03. Optical communications and access networks
EN 63001 – Communication Systems I
(Jun 2018)
Dept. of Electrical & Telecom. Eng., FE, SEUSL
Chinthaka Wasantha (chinthakawk@gmail.com)
Topics
1.
2.
3.
4.
Wired access networks [4]
1.1 Evolution of the public switched telecommunication network (PSTN)
1.2 Digital subscriber loop (DSL) standards and services
Wireless access networks [15 h]
2.1 Wireless channel characteristics
2.2 Fixed and mobile wireless access systems
2.3 Evolution of cellular systems to mobile broadband
2.4 Wireless broadband networks
2.5 Wireless Local Area Networks (LANs) and Personal Area Networks (PANs)
Optical communications and access networks [7 h]
3.1 Fundamentals of optical communications systems
3.2 Optical access networks; configurations and capabilities
Broadcast networks [4 h]
4.1 Evolution of broadcasting from analog to digital
4.2 Digital audio and video broadcasting; systems and standards
Submarine cable map
• https://www.submarinecablemap.com
Fiber cable construction
Fiber cable construction
• There are many different cable designs available today.
• Depending on configuration, the cable may include a core, a cladding,
a protective tube, a polyurethane compound and one or more
protective jackets.
• The fiber cable consist of a core at the center and a cladding outside
the core.
• The buffer jacket provide protection for the fiber from external
mechanical influences that could cause fiber breakage or excessive
optical attenuation.
Fiber cable construction
• Surrounding the buffer jacket there is a layer of strength members
called Kevlar (a yarn type material) which increase the tensile
strength of cable.
• Again, an outer protective tube is filled with polyurethane ,which
prevents moisture from coming into contact with fiber.
• The type of cable construction used depends on the performance
requirements of the system and both the economic and
environmental constraints.
Types of optical fibers
1. Based on material
• Plastic core with plastic cladding
• Plastic core with glass cladding
• Glass core with glass cladding
2. Based on mode of transmission
• Single mode fiber
• Multimode fiber
3. Index profile
• Step-index fiber
• Graded index fiber
1. Based on material
1. Plastic core with plastic cladding
• Same material so it is easy in production
• Less expensive and easy to install
• Mostly use in short distance and have capability of 6Mbps
2. Glass core with plastic cladding (PCS)
• It is having low signal loss
• Less affected by radiation
• Suitable for military application
3. Glass core with glass cladding (SCS)
• Lower signal lost than PCS
• More susceptible in radiation areas and losses signal
2. Based on mode of transmission
1. Single mode fiber
•
•
•
•
Only one path for light to pass.
Very small diameter of core (7 to 10 μm)
Bandwidth up to 40Ghz.
Mostly used in long distance and low cost circuit like T.V. cable.
2. Multimode fiber
• Light takes more than one path to travel
• Core is having diameter of 20 to 100μm.
• Usually used for medium distance and high bandwidth.
3. Index profile
1. Step index fiber
• Uniform reflective index of core.
• Core have bigger refractive index than cladding.
• Graph of radial distance vs. refractive index is seems like a step-index fiber.
2. Graded index fibre
• Core of graded index fibre is non-uniform.
3. Refractive index
• Refractive index is highest at canter and decrease till end of core.
Connector and Splice Loss Mechanisms
Fiber Optic Connectors Types
Fiber Optic Connectors Types
• LC Connector: LC fiber connector provides a fully proof design and small size perfect for high density applications. It is available in
simplex and duplex versions. And LC connector is featured with a 1.25mm zirconia ferrule. It can improve the density of optical
fiber connector in the optical fiber distribution frame. Otherwise, it's a standard ceramic ferrule connector, easily terminated with
any adhesive.
• SC Connector: SC fiber connector is a snap-in connector with a 2.5mm ferrule that is widely used for its excellent performance.
The end face of the pin is used more PC or APC model grinding method. Their ceramic ferrules provide accurate alignment. Typical
matched SC fiber connectors are rated for 1000 mating cycles. SC connector features with low price, involve loss small ripple, and
high compressive strength.
