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Spectrum Of Erbium Doped Fiber Amplifier Computer Science Essay

Optical Amplifier can decrease the effects of scattering and fading leting improved public presentation of long-haul optical systems. With the demand for longer transmittal lengths, optical amplifiers have become an indispensable constituent inA long-haul fiber ocular systems.

In optical fibre web, amplifiers are used to renew an optical signal, amplify and so retransmitting an optical signal. In long-haul optical systems, the there are many amplifiers are needed to forestall the end product of signal earnestly attenuated. In order cut down the cost ; the sum of amplifiers can be reduced by addition the spacing between them.

Current spacing of Erbium Doped Fiber Amplifier is in the scope of 80km to 100km.

The addition spectrum of Erbium Doped Fiber Amplifier is non inherently level. For individual channel systems, the addition fluctuation is non a job. However, in optical fibre web the channel increases, the transmittal job arises. The addition two-dimensionality is importance for erbium-doped fibre amplifiers ‘ ( EDFA ‘s ) wavelength division multiplexing ( WDM ) which is of import technique for long haul optical transmittal nexus system.

They typically present addition peaking at about 1530 nanometer and the utile addition bandwidth may be reduced to less than 10 nanometers.

There are one major job of EDFA which is amplified self-generated emanation ( ASE ) generated by stimulation emanation during elaboration of input signals. The amplified self-generated emanation ( ASE ) is background noise. This noise signal being amplified with the input signal when after go through another amplifier.

The end product signal power additions will diminish the spacing of the EDFA. The end product signal power can be optimized by maximise the addition.

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Furthermore, the addition is the parametric quantity of the doping concentration and doping profile of the Er doped fibre, length of the fibre, windows wavelength of input signal, input powers and the pump power. But the length of the fibre is the spacing of repeater where is one of the undertaking result of this undertaking.

OptiSystem is a design and simulation package for fibre optics application. OptiSystem enables users to simulate/design following coevals optical webs, current optical webs, SONET/SDH pealing webs, amplifiers, receiving systems, senders. This package has many analysis tools oculus diagrams, BER, Q-Factor, Signal chirp, polarisation province, configuration diagrams, signal power, addition, Noise Figure, OSNR, information proctors, study coevals, and more.

Aims of Undertaking

This undertaking simulates and optimizes the public presentation parametric quantities of EDFA. The aims of this undertaking are outlined as below:

to increase end product signal power.

to flatten the addition of Erbium Doped Fiber Amplifier.

to cut down the Amplified Spontaneous Emission ( ASE ) of Erbium Doped Fiber Amplifier.

Problem Statement

In order to hold a high capacity transmittal system, there are several ways such as by utilizing wave-dense multiplexing ( WDM ) technique, increase the power of end product transmittal system, cut down the losingss in transmittal system and etc. By addition the figure of optical amplifier in long draw transmittal system is able to increase the end product power of transmittal system but this will increase the costs. Therefore, the better solution is to optimise the public presentation of optical amplifier.

The end product signal power is chiefly affected by addition of the EDFA. The addition is affected by many factors which are the doping concentration and doping profile of the Er doped fibre, length of the fibre, wavelength Windowss input signal, input powers and the pump power. The addition the input signal power surely will increase the end product signal power but the addition decreases. The wavelength of input signal of EDFA can be in 1530nm to 1565nm ( C-band ) or 1570nm to 1605nm ( L-band ) . The addition of C set is greater than L-band but the soaking up is besides big.

Amplified Spontaneous Emission Noise ( ASE ) of Erbium Doped Fiber Amplifier ( EDFA ) amplified together with the input signal. To obtain high end product power, the Erbium Doped Fiber Amplifier ( EDFA ) need high optical pump power and high inversion. Therefore, the higher inversion applied in EDFA, the higher the ASE noise. In the others word, Noise Figure will increase with the addition of EDFA.

Gain two-dimensionality is a map of inversion degree. Typically 40 % to 60 % inversion leads to broadest addition with last rippling. The addition at the L set is flatter than C set but the C set has lower addition. The usage of addition flattening filter can be a solution of addition two-dimensionality job but it will diminish end product signal power.

Scope of the Undertaking

This undertaking merely involves the optimisation of Erbium Doped Fiber Amplifier. The other types of optical fibre amplifiers are non involved. This undertaking focuses on the simulation utilizing package optisystem and does non affect any hardware. In add-on, decrease of the noise covered in this undertaking which covers Amplified Spontaneous Emission noise merely and does non covers any others ‘ noises such as thermic noise, human noise and etc. The optimisation of Erbium Doped Fiber end product signal power is included in this undertaking. This undertaking is focus on the long draw transmittal system where utilizing the individual manner fibre merely.

Undertaking Outcomes

In the terminal, The Erbium Doped Fiber Amplifier simulated with increased addition two-dimensionality. The Erbium Doped Fiber Amplifier simulated with high end product power and the spacing of repeaters were increased but the Erbium Doped Fiber Amplifier simulated have little sum of Amplified Spontaneous Emission.

