94633

CONSTRUCTION OF FIBERS AND OPTICAL CABLES

Лабораторная работа

Коммуникация, связь, радиоэлектроника и цифровые приборы

Despite more than thirty-year experience, fiber technology is still at the beginning of the development – in commercial communication networks fiber has been used only since 1977. In spite of this comparatively small term, fiber optic had passed three important stages in the development and as a result there are three basic cable...

Английский

2015-09-15

2.17 MB

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Laboratory work № 1

construction OF FIBERs AND OPTICAL CABLES.

1 PURPOSE OF WORK

1.1 Learning structure of optical cables (OC) and theirs properties|feature| in dependence on purpose|purpose| of cable.

1.2 Learning constructional features of optical fibers and other elements of OC.

2 MAIN POSITIONS

2.1 Types|typestyle| of fiber structures |

International Electrotechnical Commission  in the offer [1] has divided all OC into the following basic|main| types|typestyle|:

2.1.1 Cables for a direct laying into the earth.

2.1.2 Cables for laying into collectors and pipes.

2.1.3 Cables for air hanging.

2.1.4 Submarine cables (for relatively short water obstacles).

2.1.5 Cables for internal laying.

2.1.6 Cables for interobjective connection.

2.1.7 Mounting cables.

2.1.8 Cables for special purposes (different from the general-purpose cables in special requirements, caused by the features of their exploitation or by climatic area).

2.1.9 Deep-sea cables (cables are pressurized|encapsulate|, hydroacoustic, load carrying|).

In addition OC are distinguished:

2.2.1 Upon the material of fiber: fiber made of quartz, multicomponent glass, quartz jointed with polymer or polymer fibers.

2.2.2 Upon the fiber structure:| single-fiber cables and cables with optical harnesses|garrot|.

2.2.3 Upon the type of refractive index – as a rule, there’re graded-index, step-index fibers.

2.2.4 Upon|quantity| the number|quantity| of |passes||typestyle| waves (modes) transmitted through a fiber:|  multimode,| single-mode OC|.

2.2.5 Upon the material used to produce OF there are cables with normal and enhanced thermal resistance.

2.2.6 Upon presence (absence) of conducting| threads: simple and combined cables.

2.2.7 Upon presence of shield: shielded and unshielded OC.

2.2.8 Upon structure and materials of protective coverings there are filaments, films, bands.

2.2.9 Upon the technique of producing there are methods of extruding, pin thermal welding, enamelling, etc.

2.2.10 Upon the kind of laying and assembling there’re cables for the stationary and mobile objects.

Despite|in spite of| more than|more than| thirty-year| experience|tentative|, fiber| technology|technicology| is still|been| at the beginning of|in the beginning of| the development – in commercial communication networks fiber has been used only since 1977. In spite of|in spite of| this comparatively small term, fiber optic had passed|reeve| three important stages in the development and as a result|as a result| there are three basic|main| cable structures called concentric cables, cables with shaped core| and with shaped belt core|.

Concentric cables. These cables appeared as a result of first cable developments. The fibers are contained in or dense coverage of polyamide either freely fixed tubes of the optical module (OM), whereas the tubes convolve round a central load-bearing element and form cable with concentric structure. Such cables contain up to 144 fibers and from 2 to 12 fibers in every tube (Fig. 2.1, a).

Cables with shaped core. Development of cables with shaped core had led to more powerful and strong ones containing up to 48 fibers, and from 2 to 8 fibers  in each core slot or in each freely celled OM tube inserted to the slot. Further development of the load-bearing element had led to spiral-shaped core structure. Core slots go|leave| spiral over its entire length|lenght| or in form of "SZ"-twisting| changing slot’s direction to the right and to the left side per a few meters and the transition points per a few turns.|counter-clockwise| |flank| |from| |a little| |meter-ampere| |transition| |from| |a little| |Felge|

Advantages of such a structure appear|signifying| in increasing|rise| of durability|resistibility| against influence of the compressive forces|strenth||vising| due to |non-load-bearing|the shaped core and the OM tubes which|pipe| protect fibers (Fig.| 2.1, b).