• MPO/MTP Connector: The MPO connector is the industry acronym for "Multi-fiber Push On", with push-on insertion release
mechanism, provides consistent and repeatable interconnections and available with 8, 12, or 24 fibers. MTP® is a trademark of US
Conec for MPO connector. The MTP/MPO connector is manufactured specifically for a multifiber ribbon cable.
• FC Connector: FC connector was originally developed by NTT, Japan. FC is short for FERRULE CONNECTOR. It also uses a 2.5 mm
ferrule, its external strengthening way is to use metal sleeve, fastening way as the turnbuckle. FC connectors are constructed with
a metal housing and are nickel-plated. This kind of connector is simple in structure, convenient operation.
• ST Connector: ST connector has a bayonet mount and a long cylindrical 2.5mm ceramic (usually) or polymer ferrule to hold the
fiber. Most ferrules are ceramic, but some are metal or plastic. ST connectors are constructed with a metal housing and are nickelplated, can be inserted into and removed from a fiber-optic cable both quickly and easily.
• MT-RJ Connector: MT-RJ is a duplex connector used with single-mode and multimode fiber optic cables. It uses pins for alignment
and has male and female versions. MT-RJ connectors are constructed with a plastic housing and provide for accurate alignment via
their metal guide pins and plastic ferrules. The typical insertion loss for matched MT-RJ connectors is 0.25dB for SMF and 0.35 dB
for MMF.
Fiber Optic Connectors Types
• MU Connector: MU connector looks like a miniature SC with a 1.25mm ferrule, with a simple push-pull design and compact
miniature body. It is used for compact multiple optical connectors and self-retentive mechanism for backplane applications. MU
connectors are the optical connectors which miniaturized and were advanced the density application and performance.
• DIN Connector: DIN is an abbreviation for Deutsches Institut für Normung or German Institute for Standardization, which is a
German manufacturing industry standards group. DIN connector encompasses several types of cables that plug into an interface to
connect devices. It is round, with pins arranged in a circular pattern. Typically, a full-sized DIN connector has three to 14 pins with a
diameter of 13.2 millimeters. This type of connector was used widely for PC keyboards, MIDI instruments, and other specialized
equipment.
• E2000 Connector: E2000 fiber optic connector has a push-pull coupling mechanism, with an automatic metal shutter in the
connector as dust and laser beam protection. One-piece design for easy and quick termination, used for high safety and high
power applications. E2000 connector available for Singlemode PC, APC and Multimode PC.
• SMA Connector: Amphenol developed the SMA from the "Subminiature A" hence SMA, microwave connector. The model 905 had
a machined ferrule exactly 1/8 inch in diameter that mated in a machined adapter. When the adapters were not precise enough
for better fibers, a necked-down ferrule that mated with a Delrin adapter for better insertion loss performance. These connectors
are still in use on some military and industrial systems.
• D4 Connector: D4 connector was probably the first connector to use ceramic or hybrid ceramic/stainless steel ferrules. It's keyed
and spring loaded, the ferrule has a 2.0mm diameter ferrule. D4 connectors have a high-performance threading mounting system
and a keyed body for repeatability and intermateability.
A laser bouncing down an acrylicrod, illustrating the total internal reflection of light in a
multi-mode optical fiber.
https://en.wikipedia.org/wiki/Optical_fiber
Topics
1.
2.
3.
4.
Wired access networks [4]
1.1 Evolution of the public switched telecommunication network (PSTN)
1.2 Digital subscriber loop (DSL) standards and services
Wireless access networks [15 h]
2.1 Wireless channel characteristics
2.2 Fixed and mobile wireless access systems
2.3 Evolution of cellular systems to mobile broadband
2.4 Wireless broadband networks
2.5 Wireless Local Area Networks (LANs) and Personal Area Networks (PANs)
Optical communications and access networks [7 h]
3.1 Fundamentals of optical communications systems
3.2 Optical access networks; configurations and capabilities
Broadcast networks [4 h]
4.1 Evolution of broadcasting from analog to digital
4.2 Digital audio and video broadcasting; systems and standards
Thank you