Methodology

The basic information of optical fibre amplifier was obtained from the mention book and from internet beginnings. The information obtained is the basic constellation of optical amplifier in optical transmittal nexus, advantages and disadvantages of Erbium Doped Fiber Amplifier, the Amplified Spontaneous Emission Noise ( ASE ) and etc. Second methods of informations and information aggregations are from diary, magazine and mention books. The information and information is more progress such as the consequence of ASE noise, analysis of addition two-dimensionality of EDFA, the relationship between ASE noise and pump power and etc.

Thesis Structure

Chapter 1: In this chapter, the aims of the undertaking were introduced. In overview of the undertaking will present the basic thought of undertaking and some basic cognition related in this undertaking. The jobs and the expected result of this undertaking were besides stated.

Chapter 2: In this chapter, the research to play down related of this undertaking will be discussed. The construct construction of future work of this undertaking will be come out by literature reappraisal. How to work out the job stated in chapter 1 by using the correct theory were explained in inside informations.

Chapter 3: The processs of solution to the stated jobs in this undertaking were explained in this chapter. The processs that have been chose and the pick of processs have to province in this chapter. The jobs of jobs ‘ analysis and aggregation of were included.

Chapter 4: The consequences of this undertaking were show in this chapter. The consequences include simulation of the transmittal nexus and analysis of the public presentation transmittal nexus. The treatments of the consequences besides have to include.

Chapter 5: The aim, discourse the findings and conclude the restriction of this undertaking are being justified in this chapter. Some recommendations on how to better the undertaking were discuss at the terminal of this chapter.

Chapter 2

LITERATURE REVIEW

This chapter discussed all the utile theory and informations about this undertaking. The literature reappraisal was mentioning the diary, article, mention books and informations sheet. These beginnings were collected from the library, cyberspace and IEEE library web site.

2.1 Introduction

Optical fibre has three chief types of belongings which are scattering, soaking up, and dispersing. These belongingss have cause fading, power losingss, end product power lessening where bring disadvantages to the long draw transmittal. Dispersion occurs when the visible radiation going down a fiber ocular overseas telegram “ spreads out, ” becomes longer in wavelength and finally dissipates. Absorption is ensuing by the drosss such as hydroxyl ions where will do the optical power dissipated as heat power. Scattering is another major mechanism of fading in optical fibre. It happens when the light alteration way or diffuse where caused by the light striking the little atoms or the in-homogeneity of conveying stuff.

Attenuation, a decrease in the familial power, has long been a job for the fibre optics community. The addition in informations loss over the length of a fibre has hindered widespread usage of fibre as a agency of communicating. However, research workers have categorized three chief beginnings of this loss: soaking up, sprinkling, and, though it is non normally studied in this class, scattering.

With the demand for longer transmittal lengths, optical amplifiers have become an indispensable constituent in long-haul fibre ocular systems. An optical amplifier is a device that amplifies an optical signal straight, without the demand to first change over it to an electrical signal. By Optical amplifier, the capacity of optical transmittal system is additions. Stimulated emanation in the amplifier ‘s addition medium will do elaboration of incoming visible radiation.

Semiconductor optical amplifiers ( SOAs ) , Er doped fiber amplifiers ( EDFAs ) , and Raman optical amplifiers lessen the effects of scattering and fading leting improved public presentation of long-haul optical systems. Optical amplifier Semiconductor optical amplifiers ( SOAs ) , Er doped fiber amplifiers ( EDFAs ) , and Raman optical amplifiers lessen the effects of scattering and fading leting improved public presentation of long-haul optical systems.

There are many transmittal Windowss ( wavelength sets ) where show at table 2.1. Each consequence that contributes to fading and scattering depends on the optical wavelength. Raman Amplifier have broadest set among the optical amplifiers where from O set to U set. Whereas Er doped fiber amplifiers largely work on C set or L set.

Set

Description

Wavelength Range

O set

original

1260 to 1360 nanometer

Tocopherol set

extended

1360 to 1460 nanometer

S set

short wavelengths

1460 to 1530 nanometer

C set

conventional ( “ Er window ” )

1530 to 1565 nanometer

L set

long wavelengths

1565 to 1625 nanometer

U set

Ultra-Long wavelengths

1625 to 1675 nanometer

Table 2.1 transmittal Windowss ( wavelength sets ) [ 1 ] .

2.2 Erbium Doped Fiber Amplifier

The innovation of the EDFA in the late 1880ss was one of the major events in the history of optical communications. It provided new life to the optical fiber transmittal window centred at 1550 nanometer and the attendant research into engineerings that allow high bit-rate transmittal over long distances. Erbium Doped Fiber Amplifier has nucleuss doped with atoms of an component that light from an external optical maser can excite to a province in which stimulated emanation can happen. Pump visible radiation from the external optical maser steadily illuminates one or both terminals of the fibre and is guided along the fibre length to excite the atoms in the nucleus.

The basic constellation for integrating the EDFA in an optical fiber nexus is shown in Figure 2.1. The signals and pump are combined through a WDM coupling and launched into an erbium-doped fiber. The amplified end product signals can be transmitted through 60-100km before farther elaboration is required.

Figure 2.1 Basic constellation for the incorporation of an EDFA in an optical fibre nexus.