Cables with shaped belt core. Increasing demands for more compact packing fibers in the cables and acceleration of fiber welding had led to the third type of structure of optical cables – with shaped belt core. For example, they contain up to 192 fibers. Each slot in a cable with shaped belt core can place up to 4 belt layers, where each tape of a layer contains four or eight fibers. Cables with shaped belt core are used for interurban and local communication networks (Fig. 2.1, c).

Any cable design should provide fiber protection against any external factors, such as crushing, tensile, friction, corrosion and ageing strength - without reducing fiber capacity.

Fiber is sensible material to stretching and bending. A primary purpose  of cable designing is to create protection for fibers, wich should operate during the production, mounting and exploitation of cable. If fiber is subjected some strong external influences, the critical parameters of fiber, such as operational lifetime and attenuation might be damaged. This problem can be solved in two ways. First, while assembling cable, all the fibers must conform to necessary quality – in production it is provided by the system of guarantee used at the plant. Secondly, technology and designing of cables should be conducted by economic way in order to meet the requirements offered taking into account the way of assembling and puprpose of the produce.

Selecting cable design for certain purpose it is nessesary to take into account the following aspects :

– cable compliance|homology| with State Standard and Specification  which are worked out in accordance with|according to| requirements|claiming|, for example|eg| ITU-T| (International Telecommunications Union - Telecommunications sector), IEC| (International Electrotechnical Commission), CENELEC| (Commission Europйenne de Normalisation Йlectrique - the EU standards organization for electrical goods);

OC compliance|homology| with necessary operating characteristics. When determining  fiber bandwidth, it is necessary to take into consideration fiber loss and requirements to its fluctuation. These characteristics should meet the hardest conditions uccured in places of exploitation;

– cables should be easy-to-use. It should have flexibility, colour code, light weight, crushing, flexural and tensile strength, create conditions for rapid mounting and reliable exploitation;

– cables should be convenient in welding|weldment| and inputting into terminal devices|endter. Cable and fiber easy identification facilitates|easy| welding|weldment| and makes it more accurate. External|outward| cable protective covers should be easily taken|rise| off. Also imoptant things are|appear|| fibers chipping, fiber and cable joining,|halving| welding spot protecting|seat|;

– cables should have convenient marking. Marking assists rapid mounting, repair and reduces cable line idle time;

cable should meet proposed requirements taking into account climatic conditions in the place of exploitation. Selecting the appropriate cable for given purpose, it is necessary to take account of the environmental conditions, in which cable is going to be exploited.

Cables for laying in canalization or for direct laying into the earth|earth| should be armored|armour-plate| to protect|protection| them against abrasion in the rocky|rocky| soil|earth| and damage caused|cause|  by rodents. Corrugated armoring tapes are recommended to use for such cables.|

For submarine cables, cables for direct laying into the soil with rather adverse conditions and for laying in places, where especial mechanical strength is required|claiming| |stage| |by| |mechit is necessary to prefer|steel-wire| armoring wire|.

When developing overground cables to select the load-bearing element should be taken into account the height of the OC brackets, climatic features and the distance between poles. Sometimes selection of the stronger load-bearing element and increase in the distance between neighboring poles brings significiant benefits. An important factor is cable resistance to vibrations created by wind as well as its ability to withstand sticking of ice and freeze in cold climatic conditions.

Optical cables insignificantly effect the environment. Even then to reduce its influence factories should not use harmful to the environment materials.

2.2 Basic OC|main| elements

|

As you know, in every way of practical use fiber should be packed into cable protected by the external protective coverings. For any cable the important characteristics are breaking strength boundary, compression and bending stress resistance, flexibility, external influences protection, operating temperature range, life time, etc.

These characteristic values depends on a certain purpose of cable. For example, OC for external use are in extreme conditions. They should resist temperature fluctuations, sticking of ice, freeze, strong wind in case they are hanged on the poles, mechanical damage and rodents, which can damage them in case they lay underground. Obviously, they should be firmer than patch cords, which connect some equipment inside the building and operates within the controlled conditions. A cable laid under the carpet in the office, where people walk on, move arm-chairs, should bear the additional load comparatively with  cable inside the walls of that office.

