why optical fiber has large bandwidh?

EDAboard.com Forum Index -> Electronic Elementary Questions -> why optical fiber has large bandwidh?

Author

Message

suvendu

Joined: 10 Oct 2004
Posts: 442
Helped: 25

08 Jun 2005 7:09 why optical fiber has large bandwidh?

dear sir,
please tell me what r the reason that the optical fiber has large bandwidh?

IanP

Joined: 05 Oct 2004
Posts: 6490
Helped: 1542
Location: West Coast

08 Jun 2005 7:31 Re: why optical fiber has large bandwidh?

Cutting story short, optical (light) waves as a carrier wave provides an enormous potential bandwidth. Optical carriers are in the region of 10 to the power of 13 Hz to 10 to the power of 16 Hz, and that is for example three to six orders of magnitude higher than microwave frequencies.
But don't be tricked by this high carrier frequency. Check this explenation on real bandwidth in optical fibre: http://www.ott.co.uk/news/features/cablingworld_01_2003.htm
Regards,
IanP

comsians

Joined: 22 May 2005
Posts: 46
Helped: 1

10 Jun 2005 9:02 Re: why optical fiber has large bandwidh?

it is because of the two main reasons

Firstly
it has many optical light paths known as "Europian 1" or called "E1"

Each E1 has a capacity of 2MB for data sending

2ndly because the power losses of data or signal is less than compare to other mediums

Belsugului

Joined: 10 Mar 2005
Posts: 49
Helped: 1

10 Jun 2005 9:48 Re: why optical fiber has large bandwidh?

Hi

comsians wrote:

Quote:

it has many optical light paths known as "Europian 1" or called "E1"

That has nothing to do with the large badwidth.

the same is true for the second one:

Quote:

the power losses of data or signal is less than compare to other mediums

The first one is a hystorical thing, the first digital transmission was through E1 (T1 ine USA) where 32 time sharing channels (one channel for each voice) was used to be carried on the same medium (coax cable). In order to note through away the old stuff newer staff was made compatible with E1. Thus STM1 can transport 63 E1s.
The 2nd one is an additional advantage, that you do not need to have repeaters at every couple of kms in case of coax cable or 5-10 kms in case of microwave, but only 10-20 km at multimode fiber and 60-80 km in case of single mode fiber.

The answer to your question was given correctly by IanP

Belsugului

rfmw

Joined: 10 May 2001
Posts: 520
Helped: 38

10 Jun 2005 11:18 Re: why optical fiber has large bandwidh?

Anyone knows the maximal usable (theoretical) bandwidth of a single-mode optical fiber using all the "windows"? Is in not 50 THz?

electron_boy

Joined: 14 Nov 2004
Posts: 193
Helped: 18
Location: Chennai, India

11 Jun 2005 2:04 Re: why optical fiber has large bandwidh?

optical fibers have a large bandwidth bcoz the light b/w is nealy 10^13 -10^15 hz

power-twq

Joined: 10 Jun 2005
Posts: 374
Helped: 3

22 Jun 2005 15:15 Re: why optical fiber has large bandwidh?

because fiber's loss is very low.

best regards

suvendu wrote:

dear sir,
please tell me what r the reason that the optical fiber has large bandwidh?

Google
AdSense
Google Adsense

22 Jun 2005 15:15 Ads

userdce

Joined: 31 May 2005
Posts: 31
Helped: 1

22 Jun 2005 18:46 Re: why optical fiber has large bandwidh?

fiber's loss has nothng to do with bandwidth

unless only for particular frequency that loss is there

Lachezar

Joined: 16 Aug 2005
Posts: 4

09 Apr 2006 8:22 Re: why optical fiber has large bandwidh?

In Fiber optics ,the more important thing is "BITRATE PRODUCT" not the bit rate itself,meaning maximum bit rate times distance(BL).
The bandwith (GB/S)depends on many factors such as modal dispersion D,material dispersion (b2 and b3) ,wavelength, what kind of source you have
lazer or Led,gaussian pulse phase chirp ,nonlinear effects so on. To answer the question,you have to go through serios statistic equations and Fourier transforms(unless you have very simple case b3=0,chirp=0,single mode,Gaussian pulse).It is impossible to answer the questions without using heavy math accounting for all those thinks i said before.
"Fiber optics communication systems" by Govind Agrawal chapter3 explains it in detail

LT

El-Hadidy

Joined: 23 Feb 2006
Posts: 63
Helped: 1

01 May 2006 16:40 Re: why optical fiber has large bandwidh?

hello,

I suppose this occurs due to the fact that light has different characteristics than normal voltage or current.