The Figure 2.2 shows elaboration in the erbium-doped fibre amplifier. Small measures of Er are present in the fibre nucleus. When light excites the Er atoms, a weak signal in the Er elaboration set guided along the fibre nucleus stimulates emanation, and the signal grows in strength along the length of the fibre.

Figure 2.2 Amplification in an erbium-doped fibre amplifier [ 1 ] .

An EDFA is an optical fibre of which the nucleus is doped with the rare-earth component Erbium. By exciting the Erbium ions to higher energy degrees, we can accomplish elaboration of signals at wavelengths interesting for optical communicating, i.e. around 1550 nanometer. The energy degrees are non really crisp, which leads to a comparatively big addition bandwidth. In order to excite the Er3+-ions, we send a beam of visible radiation, which we call the pump, into the fibre. If the pump is at wavelength 980 nanometer, Er3+ will lift from the land province L1 to the higher L3, as illustrated in Figure 2.3. However, the ions will quickly disintegrate to energy degree L2 without bring forthing photons. The life-time in L3 is about 1 I?s. Pumping with 1480 nanometer visible radiation will excite the ions straight to province L2. Relaxation from L2 to L1 will happen after about 10 MSs, bring forthing photons in the wavelength set 1520-1570 nanometer. This is called self-generated emanation.

Figure 2.3 Energy degrees of Er3+ ions in EDFA [ 3 ] .

Spontaneous emanation has no correlativity with the signal, but is distributed over the full bandwidth of the L2-L1 passage and can go in backward every bit good as forward extension way. Hence, it is noise. Obviously, outcome 2 is the coveted behavior of an amplifier and can be achieved by pumping the fibre until population inversion occurs: when the figure of ions in province L2 exceeds the figure of ions in the land province, the chance of result 2 is higher than that of 1 and 3.

However, self-generated emanation is ever present and will, like the signal, experience elaboration as it propagates through the fibre. This is termed amplified self-generated emanation or ASE. While the ASE degree is independent of the signal at low signal powers, high signal powers will consume the population inversion faster than the pump can keep it, and the ASE degree additions.

The pump visible radiation must be specific wavelengths in order to excite emanation from the Er atoms. Standard pumps are semiconductor optical masers that emit 980 or 1480 nanometer. Each wavelength has its ain advantages.

Figure 2.4 shows the overall construction of an erbium-fiber amplifier, excluding the inside informations inside the fibre. The input signal enters from the left ( in this illustration, a individual optical channel at 1550nm ) . It passes through an optical isolator, which blocks visible radiation from traveling back toward the light beginning, and filter, which transmits the signal wavelength but blocks the wavelength of the pump optical maser. Then the signal enters the erbium-doped amplifying fibre. Light from the pump optical maser is coupled into the other terminal of the erbium-doped fibre to excite Er atoms, which amplify the signal passing through the cringle of fibre. Then the amplified signal is separated from the pump at a wavelength-selective coupling on the right, and exits through another optical isolator into the following leg of the fiberoptic system.

The pump visible radiation must be specific wavelengths in order to excite emanation from the Er atoms. Standard pumps are semiconductor optical masers that emit 980 or 1480 nanometer. Each wavelength has its ain advantages.

Figure 2.4 Erbium doped fiber amplifier [ 1 ] .

It work typically works at wavelength from 1530nm to 1605nm, where silicon oxide fibres have their lowest loss. Over last decennary long draw system has evolved from individual channel low spot rate to multichannel system at informations rate every bit high as 40 Gigabits. Therefore, the Er doped fiber amplifier is widely used in long haul optical transmittal nexus [ 1 ] [ 3 ] . The elaboration set of EDFA is 1530 to 1610nm and the pump length is 980nm or 1480nm [ 4 ] . EDFA has 20 to 30dB addition where is considered high for long haul transmittal system. The pump power of the EDFA is low where from 10mW to 5W whereas one of the celebrated optical amplifiers which is Raman amplifier need 500mW to 5W pump power to execute elaboration. The Noise Figure of the EDFA is 3.5 to 6.5dB [ 4 ] .

2.3 Gain of Erbium Doped Fiber Amplifier

The addition of an EDFA is the ratio of the end product signal power ( Pout ) to the input signal power ( Pin ) where the equation is:

The addition of the amplifier is depends on the doping concentration and doping profile of the Er doped fibre, length of the fibre, windows wavelength of input signal, input powers and the pump power. Thus the parametric quantities to optimise the Gain of EDFA were shown as above.

Figure 2.5 Addition and soaking up in typical erbium-doped fibre [ 1 ]

There are two set input wavelengths for the EDFA which are C set ( 1530 to 1565 nanometer ) and L set ( 1565 to 1625nm ) [ 1 ] . For C set, the addition is high but it can utilize several metres of optical fibre merely. From the Figure 2.5, the addition is high at short wavelengths, but it is offset by high soaking up. For L set, the addition is non big but the soaking up besides little. It can be use 30 metres or more of the optical fibre [ 1 ] [ 5 ] . Therefore, C set is non suited for long draw transmittal link whereas L set is suited but C set and L set can be used at the same time [ 2 ] .