Figure 2.2 presents the main components of a certain objective single-fiber OC. There are various cable designs|varied|, but all of them have the same |common|her|appe|downstream|components|reductant|: fiber; buffer dense|tight| protective covering (DPC); load-bearing element; external|outward| cover.

Composition of basic|main| OC elements is determined by the features|feature| of optical fiber: its high sensitivity to|by| mechanical|mechanics| influence (bending, longitudinal and transversal loading), to|by| effects of different|diverse| physical|&climatic environmental factors (temperature fluctuation, damp|moisture|, sun radiation). Therefore the majority OC designs includes besides fiber:

 load-bearing elements, which increase cable high breaking strength and bending radius;

reinforcing| elements, which increase its transverse loading strength;

separating layers, which reduce pressure of different elements on each other;

fillers (solid plastic cores);

external|outward| covers, including armored ones,| which|what| preserve from penetration of moisture as well as external|outward| mechanical|mechanics| influence.

The OC designs could also contain insulated metallic wires for remote power supply and automatic remote control and management organization.

There are two options for OC [2] differ in the fiber and |truss|load-bearing elements placment. One option is to place load-bearing element in the|heartland| core of cable, whereas|but| fibers lies concentricly round|concerning| the element element. The second|second-| option is to place load-bearing elements outside fibers which|what| are in the centre|center||portion| of cable. There are both variants shown |in Figure 2.3.

After the types of fiber packing|detention| in OC, there are floating, or bunchy,| packing|detention| (Fig.| 2.3|bu) and band packing,|detention| which is demonstrated|pointed| in Figure| 2.4, where 1 - optical fiber, 2 - filler, for example|eg|, made of foam plastic, 3 - polyethylene jacket, 4 - belt|incle| with fibers.

There’re two basic|main| methods|heliochrome| of twisting used|: modular and stratified. In the first|first-run| case fiber is twisted together|alongwith| in little|small| looms forming large|great| groups, which form harnesses|complex|garrot||pilchar. In the second|second-| case for|formation| cable core formaion fiber is clustered to plane or concentric layers. In both variants|heliochrome| there is some packing  between fiber layers or bundles|fabric| to slack tension, which| appears when some load, especially transverse one, has an effect on cable|in particular case|.

Cross-section of some OCs|certain| for external|outward| laying, which contain|maintain| elements mentioned above, is demonstrated|pointed| in Figure| 2.5|earlie|enumerate|, where 1 - external|outward| cover, 2 - reinforcing| elements, 3 - internal|inlying| cover, 4 - fastening band|incle|, 5 - soft pillow, 6 – fiber covered with the polymer, 7  load-bearing element, 8 - fillers, 9 - steel| corrugated cable armor.

Types of material which the elements of cables are made of depend on cable purpose (interurban, city, object, submarine or mounting cable).

Special|use| materials are used for load-bearing elements. They are possessed of the high modulus of elasticity, high tensile strength, which exceeds the maximal strength of any cable material|fabric|, high flexibility and relatively small mass per length unit|springback||lengthening-out||what||Max||fabric||mini||lenght|. Load-bearing elements can be formed|does| as insulating cord made| of a solid polymer, for example|eg| polyamine|,|garrot| or harness from thin|fine-bored| kevlar threads|, it’s also can be made of glass-reinforced resin or metal like copper|cooper| or steel|steel-wire| wire, hawser.|

Separating layers are made of soft|mild| materials|fabric|, for example|eg| of polyurethane| or other soft|mild| cellular plastics. Fastening belts interlay between fiber layers|incle|, also implementing damper functions.

Reinforcing elements can be formed as thick plastic covers, which include metallic wires or high-modulus polymeric fibers, metallic or corrugated covers of aluminium, copper or steel.

Polyethylene, polyvinylchloride, polyurethane, thermoplastic rubber, aluminium are used for protective covers.