Thanks

El-Hadidy

sabari

Joined: 02 Oct 2004
Posts: 66
Helped: 1

01 May 2006 19:53 why optical fiber has large bandwidh?

so many critical angles hence large bandwidth

jjohn

Joined: 17 Jun 2006
Posts: 275
Helped: 26

23 Jun 2006 17:02 why optical fiber has large bandwidh?

* Gambling, W. A., "The Rise and Rise of Optical Fibers", IEEE Journal on Selected Topics in Quantum Electronics, Vol. 6, No. 6, pp. 1084-1093, Nov./Dec. 2000
* Gowar, John, Optical Communication Systems, 2 ed., Prentice-Hall, Hempstead UK, 1993 (ISBN 0136387276)
* Hecht, Jeff, City of Light, The Story of Fiber Optics, Oxford University Press, New York, 1999 (ISBN 0195108183)
* Hecht, Jeff, Understanding Fiber Optics, 4th ed., Prentice-Hall, Upper Saddle River, NJ, USA 2002 (ISBN 0130278289)
* Nagel S. R., MacChesney J. B., Walker K. L., "An Overview of the Modified Chemical Vapor Deposition (MCVD) Process and Performance", IEEE Journal of Quantum Mechanics, Vol. QE-18, No. 4, April 1982
* Ramaswami, R., Sivarajan, K. N., Optical Networks: A Practical Perspective, Morgan Kaufmann Publishers, San Francisco, 1998 (ISBN 1558604456)

May be tried..

kkeiser
Guest

24 Jun 2006 6:40 why optical fiber has large bandwidh?

It is the properties of fibre (transporting media) provides the better bandwith.

tania_04

Joined: 13 Mar 2006
Posts: 14

29 Jun 2006 14:26 Re: why optical fiber has large bandwidh?

the idea behind using optical fibre was due to the fact that the bandwidth is large due to the high frequency of light waves and ofcourse the very low loss of the line

fatma1000

Joined: 30 Apr 2006
Posts: 373
Helped: 2

12 Jul 2006 12:12 Re: why optical fiber has large bandwidh?

i need a good material in optical netwarks please any one has any thig (books, software ....) please send it to me
regards

dkk

Joined: 06 Jun 2006
Posts: 121
Helped: 11

14 Jul 2006 12:33 Re: why optical fiber has large bandwidh?

fatma1000 wrote:

i need a good material in optical netwarks please any one has any thig (books, software ....) please send it to me
regards

-----------------------------------------------------------------------------------------------In addition to last book listed by JJohn above
few more books are available

1. Optical Communication Networks by Biswanath Mukherjee -1997
Publisher - McGraw Hill
(Perhaps another edition is published in 2000 by Kluwer)

2. WDM Optical networks:Concepts Design and Networks By C.RamaMurthy and Mohan Guruswami
Publisher:PHI - 2002
ISBN-81-203-2129-4

3.Optical WDM networks:Concepts and design Principles by Jun Zheng and Hussein T. Mouftah
Publisher John Wiley and Sons and IEEE Press

You can find out on this board if the link for these books available else partly you can also see on google book search
DKK

Added after 13 minutes:

(A)Is the complete theoretical bandwidth is usable bandwidth in case of optical fiber? If not what are the hurdles?

(B) Supposing the total banbdwidth avaible theoretically is practically usable what will be scenario interms of data rate, no of channels or that signals that we can transmit at a given time?

mizel

Joined: 14 Jul 2006
Posts: 8
Helped: 3

14 Jul 2006 20:53 Re: why optical fiber has large bandwidh?

Also, remember there are real world constraints. In the real world frequencies that are close to eachother cannot be used in fiber and we are limited by the rate at which actual electronics can sample the data (we can't sample at the speed of light).

This may not be relevant in the theoretical bandwidth of fiber, but they are interesting points if you ever consider real world applications.

dkk

Joined: 06 Jun 2006
Posts: 121
Helped: 11

23 Jul 2006 8:02 Re: why optical fiber has large bandwidh?

fatma1000 wrote:

i need a good material in optical netwarks please any one has any thig (books, software ....) please send it to me
regards

In addition to the the books listed above, for indepth inside into OPTICAL NETWORKs one can go through following text

1. EMERGING OPTICAL NETWORK TECHNOLOGIES :Architectures, Protocols
and Performance
Edited by
KRISHNA M. SIVALINGAM
University of Maryland, Baltimore County
SURESH SUBRAMANIAM
George Washington University

2. Metropolitan Area WDM Networks: An AWG-Based Approach
Martin Maier
ISBN 1-4020-7574-X, 2003
http://www.wkap.nl/prod/b/1-4020-7574-X

3. Optical Networks: Architecture and Survivability
Hussein T. Mouftah and Pin-Han Ho
ISBN 1-4020-7196-5, 2002
http://www.wkap.nl/prod/b/1-4020-7196-5

4. WDM Mesh Networks: Management and Survivability
Hui Zang
ISBN 1-4020-7355-0, 2002
http://www.wkap.nl/prod/b/1-4020-7355-0
DKK

hshalaby

Joined: 10 Mar 2005
Posts: 6
Location: Egypt

01 Oct 2008 10:26 Re: why optical fiber has large bandwidh?

bandwidth is rouphly 1/10 of the carrier frequency.
Since the optical carrier frequency is in the range of 10^14 Hz, its bandwidth is high.

subharpe

Joined: 09 Jan 2008
Posts: 244
Helped: 34
Location: Bangalore,India

01 Oct 2008 18:44 Re: why optical fiber has large bandwidh?

It is beacuse of purely the properties of Silicon di Oxide or glass. If you find the attenuation constant α, the attenuation per unit length vs. wavelength of light plots for Sio2, you will find there are two local minima around at 1.3 and 1.55 µm and the 3db points about these two minima which add up to nearly 120THz in frequency. This gives the enormous bandwidth for optical fiber.

Also the actual attenuation is a function of the length of the fiber. Like normal amplifiers where gain bandwidth product is a figure of merit for the amplifier, for optical fibers the legth bandwidth product is a figure of merit.