Figure 2.6 Variation of addition with EDFA length for different values of pump powers. For a given pump power there is an optimal length for accomplishing maximal addition [ 1 ] .

Figure 2.7 Variation of addition with pump power for different lengths of Er doped fiber [ 1 ] .

The Figure 2.6 shows that the addition additions foremost by increasing the length of the doped fibre and so get down to diminish after reached upper limit for given input pump power [ 2 ] . This happens because as the pump propagates through the doped fiber it gets absorbed and therefore its power reduced. After propagating certain distance, its power is excessively little to make population inversion, and therefore after this length, the doped fibre would get down to absorb the signal instead than magnify it. The Figure 2.7 shows the addition additions with pump power for a given length of the doped fibre [ 2 ] . The pump power additions and the population inversion created more and more in the certain length of doped fiber given.

2.4 Gain Flatness

One of the disadvantages of the EDFA is the addition is non inherently level but the addition two-dimensionality is importance for erbium-doped fibre amplifiers ‘ ( EDFA ‘s ) wavelength division multiplexing ( WDM ) which is of import technique for long haul optical transmittal nexus system. The form of the addition spectrum depends on the operating addition degree, or, in other words, on the population inversion [ 6 ] . The addition of the L set is flatter than addition of C set where can be observed at Figure 2.5 and Figure 2.8. The addition can be flattening by utilizing the addition flattening filter but this filter will diminish the end product signal power.

There are two classs of addition flattening techniques which are inactive and active. The filtering method is in class of passive. The disadvantages of the filtering method are increase the noise and cut down the end product power of EDFA [ 10 ] .

Figure 2.8 Calculated addition for C- set and L- set amplifier [ 1 ]

There is one of techniques is intercrossed of Optical Amplifier. Hybrid amplifier can be in series or parallel constellation. The series constellation of intercrossed two EDFA is shown as Figure 2.9 [ 8 ] . The parallel constellation of C-Band EDFA and L-Band Raman is shown as Figure 2.10 [ 9 ] .

Figure 2.9 Hybrid Series constellation [ 8 ]

Figure 2.10 Hybrid parallel constellations [ 9 ]

2.5 Amplified Spontaneous Emission

Optical amplifier is an linear device, it amplify any input noise that come with the input signal. The background noise called amplified self-generated emanation ( ASE ) besides generated. The ASE is generated by stimulation emanation during elaboration of input signal. The visible radiation that start stimulated emanation in a optical maser is emitted spontaneously when an aroused atom releases its extra energy without outside stimulation. A optical maser bounces this light back and Forth through the optical maser pit to magnify it by stimulated emanation. Fiber amplifiers lack resonating chamber mirrors, so they do non construct up a optical maser beam in the same manner. However, self-generated emanation that occurs within the fibre can be amplified if it is guided along the fibre, making background noise.

Figure 2.11 Amplified Spontaneous Emission Noise [ 5 ] .

Amplified self-generated emanation is spread across the whole runing scope of a fibre amplifier, as shown in Figure 2.9. The power is much lower than at the amplified wavelength, shown as extremums in Figure 2.9 [ 1 ] . However it remains in the background and can be amplified in consecutive amplifiers.

Figure 2.12 Simulation and Experimental feature of ASE versus wavelength ( EDFA ) [ 7 ]

Figure 2.8 shows the fake and experimental backward ASE profiles obtained at pump power of 109 mW. The fake backward ASE degrees are observed to be higher than the experimental backward ASE degrees. Such observation is besides noted for forward ASE profiles. As the pump power lessenings, the disagreement between the fake ASE profiles and the experimental ASE profiles alterations in a similar form. By and large, the fake ASE degree is about 13 dubnium higher than the experimental ASE degrees at high pump power.

The noise figure NF is a step of how much noise the amplifier adds to the signal.

The definition is:

Where, SNR is the signal-to-noise ratio.

Due to ASE, the SNRout at the amplifier end product is less than that at the input, SNRin. If the signal is much stronger than the noise, the noise figure can be written as equation below [ 2 ] :

Where ;

PASE is the ASE noise power,

H is Planck ‘s invariable,

I? is the frequence of the visible radiation,

G is Gain of EDFA

I”I?sp is the bandwidth of the noise ( i.e. the bandwidth of the EDFA ) .

2.6 Typical Specification of EDFA

There are many Erbium Doped Fiber Amplifier sell by different sellers. Each seller gave different specification to the EDFAs. Normally, seller would non sell merely one type of EDFA. The seller will sell different type such as Booster amplifier, in-line amplifier, pre-amplifier and addition flatten optical amplifier. Those types of optical amplifiers have different features in addition, noise figure and addition two-dimensionality.

There is a typical specification for a commercial EDFA which shown in Table 2.2 [ 2 ] .

Wavelength scope ( C-band )

1530 to 1565

nanometer

Wavelength scope ( L-band )

1570 to 1605

nanometer

Entire end product power

+23

dBm

Entire input power scope

-26 to +10

dBm

Addition

30

dubnium

Gain Flatness

0.8

dubnium

Noise figure Pin = 0dBm ( C-band )

5.5

dubnium

Noise figure Pin = 0dBm ( L-band )

6.5

dubnium

Polarization-dependent addition

0.4

dubnium

Polarization manner scattering

0.5

PS

Transient subsiding clip

50

Aµs

Transient overshoot/undershoot

0.5

dubnium

Power ingestion

20

Tungsten

Table 2.2 Typical Specifications of Commercially Available EDFAs [ 2 ] .