2.3 OPTICAL FIBER

Optical fiber belongs to the class of dielectric waveguides, which work is based on principle of total internal reflection.

The following OF groups are distinguished|downstream|: multimode (M), single-mode without|senza| preserving polarization of radiation and single-mode| with preserving|safety| polarization of radiation. The group of multimode fiber is divided into two sub-groups: step-index optical fiber and graded-index optical fiber|refringence|. In dependence on materials of|fabric| fiber cladding and core it is classified into the followings|downstream| groups|appearance|: 1 –  fiber cladding and core made of quartz|silex|; 2 - core of quartz|silex|, cladding of|but| polymer; 3 - core and cladding made of multicomponent|reductant| glass; 4 - core and cladding made of polymer|fabric|; 5 – other variants.

International fiber classification system is based on ITU-T recommendations  G.650 and IEC publications 60793 [3, 4]. Thus according to IEC recommendations there’re two OF classes: A and B, which multimode and single-mode fiber respectively belongs to. The category of multimode OF is defined by the material of fiber core and cladding and type of refractive index as well, whereas the category of single-mode fibers is defined by bearing wavelength (or bearing wavelengths) and zero dispersion wavelength  (table 2.1).

Table 2.1 – OF standards

Multimode fibers standards

Standart

Material

Type

Power range, и

А1

glass core,

glass cladding

graded-index fiber

А2.1

glass core,

glass cladding

Quasistep-index optical fiber

А2.2

glass core,

glass cladding

step-index optical fiber

А3

 glass core,

glass cladding

step-index optical fiber

А4

polymeric fiber

Gradient-index optical fiber

-

Single-mode fiber standards

Standarts

Material

Nominal zero dispersion wavelength, nm

Bearing wavelength

, nm

В1.1

glass core,

 glass cladding

1300

1310

В1.2

glass core,

 glass cladding

1300

1550

В2

glass core,

 glass cladding

1550

1550

В3

glass core,

 glass cladding

1300 and 1550

1310 and 1550

As in |note|above, the first type of fiber which|first-run| was used|use| in communication networks was multimode one. A number of modes can pass|widen| multimode OF simultaneously, each of them injected with different angle into the lightguide|divers. Multimode fiber has a relatively large|great| diameter of core (standard values|importance| 50 and 62,5 microns|) and consequently|concordantly| large|great| numerical aperture which facilitates|easy| fiber|its| mounting and exploitation|maintainance||in relation to|. The cardinal|main| fault|failing| of such fiber is|appear| an intermodal dispersion presence||disperision|. To reduce this effect the |phenomenmultimode gradient-index optical fiber was designed|profil|metric||refringence|, however the|wholly| complete removal| of intermodal dispersion|disperision| in multimode fiber is unsuccessful, which is explained|unravele| both index profile imperfection|refringence| and presence of the so-called|so called| twisted modes, which arise up as a consequence of OF axial symmetry, so that|what| its impossible to get rid of them in principle.

Gradient-index OF is characterized|describe| by the type|profile| of index|metric| profile|refringence| (IP) which is|appear| the monotonically decreasing function of radius within fiber|its| core. Optimal IP |quality-controlled|type is|profile||metric||refringence| parabolic one|parablic| (Fig.| 2.6).

However to get the parabolic|parablic| IP type in the real life is virtually|receive|profile||metri|refringence| impossible because of|because of| imperfection of technology of|technicology| producing blanks, therefore|that is why| they usually use term quasiparabolic| IP type|profile||metric||refringence|, which is characterized by multi-stageness|multi-stage| and the central dip of IP characteristic|center| which|what| worsen dispersive OF properties|virtue| (Fig.| 2.6).

