical Fiber: Advantages Capacity: much wider bandwidth (10 GHz) Crosstalk immunity Immunity to static interference Safety: Fiber is nonmetalic Longer lasting (unproven) Security: tapping is difficult Economics: Fewer repeaters Disadvantages : Disadvantages higher initial cost in installation Interfacing cost Strength: Lower tensile strength Remote electric power more expensive to repair/maintain Tools: Specialized and sophisticated Optical Fiber Link : Optical Fiber Link Input Signal Coder or Converter Light Source Source-to-Fiber Interface Fiber-to-light Interface Light Detector Amplifier/Shaper Decoder Output Fiber-optic Cable Transmitter Receiver Slide 8: Light source: LED or ILD (Injection Laser Diode): amount of light emitted is proportional to the drive current Source –to-fiber-coupler (similar to a lens): A mechanical interface to couple the light emitted by the source into the optical fiber Light detector: PIN (p-type-intrinsic-n-type) or APD (avalanche photo diode) both convert light energy into current Fiber Types : Fiber Types Plastic core and cladding Glass core with plastic cladding PCS (Plastic-Clad Silicon) Glass core and glass cladding SCS: Silica-clad silica Under research: non silicate: Zinc-chloride: 1000 time as efficient as glass Plastic Fiber : Plastic Fiber used for short run Higher attenuation, but easy to install Better withstand stress Less expensive 60% less weight Types Of Optical Fiber : Types Of Optical Fiber Single-mode step-index Fiber Multimode step-index Fiber Multimode graded-index Fiber n1 core n2 cladding no air n2 cladding n1 core Variable n no air Light ray Index porfile Single-mode step-index Fiber : Single-mode step-index Fiber Advantages: Minimum dispersion: all rays take same path, same time to travel down the cable. A pulse can be reproduced at the receiver very accurately. Less attenuation, can run over longer distance without repeaters. Larger bandwidth and higher information rate Disadvantages: Difficult to couple light in and out of the tiny core Highly directive light source (laser) is required. Interfacing modules are more expensive Multi Mode : Multi Mode Multimode step-index Fibers: inexpensive; easy to couple light into Fiber result in higher signal distortion; lower TX rate Multimode graded-index Fiber: intermediate between the other two types of Fibers Acceptance Cone & Numerical Aperture : Acceptance Cone & Numerical Aperture n2 cladding n2 cladding n1 core Acceptance Cone Acceptance angle, qc, is the maximum angle in which external light rays may strike the air/Fiber interface and still propagate down the Fiber with <10 dB loss. Numerical aperture: NA = sin qc = ?(n12 - n22) qC Losses In Optical Fiber Cables : Losses In Optical Fiber Cables The predominant losses in optic Fibers are: absorption losses due to impurities in the Fiber material material or Rayleigh scattering losses due to microscopic irregularities in the Fiber chromatic or wavelength dispersion because of the use of a non-monochromatic source radiation losses caused by bends and kinks in the Fiber modal dispersion or pulse spreading due to rays taking different paths down the Fiber coupling losses caused by misalignment & imperfect surface finishes Absorption Losses In Optic Fiber : Absorption Losses In Optic Fiber Loss (dB/km) 1 0 0.7 0.8 Wavelength (mm) 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 2 3 4 5 6 Peaks caused by OH- ions Infrared absorption Rayleigh scattering & ultraviolet absorption Fiber Alignment Impairments : Fiber Alignment Impairments Axial displacement Gap displacement Angular displacement Imperfect surface finish Light Sources : Light Sources Light-Emitting Diodes (LED) made from material such as AlGaAs or GaAsP light is emitted when electrons and holes recombine either surface emitting or edge emitting Injection Laser Diodes (ILD) similar in construction as LED except ends are highly polished to reflect photons back & forth ILD versus LED : ILD versus LED Advantages: more focussed radiation pattern; smaller Fiber much higher radiant power; longer span faster ON, OFF time; higher bit rates possible monochromatic light; reduces dispersion Disadvantages: much more expensive higher temperature; shorter lifespan Light Detectors : Light Detectors PIN Diodes photons are absorbed in the intrinsic layer sufficient energy is added to generate carriers in the depletion layer for current to flow through the device Avalanche Photodiodes (APD) photogenerated electrons are accelerated by relatively large reverse voltage and collide with other atoms to produce more free electrons avalanche multiplication effect makes APD more sensitive but also more noisy than PIN diodes Bandwidth & Power Budget : Bandwidth & Power Budget The maximum data rate R (Mbps) for a cable of given distance D (km) with a dispersion d (ms/km) is: R = 1/(5dD) Power or loss margin, Lm (dB) is: Lm = Pr - Ps = Pt - M - Lsf - (DxLf) - Lc - Lfd - Ps ? 0 where Pr = received power (dBm), Ps = receiver sensitivity(dBm), Pt = Tx power (dBm), M = contingency loss allowance (dB), Lsf = source-to-Fiber loss (dB), Lf = Fiber loss (dB/km), Lc = total connector/splice losses (dB), Lfd = Fiber-to-detector loss (dB). Wavelength-Division Multiplexing : Wavelength-Division Multiplexing WDM sends information through a single optical Fiber using lights of different wavelengths simultaneously. Laser Optical sources l1 l2 ln ln-1 l3 l1 l2 ln ln-1 l3 Laser Optical detectors Optical amplifier Multiplexer Demultiplexer On WDM and D-WDM : On WDM and D-WDM WDM is generally accomplished at 1550 nm. Each successive wavelength is spaced > 1.6 nm or 200 GHz for WDM. ITU adopted a spacing of 0.8 nm or 100 GHz separation at 1550 nm for dense-wave-division multiplexing (D-WDM). WD couplers at the demultiplexer separate the optic signals according to their wavelength.