光纤通信第一章(2012)
相关主题
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
Information: voice, video data
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 15
A typical telephone system
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 16
Loss
Gain
Amplification & Noise
Dispersion
Distortion
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 24
Pulse-code modulation(PCM) technique
2012年2月27日4时18分
Chapter 1
2012年2月27日4时18分
22
2 Why go digital?
Analog (continuous) Time
Digital (discrete) 1 0 1 0 1 Time
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 23
Cause
Effect Attenuation
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 13
The electron volt (eV) is another useful unit for analysis of fiber optic systems. The electron volt is defined as the energy acquired by an electron
2012年2月27日4时18分
21
From 29th ICCNC
1987年9月20日,在德国卡尔斯鲁厄大学教授维纳· 措恩的帮 助下,中国首次接入国际互联网.当天,维纳· 措恩教授和中国互联 网先驱王运丰教授联手起草了中国第一封跨国电子邮件,从北京 成功发往德国的卡尔斯鲁厄.这标志着中国跨出了走向互联网时 代的第一步.
Most of the frequencies in fiber optic systems are
In the Infrared.
Wavelength and frequency are related by:
v f
In free space, v = c = 3 x108 m/s
(1.3)
Chapter 1
By QianSheng, HDU
Page 17
★ Telecommunications: point to point systems and networks
networks
Point to point system
Nodes
Transmitter Receiver
2 1
3 4
• 《光纤通信》，Gerd Keiser，电子工业出版 社
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 3
Introduction:
• Nature of light
• Telecommunications
• A Fiber-Optic Communications System: The Basic Blocks
Information
Information Channel
Information
N
5
Link
Station
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 18
★Information- carrying capacity
1 Why produce more information?
•Light is an electromagnetic wave that satisfies Maxwell’s Equations. •The electromagnetic spectrum is a range of frequencies classified into groups.
Page 5
Information Era: We need information
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 19
Mbps
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 20
From 29th ICCNC
• A Look Back and a Glance Ahead
• Advantages of Glass Fibers
• Applications of Fiber Systems
• Some numbers and units
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 4
3 108 m / s 14 f 3.53 10 Hz 6 0.85 10 m c
The period of oscillation T is defined as the time it takes for the wave to complete one cycle. The period for the frequency in the preceding example is then
= 0.8 m? Answer
m 3 10 c s W p h 6.626 1034 J s 6 0.8 10 m J 19 W p 2.48 10 photon
8
W Pt 106 1 106 Joules W 106 J 4.03 1012 photons W p 2.48 1019 J photon
photon has energy:
W p hf h
c
(1.4)
h = 6.626 x 10-34 J s (Planck’s constant) Shorter wavelength (higher frequency) waves have greater photon energy.
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 12
Example: How many photons are delivered each second
for a wave with average power P = 1W at wavelength
accelerated across a 1 volt potential difference. The
conversion between electron volts and joules is:
1 eV = 1.6 x 10-19 J
The 0.8 m photon has an energy of: (2.48/1.6) = 1.55 eV
Transmitter
Message Origin Modulator
Receiver
Destination Processor
Electric Domain Carrier Source Coupler
Detector
Optic Domain
Channel
Coupler
2012年2月27日4时18分
The major operation regions (windows) are: Wavelength Window
0.8-0.9 m
~1.300 m
First Window
Second Window
~1.550 m
~1.600 m
Third Window
Fourth Window
2012年2月27日4时18分
Electric
phone
Radio TV
AM无线电 同轴电缆 双铰线
FM无线电
micro wave
卫星/微波
infra red
Visible light
光纤
107
106
105
104
103
102
101
100
10-1
10-2
10-3
10-4
10-5
10-6
Wave length（m）
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 7
where v is the velocity of the wave in the medium.
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 8
Example: If is 0.85 m, find the frequency. In this example the medium is not specified, so let us assume that the medium is free space.
Chapter 1
By QianSheng, HDU
Page 10
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 11
1.3.2
Particle Nature of Light Light is made up particles called photons. Each
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 6
★ The spectrum of OFC
101 102 103 104 105 106 107 108 109 1010 1011 1012 1013 1014 1015
1 1 14 T 0.28 10 s 14 f 3.53 10 Hz
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 9
Fiber optic systems must have low loss. For
glass low loss occurs at several wavelengths.
◆ Nature of Light
Sometimes light behaves as a wave and sometimes light behaves as a particle. We will look at both
behaviors.
1.3.1
wenku.baidu.com
Wave Nature of Light
光纤通信 Fiber Optic Communications
联系方式
姓 名： 钱胜 Email： hiqian@126.com Handset: 13777455099 办公地点：第一教研楼北楼428光纤通信网实验室
2012年2月27日4时18分
2
Reference
• 《光纤通信第五版（英文版）》, J C Palais, 电子工业出版社（教材）
By QianSheng, HDU
Page 25
Digitizing Steps
1) Pick the highest frequency: fu = 4 kHz for voice 2) Sample at twice the highest frequency
yielding: :
Sampling Rate = 2fu = 8000 samples/second
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 14
◆ Telecommunications
★ What It is
Tele-over a distance; communicationsexchange of information; Telecommunications: exchange of information over a distance using some type of equipment
• Fiber-Optic Communications Technology, Djafar K. Mynbaev, Lowell L. Scheiner eds., Pearson Education, Inc., 2001（教材） • 《光纤通信技术》, Djafar K. Mynbaev, 徐功 权等译, 机械工业出版社