From Table 2.2, the addition, noise figure Pin = 0dBm ( C-band ) and addition two-dimensionality were the mention of the expected consequence in this undertaking.

2.7 OPTISYSTEM ( Software Used )

OptiSystem is a celebrated optical communicating system simulation bundle for the design, proving, and optimisation of virtually any type of optical nexus in the physical bed of a wide spectrum of optical webs, from long-haul systems to LANs and MANs. A system degree simulator based on the realistic mold of fiberoptic communicating systems, OptiSystem possesses a powerful new simulation environment and a genuinely hierarchal definition of constituents and systems. Its capablenesss can be easy expanded with the add-on of user constituents and seamless interfaces to a scope of widely used tools. There are many Models and Tools in Optisystem. The description of basic and relevant theoretical accounts or tools is show as below:

Erbium Doped Fiber

Description:

This theoretical account enables big and little input signal analysis, sing 980 nanometer or 1480 nanometer as wavelength pump. The numerical solution of the rate and extension equations, presuming a two-level Er system, enables to plan the amplifier in a co- or counter-propagating pump strategy. ASE is included in the simulations and fiber specifications such as geometrical parametric quantities ( for illustration, nucleus radius, Er doping radius, Er metastable life-time ) every bit good as and soaking up and emanation word picture ( cross-section, fiber loss ) are required as input files.

EDFA

Description:

The EDFA 1.0 designs Er-doped fibre amplifiers sing numerical solutions of the rate and the extension equations under stationary conditions. The theoretical account includes amplified self-generated emanation ( ASE ) as observed in the amplifier Erbium Doped Fiber 1.0, nevertheless this faculty enables to the user choosing frontward and/or rearward pump every bit good as the pump power values.

Trapezoidal Optical

Description:

This theoretical account is an optical filter with a trapezoidal frequence transportation map.

The transportation map is of the signifier:

Where:

H ( degree Fahrenheit ) is the filter transportation map, I± is the parameter Insertion loss.

HGauss ( degree Fahrenheit ) is the filter transportation map and

degree Fahrenheit is the frequence.

Optical Filter Analyzer

Description:

This theoretical account can pull out the frequence response of an optical constituent by comparing a mention optical signal before and after the computation.

Optical beginning

There are 6 types of optical beginning:

CW Laser

Pump Laser

White Light Beginning

Laser Measured

Laser Rate Equations

LED

Multiplexer and Demultiplexer

The WDM need the utilizing of multiplexer and demultiplexer. In the Optisys, multiplexer and demultiplexer is a ideal multiplexer and demultiplexer.

Chapter 3

RESEARCH METHODOLOGY

Chapter three explained the undertaking methodological analysis, approached taken and a closer expression how the undertaking was being conducted.

3.1 Understanding the undertaking

There are three aims of this undertaking which are to increases the end product signal power of the Erbium Doped fiber Amplifier ( EDFA ) , to flatten the addition of the Erbium Doped Fiber Amplifier and cut down the Amplified Spontaneous Emission ( ASE ) of Erbium Doped Fiber Amplifier.

Literature reappraisal on the three aims to happen out the methods to accomplish the three aims. The methods used in literature reappraisal are reexamining web site ‘s information, reexamining diary and mentions book. The method of reexamining web site ‘s information is for obtain the basic debut on the fibre ocular and Erbium Doped Fiber Amplifier. The 2nd methods of reexamining diary and mentions books are to happen out the methods of optimisation the amplifier, solutions of jobs and etc.

3.2 The Transmission Link

The Figure 3.1 is the transmittals link that traveling to utilize in the undertaking. The circuit is Erbium Doped Fiber Amplifier in multi-channels Wave Division Multiplexing ( WDM ) system. The WDM system used because the intent of this undertaking is to optimise the optical long draw transmittal nexus system and the WDM is the necessary system in the long draw transmittal nexus system.

There are 16 multiplexed signals which each channel spacing is 1nm. Most of the long draw transmittal system such as Fiber to the Home system is utilizing 16 or 32 channels in sender. At the receiving system side, there are 16 channels end product de-multiplexed by WDM de-multiplexer.

Figure 3.1 The loanblend EDFAs will be used in this undertaking

3.3 Output power of EDFA

The methods used to optimise the end product power are by taking the suited parametric quantities. The parametric quantities are the input power and length of fibre. The input power selected is -23dBm for each channel ( there are entire 16 channels ) . Last, taking C Band wavelength is one of the methods as C Band has larger addition belongings than L Band.

The addition of Erbium Doped Fiber amplifier is map of length of Erbium Doped Fiber. The Er doped fiber length is set between 1m and 20m. The length of Er doped fiber as the parametric quantity to optimise EDFA ‘s addition because the EDFA ‘s addition addition dramatically with the length of Er doped fibre.

