HISTORY, INDIAN SMOKE COMMUNICATION...A BRIEF HISTORY OF F.O By 1964, a critical and theoretical specification was identified by Dr. Charles K. Kao for long-range communication devices,

K.S.OPENDAHULUAN

[email protected]

HISTORY, INDIAN SMOKE COMMUNICATION

A BRIEF HISTORY OF F.O

In 1880, Alexander Graham Bell patented an optical telephone system, which he called the Photophone. However, his earlier invention, the telephone, was more practical and took tangible shape.

The Photophone remained an experimental invention and never materialized.

BELL’S PHOTOPHONE


During the 1920s, John Logie Baird in England and Clarence W. Hansell in the United States patented the idea of using arrays of hollow pipes or transparent rods to transmit images for television or facsimile systems.

In 1954, Dutch scientist Abraham Van Heel and British scientist Harold H. Hopkins separately wrote papers on imaging bundles. Hopkins reported on imaging bundles of unclad fibers, whereas Van Heel reported on simple bundles of clad fibers. Van Heel covered a bare fiber with a transparent cladding of a lower refractive index.

This protected the fiber reflection surface from outside distortion and greatly reduced interference between fibers.


Abraham Van Heel is also notable for another contribution. Stimulated by a conversation with the American optical physicist Brian O'Brien, Van Heel made the crucial innovation of cladding fiber-optic cables.

All earlier fibers developed were bare and lacked any form of cladding, with total internal reflection occurring at a glass-air interface. Abraham Van Heel covered a bare fiber or glass or plastic with a transparent cladding of lower refractive index. This protected the total reflection surface from contamination and greatly reduced cross talk between fibers.


By 1960, glass-clad fibers had attenuation of about 1 decibel (dB) per meter, fine for medical imaging, but much too high for communications.

In 1961, Elias Snitzer of American Optical published a theoretical description of a fiber with a core so small it could carry light with only one waveguide mode. Snitzer's proposal was acceptable for a medical instrument looking inside the human, but the fiber had a light loss of 1 dB per meter.

Communication devices needed to operate over much longer distances and required a light loss of no more than 10 or 20 dB per kilometer.


By 1964, a critical and theoretical specification was identified by Dr. Charles K. Kao for long-range communication devices, the 10 or 20 dB of light loss per kilometer standard. Dr. Kao also illustrated the need for a purer form of glass to help reduce light loss.

In the summer of 1970, one team of researchers began experimenting with fused silica, a material capable of extreme purity with a high melting point and a low refractive index.

Corning Glass researchers Robert Maurer, Donald Keck, and Peter Schultz invented fiber-optic wire or "optical waveguide fibers" (patent no. 3,711,262), which was capable of carrying 65,000 times more information than copper wire, through which information carried by a pattern of light waves could be decoded at a destination even a thousand miles away.


The team had solved the decibel-loss problem presented by Dr. Kao. The team had developed an SMF with loss of 17 dB/km at 633 nm by doping titanium into the fiber core.

By June of 1972, Robert Maurer, Donald Keck, and Peter Schultz invented multimode germanium-doped fiber with a loss of 4 dB per kilometer and much greater strength than titanium-doped fiber.

By 1973, John MacChesney developed a modified chemical vapor-deposition process for fiber manufacture at Bell Labs. This process spearheaded the commercial manufacture of fiber-optic cable.


In April 1977, General Telephone and Electronics tested and deployed the world's first live telephone traffic through a fiber-optic system running at 6 Mbps, in Long Beach, California.

They were soon followed by Bell in May 1977, with an optical telephone communication system installed in the downtown Chicago area, covering a distance of 1.5 miles (2.4 kilometers). Each optical-fiber pair carried the equivalent of 672 voice channels and was equivalent to a DS3 circuit.


Today more than 80 percent of the world's long-distance voice and data traffic is carried over optical-fiber cables.

Submarine Cable Map 2016 (www.telegeography.com)

OVERVIEW

ELECTROMAGNETIC SPECTRUM

Spektrum gelombang optik berada pada range 50

nm (ultraviolet) – 100 µm (far infrared).

Visible region berada pada band 400 – 700 nm.

Pada awal penggunaannya sistem optik

menggunakan sistem multiplex FDM/TDM, baru di

peretengahan 1990-an menggunakan WDM.

Relasi antara frekuensi dan panjang gelombang:

c = v.λ, dimanac = Cepat rambat cahayav = Frekuensiλ = Panjang gelombang

VISIBLE LIGHT SPECTRUM

1.5eV3eV 2.5eV 2eV

800nm

300nm

3.5eV4eV

BASIC NETWORK INFORMATION RATES

Boomingnya layanan seperti video on demand, home shopping, remote education, telemedicine, dan videoconferencing pada tahun 1990-an sebagai imbas dari booming nya industri Personal Computer (PC) disertai dengan tumbuhnya penggunaan internet, menyebabkan semakin tingginya kebutuhan bandwidth layanan untuk setiap pelanggan.


Type of services Data rate

Video on demand/ interactive TV 1,5 – 6 Mbps

Video games 1 – 2 Mbps

Remote education 1,5 – 3 Mbps

Electronic shopping 1,5 – 6 Mbps

Data transfer or telecommuting 1 – 3 Mbps

Videoconferencing 0,384 – 2 Mbps

Voice (single channel) 64 kbps


Untuk mengirimkan layanan-layanan tersebut dari satu user ke user lainnya, network provider (penyedia layanan) menggabungkan sinyal dari beberapa user yang berbeda dan kemudian mengirimkannya melalui single transmission line.