The simplest is unclad OF which consists only of one type of dielectric|solator||typestyle|. On its|its| surface|supface| index|metric| of refraction|refringence||variate| jumps|saltus| from value n1|importance| (index of refraction inside fiber) to|by| value|importance| n2 (refractive index in contiguous the fiber environment|Wednesday|). However passing|passes| wave’s fields in such OF partially gets to surrounding space and any|some| supporting|underprop| fiber structure which leads to fiber|to| transfer characteristics distortion. Besides the field penetration into nearby|neighbouring| OF takes place. Therefore such fibers did not find any practical application, whereas single-layer-coatedfiber which consists of core and cladding with different optical properties are used|use|.|diverse||virtue| It provides|secure| better conditions of reflection at the boundary| of|division| core and cladding and decrease the field penetration outside the core|afte|border|. Wave propagation occurs in the core, and|but| the field which penetrates into the the cladding attenuates| exponentially. Therefore, by selecting an appropriate cladding depth, field on an external|outward| surface|supface| of fiber can be almost insignificant|mini|. In case not following this condition|do||COND|, field of the passing|passes| wave will exist outside the cladding that leads to|by| increase of |height|signal attenuation in the cable. 

If to take into account loss of signal only the sufficient|suffite||appear| cladding depth is 20...30 microns| [2]. However because of the fiber core size of|dimension| 5...50 microns|, fiber with such cladding would have relatively small diameter and low|subzero| mechanical strength|in relation to|. Therefore fiber cladding is thicker|heavy-gauge|, its external|outward| diameter is 125...150 microns|.

Further fiber reinforcement is implemented by protective covers (see|q.v.| Fig.. 2.2) which contain|maintain| the laked film with thickness of 5...10 microns| to prevent occurrence|occurring| and expansion of microcracks|.

Purpose of next layers is to eliminate transverse forces influence on OF and increase fiber breaking strength [5]. It could be a buffer layer made of elastic polymer, which protects fiber glass part from pressing, and external layer of polymeric material with the high modulus of elasticity which works in compression and tension [5]. The external diameter of fully covered OF is about 0,7...1,0 mm.

Also there are fibers without|senza| dense|tight| packing|detention| into protective covers|safe-covering|. There are two cases possible. First one is to lay the|lay| primary cover (single-layer-coatedfiber|) over the cladding. Second one is to lay primary and secondary|secondary| covers|safe-covering| (double-clad fiber|). The external|outward| diameter of such OF is|folds| 250 microns|.

As in above, besides the step-index fibers gradient-index fibers are used, index of refraction of the latter changes gradually as function of core raius.

There are shown|but| cross-sections and index profiles|metric||refringence| of|concordantly| step-index and single-layer| gradient-index OF in Figure 2.7, where n1, n2, n0 are indexes of refraction of respectively  fiber core, its cladding and surrounding environment.

Step-index fiber has so n1 and n2 that following expression takes place

Usually , and . 

The gradient fiber has radial index profile, which changes according to parabolic law (with maximum in the center and minimum at the periphery). Its index of refraction is determined at any point distant in r from the center by the expression [6]:

                                                                                   (1)

Where a – fiber core radius, u - index of power, and      |ratio|

An advantage of such  fibers is simpler  coordination with the emission source. It is conditioned with their potential to be made thicker than step fiber, because the latter contains more modes than gradient one with the same size. Another adventage of gradient fibers is lower dispersion.

 

In tables A..1 and A.2 general properties are shown of single-mode and multimode OF produced|discharge| by some|certain| leading companies in accordance with|according to| the International Standard requirements|claiming|[4] and ITU-T recommendations| G.651|pointed|,| G.652,| G.653,| G.654,| G.653 [3, 7, 8, 9, 10, 11].

3 KEY QUESTIONS

3.1 Tell the requirements to the OC designs? 

3.2 What do OC elements consist of?

3.3 What properties need to have materials used for making OF?

3.4 What materials are used for OF production?

3.5 Constructive protective measures against cross-effect between nearby OF inside OC.

3.6 Types of OF according to theirs structure, their features.

3.7 Single-mode and multimode OF, their sizes.

3.8 Types of OF packing in cable.

3.9 What requirements|virtue| must meet|possess| load-bearing and reinforcing elements| of OC designs. What materials|fabric| are they made from?