The pump power was non chosen as the parametric quantity to optimise the addition because pump power used as parametric quantity for addition two-dimensionality of the EDFA.

3.4 Amplified Spontaneous Noise of EDFA

Since the Amplified Spontaneous Emission noise ( ASE noise ) is map of the addition, the noise figure was optimized by seting the addition of EDFA. This method will restrict the addition of the EDFA but it is more practical than the filtering method. The filtrating method requires an optical filter to filtrate the noise but it is hard and expensive to manufacture an optical filter [ 3 ] .

The amplified self-generated emanation noise of EDFA was been observed and measured by noise figure of the EDFA system. The equation below [ 2 ] shows that noise figure is map of ASE noise and addition.

Where ;

PASE is the ASE noise power,

H is Planck ‘s invariable,

I? is the frequence of the visible radiation,

G is Gain of EDFA

I”I?sp is the bandwidth of the noise ( i.e. the bandwidth of the EDFA ) .

3.5 Gain Flattening

In order to flattening the addition of Erbium Doped Fiber Amplifier, the intercrossed EDFAs is one of the methods. The Hybrid circuit was shown in Figure 3.1.

Hybrid EDFAs spilt two scopes of wavelength which are 1550nm to 1557nm and 1558nm to 1565nm. These two scopes of wavelength used because the addition is optimal at the both scopes of wavelength as shown in Figure 3.2.

The additions of the two wavelength scopes wavelength have different belongings of addition. Therefore, the addition of the two EDFAs adjusted to hold level addition at the same time. Last, both EDFAs were being adjusted to hold similar addition as each other and unite them. Double pump used in this undertaking because double pump have ability that control the addition of EDFA.

Figure 3.2 The built-in addition two-dimensionality for each wavelength graph

3.6 Measurement of the consequence

The consequences of this undertaking will be analyzed by utilizing double port WDM analyser. Double port WDM analyser is able to mensurate addition of EDFA, ratio of upper limit and minimal addition and noise figure of the EDFA. The BER analyser or oculus diagram was used to mensurate the BER rate of each wavelength at receiving system. The BER rate determines whether the EDFA designed is applicable in optical transmittal system.

Start

Literature

Reappraisal

Decrease of Amplified

Spontaneous Emission ( ASE )

Addition

Flattening

Optimization of

The

Output Power

Change

Methods

Simulation

Decrease of Amplified

Spontaneous Emission ( ASE )

Optimization of

The

Output Power

Addition

Flattening

NO

Consequence

Analysis

Yes

Decision

End

Figure 3.3 The Flow Chart

Chapter 4

RESULT AND DISCUSSION

Chapter four are concentrating on the certification of all the informations and concluding consequence of this undertaking. This chapter, the consequence from each simulation will be shown and there are treatments about the consequence.

4.1 Spacing of EDFA

The length of optical fibre was being varied to look into the spacing between the supporter amplifier and in-line amplifier. Assume that the input power is 0dBm and the addition of the supporter amplifier is 5dB. The input power of the transmittal system has been assumed as 0dBm because the maximal transmitter power of the long draw transmittal system is 13dBm. The length of optical fibre was being set into sweep manner loop from 110km to150km every bit shown as the Figure 4.1.

Figure 4.1 Sweep manner

The input power and the addition of the amplifier ( Booster amplifier ) have been set as below:

Input Power = 0dBm

Booster Amplifier = 5dB

Figure 4.2 The spacing length between supporter amplifier and the in-line amplifier.

Consequence of the simulation:

Table 4.1 Length of Optical Fiber versus end product signal with 5dB addition of Booster amplifier

The consequence of Table 4.1 determined that the maximal length of spacing between Booster amplifier and the first inline amplifier by cognizing the minimal input of the EDFA. The minimal input power EDFA is reciprocally relative to the end product power.

4.2 Gain Optimization

The intent of addition optimisation simulation is to look into and analyze the suited parametric quantities for the circuit. Harmonizing to literature reappraisal, the addition were affected by the input power, length of Erbium Doped fiber, pump power and wavelength.

4.2.1 Wavelength input signal

The addition of amplifier were varied with the signal wavelength. The sender beginning signal fixed to -23dBm because there are approximative 3dB to 2 dubnium at the WDM Multiplexer. Thus the input power is about -25dBm. The wavelength of sender from 1530nm to 1565nm which is called C-Band wavelength. The circuit of Figure 4.3 used double pump because this will increase the addition two-dimensionality of the EDFA. There are 32 channels where the wavelength of the sender starts from 1550nm to 1565nm. The spacing in between each channel is 1nm.

Figure 4.3 Simulation of the wavelength input signal from 1530nm to 1565nm

Consequence of the simulation:

Table 4.2 Wavelength versus addition ( nominal )

Figure 4.4 Wavelengths versus addition ( nominal ) Graph

The Gain two-dimensionality of the EDFA can be observed as seen in Figure 4.4. Since the method to flatten the addition of EDFA is Hybrid ( parallel ) two EDFAs that have different addition regard to wavelength. Therefore, the wavelengths used are 1550nm to 1557nm and 1558 to 1565nm. The addition for the two frequence scope being chosen because both of them have adequate two-dimensionality of addition and in high addition. The addition of the consequences inserted is the entire addition besides known as nominal addition where measured by WDM Dual port analyser as in Figure 4.5.