Metode ini dikenal dengan Time Division Multiplexing (TDM). N informasi yang saling independen, memiliki R bps, kemudian di interleaved secara elektris ke dalam single information stream yang beroperasi pada kecepatan yang lebih tinggi sebesar N x R bps.


Digital transmission hierarchy

Called Telephony or T-Networks

Uses Copper


Gambar di atas menunjukkan digital transmission hierarchy yang digunakan di jaringan telepon North America.

Bagian dasar hierarchy tsb adalah transmisi rate pda 1,544 Mbps, atau yang dikenal dengan T1 rate.

Angka tsb didapatkan dari perkalian 64 kbps dikalikan dengan 24 kanal suara, ditambah dengan Frame bits, maka menjadi 1,544 Mbps.

Untuk level2 diatasnya, signal pada input rate dikalikan dengan input lain dengan rate yang sama.

Tidak hanya dibatasi untuk kanal suara saja, sebagai contoh pada kanal T1, semua sinyal digital dengan rate 64 kbps dapat dibawa dengan 24 input kanal.


Sebagian besar aplikasi awal dari penggunaan fiber optik adalah untuk trunking kanal telepon, dimana merupakan digital link terdiri kanal suara sebesar 64 kbps yang ter-multipleks secara time-digital multiplex

Penggunaan awal kanal transmisi fiber optik dengan kapasitas tinggi pada 1980 –1990-an, service provider menyediakan standard signal format yang disebut dengan Synchronous Optical Network (SONET) di North America dan Synchronous Digital Hierarchy (SDH) di sebagian besar lain dunia (Eropa, Asia, dll).

Standar tersebut mendefinisikan synchronous frame structure untuk mengirimkan multiplexed digital traffic melalui kanal fiber optik.


North America

Other parts of the

world (Eropa,

Asia, dll)

EVOLUSI SISTEM FIBER OPTIK

Operating range of

optical fiber system


• Generasi pertama beroperasi di 850 nm dengan serat multimode dan bit rate 45 s.d. 140 Mbps dengan spasi repeater 10 km.

• Berikutnya penggunaan serat Single Mode memungkinkan bit rate 155 Mbps, 622 Mbps, hingga 2,5 Gbps dengan spasi repeater 40 km.

• Sistem 1550 nm memberikan kapasitas sampai 10 Gbps dengan spasi repeater hingga 90 km pada 2,5 Gbps.

FIBER OPTIC CABLE (MULTIMODE & SINGLE MODE)

Low loss (Attenuation)

FIRST GENERATION FO SYSTEM

Purpose

• Eliminate repeaters in T-1 systems used in inter-office trunk lines

Technology

• 0.8 µm GaAs semiconductor lasers

• Multimode silica fibers

Limitations

• Fiber attenuation

• Intermodal dispersion

Deployed since 1974

SECOND GENERATION FO SYSTEM

Opportunity

• Development of low-attenuation fiber (removal of H2O and other impurities)

• Eliminate repeaters in long-distance lines

Technology

• 1.3 µm multi-mode semiconductor lasers

• Single-mode, low-attenuation silica fibers

• DS-3 signal: 28 multiplexed DS-1 signals carried at 44.736 Mbits/s

Limitation

• Fiber attenuation (repeater spacing ≈ 6 km)

Deployed since 1978

THIRD GENERATION FO SYSTEM

Opportunity

• Deregulation of long-distance market

Technology

• 1.55 µm single-mode semiconductor lasers

• Single-mode, low-attenuation silica fibers

• OC-48 signal: 810 multiplexed 64-kb/s voice channels carried at 2.488 Gbits/s

Limitations

• Fiber attenuation (repeater spacing ≈ 40 km)

• Fiber dispersion

Deployed since 1982

FOURTH GENERATION FO SYSTEM

Opportunity

• Development of erbium-doped fiber amplifiers (EDFA)

Technology (deployment began in 1994)

• 1.55 µm single-mode, narrow-band semiconductor lasers

• Single-mode, low-attenuation, dispersion-shifted silica fibers

• Wavelength-division multiplexing of 2.5 Gb/s or 10 Gb/s signals

Nonlinear effects limit the following system parameters

• Signal launch power

• WDM channel separation

• Maximum number of WDM channels per fiber

ELEMEN-ELEMEN TRANSMISI FIBER OPTIK

FIBER OPTIK

STRUKTUR FIBER OPTIK


1. Core

Merupakan tempat merambatnya cahaya dari satu ujung ke ujung lainnya(carries the light signals). Terbuat dari bahan silica dan bahan tambahan.

Diameter core:

Single mode fiber (SMF) : ± 10 µm

Multimode step index : ± 50 µm

Multimode graded index : ± 50 µm


2. Cladding

Berfungsi sebagai cermin, yakni memantulkan cahaya agar dapat merambat keujung lainnya (keeps the light in the core). Terbuat dari pure silica.

Terbuat dari bahan kuarsa atau silika dengan nilai indeks bias lebih kecil dariCore.

Merupakan selubung dari Core.

Hubungan indeks bias antara Core dan cladding akan mempengaruhiperambatan cahaya pada Core ( berpengaruh terhadap besarnya sudut Kritis).

Diameter cladding:

SMF, MMF : ± 125 µm


3. Coating (jacket)

Berfungsi sebagai pelindung mekanis core dan cladding (Protects the glass). Terbuat dari bahan plastik.

Diameter coating:

NEXT

Hukum Snellius

NA

SMF, MMF

Documents

HISTORY, INDIAN SMOKE COMMUNICATION...A BRIEF HISTORY OF F.O By 1964, a critical and theoretical specification was identified by Dr. Charles K. Kao for long-range communication devices,