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 15
A typical telephone system
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 16
Loss
Gain
Amplification & Noise
Dispersion
Distortion
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 24
Pulse-code modulation(PCM) technique
2012年2月27日4时18分
Chapter 1
2012年2月27日4时18分
22
2 Why go digital?
Analog (continuous) Time
Digital (discrete) 1 0 1 0 1 Time
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 23
Cause
Effect Attenuation
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 13
The electron volt (eV) is another useful unit for analysis of fiber optic systems. The electron volt is defined as the energy acquired by an electron
2012年2月27日4时18分
21
From 29th ICCNC
1987年9月20日,在德国卡尔斯鲁厄大学教授维纳· 措恩的帮 助下,中国首次接入国际互联网.当天,维纳· 措恩教授和中国互联 网先驱王运丰教授联手起草了中国第一封跨国电子邮件,从北京 成功发往德国的卡尔斯鲁厄.这标志着中国跨出了走向互联网时 代的第一步.
Most of the frequencies in fiber optic systems are
In the Infrared.
Wavelength and frequency are related by:
v f
In free space, v = c = 3 x108 m/s
(1.3)
Chapter 1
By QianSheng, HDU
Page 17
★ Telecommunications: point to point systems and networks
networks
Point to point system
Nodes
Transmitter Receiver
2 1
3 4
• 《光纤通信》，Gerd Keiser，电子工业出版 社
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 3
Introduction:
• Nature of light
• Telecommunications
• A Fiber-Optic Communications System: The Basic Blocks
Information
Information Channel
Information
N
5
Link
Station
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 18
★Information- carrying capacity
1 Why produce more information?
•Light is an electromagnetic wave that satisfies Maxwell’s Equations. •The electromagnetic spectrum is a range of frequencies classified into groups.
Page 5
Information Era: We need information
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 19
Mbps
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 20
From 29th ICCNC
• A Look Back and a Glance Ahead
• Advantages of Glass Fibers
• Applications of Fiber Systems
• Some numbers and units
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 4
3 108 m / s 14 f 3.53 10 Hz 6 0.85 10 m c
The period of oscillation T is defined as the time it takes for the wave to complete one cycle. The period for the frequency in the preceding example is then
= 0.8 m? Answer
m 3 10 c s W p h 6.626 1034 J s 6 0.8 10 m J 19 W p 2.48 10 photon
8
W Pt 106 1 106 Joules W 106 J 4.03 1012 photons W p 2.48 1019 J photon
photon has energy:
W p hf h
c
(1.4)
h = 6.626 x 10-34 J s (Planck’s constant) Shorter wavelength (higher frequency) waves have greater photon energy.
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 12
Example: How many photons are delivered each second
for a wave with average power P = 1W at wavelength
accelerated across a 1 volt potential difference. The
conversion between electron volts and joules is:
1 eV = 1.6 x 10-19 J
The 0.8 m photon has an energy of: (2.48/1.6) = 1.55 eV
Transmitter
Message Origin Modulator
Receiver
Destination Processor
Electric Domain Carrier Source Coupler
Detector
Optic Domain
Channel
Coupler
2012年2月27日4时18分
The major operation regions (windows) are: Wavelength Window
0.8-0.9 m
~1.300 m
First Window
Second Window
~1.550 m
~1.600 m
Third Window
Fourth Window
2012年2月27日4时18分
Electric
phone
Radio TV
AM无线电 同轴电缆 双铰线
FM无线电
micro wave
卫星/微波
infra red
Visible light
光纤
107
106
105
104
103
102
101
100
10-1
10-2
10-3
10-4
10-5
10-6
Wave length（m）
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 7
where v is the velocity of the wave in the medium.
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 8
Example: If is 0.85 m, find the frequency. In this example the medium is not specified, so let us assume that the medium is free space.
Chapter 1
By QianSheng, HDU
Page 10
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 11
1.3.2
Particle Nature of Light Light is made up particles called photons. Each
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 6
★ The spectrum of OFC
101 102 103 104 105 106 107 108 109 1010 1011 1012 1013 1014 1015
1 1 14 T 0.28 10 s 14 f 3.53 10 Hz
2012年2月27日4时18分 Chapter 1 By QianSheng, HDU Page 9
Fiber optic systems must have low loss. For
glass low loss occurs at several wavelengths.
◆ Nature of Light
Sometimes light behaves as a wave and sometimes light behaves as a particle. We will look at both
behaviors.
1.3.1
wenku.baidu.com
Wave Nature of Light
光纤通信 Fiber Optic Communications
联系方式
姓 名： 钱胜 Email： hiqian@126.com Handset: 13777455099 办公地点：第一教研楼北楼428光纤通信网实验室
2012年2月27日4时18分
2
Reference
• 《光纤通信第五版（英文版）》, J C Palais, 电子工业出版社（教材）
By QianSheng, HDU
Page 25
Digitizing Steps
1) Pick the highest frequency: fu = 4 kHz for voice 2) Sample at twice the highest frequency
yielding: :
Sampling Rate = 2fu = 8000 samples/second
2012年2月27日4时18分
Chapter 1
By QianSheng, HDU
Page 14
◆ Telecommunications
★ What It is
Tele-over a distance; communicationsexchange of information; Telecommunications: exchange of information over a distance using some type of equipment
• Fiber-Optic Communications Technology, Djafar K. Mynbaev, Lowell L. Scheiner eds., Pearson Education, Inc., 2001（教材） • 《光纤通信技术》, Djafar K. Mynbaev, 徐功 权等译, 机械工业出版社