Figure 4.5 Dual Port WDM analyser and Nominal addition

The computation of nominal addition as below:

Where: GI»n = addition of the wavelength I»n

N = entire channel

From Table 4.2, there are 16 channels with different wavelength severally. The nominal addition can be calculated as below:

4.2.2 Input Power Signal

The input signal of the EDFA will impact the addition, addition two-dimensionality and Noise Figure. Since the method to obtain a level addition is intercrossed of two EDFA, therefore the simulaton were done in two different wavelength scope which are 1550nm to 1557nm and 1558 to 1565nm.

Figure 4.6 EDFA for frequence scope from 1550nm to 1557nm

Figure 4.7 EDFA for frequence scope from 1558nm to 1565nm

Consequences:

Table 4.3 Input power versus addition ( 1550nm to 1557nm )

Figure 4.8 Input power versus addition ( 1550nm to 1557nm ) Graph

Table 4.4 Input power versus addition ( 1558nm to 1565nm )

Figure 4.9 Input power versus addition ( 1558nm to 1565nm ) Graph

From the consequence, the increased in the entire addition is decreased with input power. Since the sender familial power is 0 dBm which was being set at old simulation, therefore the maximal input power is 0 dBm where the losingss being counted.

Since the typical input power is -26dBm to 10dBm. Therefore, the input power set to come close -25dBm because the smaller the input power of EDFA, the longer the length of spacing between EDFAs. Furthermore, the smaller the input power the higher the addition but the addition two-dimensionality will be addition.

The sender power of -23dBm is being simulated because the WDM Mux consist of about 2.7 dubnium losingss. Based from the simulation consequence of Table 4.1, the circuit was able to hold 130km to 140km spacing between the supporter amplifiers with the input power of -23dBm. Thus, the spacing of the Optical amplifier increased from 80km to 130km.

Figure 4.10 WDM Multiplxer losses=2.7dBm

4.2.3 Length of Erbium Doped Fiber

The addition of the EDFA is map of the length of the Erbium Doped Fiber. The simulation had been done by puting the length of Er doped fibre in the expanse manner. The length of fibre was varied from 0 metre to 20 metre.

Consequences:

Table 4.5 Length of Erbium Doped Fiber versus Addition

Figure 4.11 Length of Erbium Doped Fiber versus Gain Graph

The graph in Figure 4.11 shows that the length of the Er fibre in Erbium Doped Fiber Amplifier is incresed with the entire addition ( nominal addition ) . Furthermore, the addition increased in little value when the length of the Erbium Doped fiber increased from 10 metre to 20 metre. Since the Erbium Doped fibre is expensive, the length of Er doped fiber suited to utilize is 10 metre because of the cost and addition consideration.

4.2.4 Pump Power

The pump power will besides find the addition of the EDFA. The maximal pump that can subtained by the optical fibre is 1 W. Thus this simulation had been done by altering the pump to brush manner and varies it from 0 to 1 Watt.

Consequences:

Table 4.6 Pump Power versus Addition

Figure 4.12 Pump Power versus Gain Graph

Because the pump power increase the dramatically from 0 to 200mW. Therefore, the pump power suggested used in the scope of 0 to 200mW. The 2nd simulation being done to look into the pump power feature in EDFA of 200mW.

Consequences:

Table 4.7 Pump Power versus Addition

Figure 4.13 Pump Power versus Gain Graph

The maximal addition occurs at 200mWatt pump power. The 200mW pump power has been suggested to utilize in this undertaking.

4.3 Gain Flatness Optimization

The addition two-dimensionality can be optimized in many methods. The methods used in this undertaking is Hybrid of two EDFAs. The parallel intercrossed being used in this undertaking which is easier to optimise the addition two-dimensionality. Therefore, the simulation for two operating wavelength for EDFA being done which are 1550nm to 1557nm and 1558nm to 1565nm. The EDFA designed in double pump because double pump is easier to command the dynamic addition.

The Gain Flatness can be measured by ratio upper limit and minimal addition from the Dual Port WDM Analyzer. The larger the ratio, the lower the addition two-dimensionality. The ratio upper limit and minimal addition from wavelength of 1535nm to 1565nm is shown as Figure 4.14:

Figure 4.14 Ratio of upper limit and minimal addition Graph

The addition two-dimensionality can be calculated by equation below:

From the Figure 4.14, The addition two-dimensionality can be calculated as below:

= A± 4.5

4.3.1 Simulation for EDFA of frequence scope from 1550nm to 1557nm.

This simulation will merely run at wavelength of 1550nm to 1557nm. There 8 channels where each channel spacing is 1nm. This simulation is to look into the level addition at the operating wavelength. The length of the Erbium Doped Fiber set to brush manner where varied from 10 metre to 20 metre. This is to supply the different addition for the EDFA.

Figure 4.15 EDFA for frequence scope from 1550nm to 1557nm

Consequences:

Table 4.8 The addition two-dimensionality varies with addition ( 1550nm to 1557nm )

Figure 4.16 The addition two-dimensionality varies with addition graph

The Gain Flatness increased when the addition additions. But, the addition can non be set excessively high as it will increase the Noise of the EDFA. The addition suggested in this undertaking is 36.119dB and derive two-dimensionality is about A±0.71dB.

4.3.2 Simulation for EDFA of frequence scope from 1558nm to 1565nm.

This simulation will merely run at wavelength of 1558nm to 1565nm. There 8 channels where each channel spacing is 1nm. This simulation is same as old simulation where is to look into the level addition at the operating wavelength. The length of the Erbium Doped Fiber set to brush manner where varied from 10 metre to 20 metre.

Figure 4.17 EDFA for frequence scope from 1558nm to 1565nm

Consequences

Table 4.9 The addition two-dimensionality varies with addition ( 1558nm to 1565nm )

Figure 4.18 The addition two-dimensionality varies with addition graph

The Figure 4.16 shows that the addition additions with the length of the Er doped fiber until 17meter of the Er doped fibre. The suggested addition used in this EDFA circuit is 35.5012dB.

4.4 Final Simulation of The Hybrid EDFA

This simulation is the loanblend of two EDFAs. This simulation was to mensurate the addition, noise figure and addition two-dimensionality. Furthermore, the quality of end product power being investigated by utilizing the oculus diagram. The minimal BER measured had been made certain that below A-10-9.

Figure 4.19 Hybrid EDFA

Consequences:

Figure 4.20 Nominal addition, addition ratio max/min and Maximum NF

Table 4.10 Nominal addition, addition ratio max/min and Maximum NF

Wavelength/ nanometer

The Min BER From Eye Diagram

Eye Diagram

Min BER

1550

8.92873 x 10-139

1551

8.35385 x 10-207

1552

1.15412 x 10-163

1553

8.4381 x 10-139

1554

3.78135x 10-135

1555

3.27086x 10-150

1556

5.20888 x 10-115

1557

5.1161 x 10-147

1558

2.0591 x 10-150

1559

1.59684 x 10-120

1560

1.0206 x 10-202

1561

3.01029 x 10-153

1562

3.81049 x 10-140

1563

3.1592 x 10-125

1564

3.1592 x 10-125

1565

7.65416 x 10-153

Table 4.11 Eye Diagram and BER of each wavelength

The WDM Multiplexer ( 1 x 2 ) and WDM Demultiplexer ( 2 x 1 ) used to divide and unite the two wavelength scopes which are 1550nm to 1557nm and 1558nm to 1565nm. The minimal BER all achieved below A-10-9 and this proves that the EDFA is applicable. The oculus forms in the consequence show that the signals are non distorted excessively much.

The Noise Figure refers to the maximal value because the big Noise figure values provide high noise of the EDFA. The addition two-dimensionality of the EDFA is as below:

= A±0.6953dB

Chapter 5

CONCLUSION & A ; RECOMMENDATION

This Chapter will concentrate on the decision of the information contained in the study. This Chapter determine whether the aim is achieved.

5.1 Decision

In this study, the theory of the Erbium Doped Fiber Amplifier was described. Theory of parametric quantities that influence the EDFA has been explained in item. The nominal addition of the EDFA in this undertaking is 36.3523dB. The addition two-dimensionality of the EDFA designed is A±0.695285dB and the maximal noise figure of the EDFA is 4.00012dB.

The typical addition of the EDFA is 30dB. However, the typical noise figure and addition two-dimensionality of an EDFA are 5.5dB and A±0.8dB. The EDFA designed in this undertaking has been optimized from the typical specification as mentioned above. The addition was optimized 30 per centum from the typical addition of EDFA. Whereas, the noise figure of EDFA optimized to 37.50 per centum. The addition two-dimensionality was optimized in 15.06 per centum.

5.2 Recommendation

The Erbium Doped Fiber Amplifier designed in this undertaking can be optimized by farther research in future.

Optisystem ( Amplifier Edition ) was being recommended to utilize as the simulator to optimise the Erbium Doped Fiber Amplifier. The simulator Optisystem ( Amplifier Edition ) is more professional in optimisation of the Optical Amplifier.

The addition two-dimensionality of Erbium Doped Fiber Amplifier can be optimized by utilizing Automatic Gain Control. The automatic addition control system is a feedback system which able seting the addition of amplifier. Thus this will keep the addition two-dimensionality of the Erbium Doped Fiber Amplifier. This can be simulated by utilizing the Simulator of Optisystem ( Amplifier Edition ) . The Automatic Gain Control system is an electronic device therefore it can be done in hardware.

The Optical Amplifier, EDFA can be designed with its ain nucleus diameter or Numeric Aperture to acquire the optimal public presentation in practical. The nucleus diameter of Erbium Doped Fiber is map of Gain and Noise figure.

The designed EDFA was done by simulation ; this undertaking was recommended fabricated to hardware.

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Spectrum Of Erbium Doped Fiber Amplifier Computer Science Essay. (2020, Jun 02). Retrieved from http://studymoose.com/spectrum-of-erbium-doped-fiber-amplifier-computer-science-new-essay

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