3.10 Modifications of load-bearing and reinforcing elements placed| in OC, their advantages and disadvantages|failing|.

3.11 What is the purpose of OC external cover?

3.12 OC classification on purpose.

3.13 What is numerical aperture of OF?

4 HOME TASK

4.1 Using recommended literature learn classification and types of OC designs, their features.

4.2 Prepare the recitation for key questions.

4.3 Prepare the laboratory work report, which should contain title of the laboratory work, its purpose, picture of the OC cross-section performed according to an option of home task from the table 4.1 (the task option is determined by the  sequence number of student in the register).

5 LABORATORY TASK

5.1 Familiarize with equipment in the workplace and coordimare with lecturer plan of the laboratory work fulfilment.

5.2 Learn|study| the design of the OC pattern|model| given you by lecturer and draw it|paint| cross-section|drawing||traversal||.

5.3 Using|use| the МБС-9 microscope|microscop|, determine the type| of given|publishes||model| fibers (either it is step-index fiber or gradient-index one) and draw the index profile types|paint||profilitsits ||refringence|. Determine sizes|dimension| of OF elements. To gain it rotate the knob of the microscope focusing  mechanism until the sharp|hairpin| view of fiber end,|representation| then |Felge|count up the number of scale labels|scaleplate| on the measuring area. |what|The gained number multiply by a number given|specified| in the converting table (table 4.2), which|what| conforms the microscope|microscop| zoom|what| of measurement running|implemen|that is why|.

To determine|definition| the OF type it is necessary to light the opposite to examining fiber end||microscop|. The microscope lighting bulb turns on with toggle on transformer block. Switch on only|switch| after instructor’s permission.

5.4 Using a caliper determine the OC element sizes.

Table 4.2 – Converting table

Toggle scale zoom

One scale mark,

1 mm

Size across flats of square,

1 mm

corresponds the size of the object

0,6

1

2

4

7

0,17

0,1

0,05

0,025

0,014

1,7

1,0

0,5

0,25

0,14

6 EQUIPMENT

6.1 Examining OC patterns.

6.2 МБС-9 microscope.

6.3 Trammel.

7 CONTENT OF A REPORT

7.1 Title and purpose of work.

7.2 Raw data of home task given and corresponding it pictures of the OC cross-section.

7.3 Picture of OC cross-section, set by instructor.

7.4 OF type determination|definition| results, picture of their index profiles||profile||metric||refringence|, and also sizes|dimension| of  OF constructional elements.

8 LITERATURE

8.1 ITU-T Telecommunications sector. Constructions, laying, joining, protection optical cables. Geneva, 1994, ISB 92-61-04904-4.

8.2 Волоконно-оптические кабели. Д.В. Иоргачев, О.В. Бондаренко, А.Ф. Дащенко, А.В. Усов. - Одесса.: Астропринт. - 2000.

8.3 ITU-T. Recommendation G.650 – 1997, Definition of and test methods for the relevant parameters of single-mode fibers.

8.4 IEC 60793-2. International standard. Optical fibers. Product specifications.

8.5 Семенов Н.А. Оптические кабели связи. - М.: Радио и связь, 1981.

8.6 Гроднев И.И., Ларин Ю.Т., Теумин И.И. Оптические кабели. -М.:Энергоатомиздат, 1985.

8.7 ITU-T. Recommendation G.652. Characteristics of a single-mode optical fiber cable.

8.8 ITU-T. Recommendation G.653. Characteristics of a dispersion-shifted single-mode optical fiber cable.

8.9 ITU-T. Recommendation G.654. Characteristics of a cut-off shifted single-mode optical fiber cable.

8.10 ITU-T. Recommendation G.655. Characteristics of a non-zero dispersion-shifted single-mode optical fiber cable.

8.11 ITU-T. Recommendation G.651. Characteristics of a 50/125 multimode graded index optical fiber cable.

9 APPENDIX

Table 9.1 – Multimode OF characteristics produced by some companies

Company

Lucent Technologies

Corning

Sizes

Core diameter, micons

62,5±3,0

62,5±3,0

50±3,0

Core disconcentricity, %

6,0

5,0

5,0

Cladding diameter, microns

125,0±1,0

125,0±0,2

125,0±0,2

Cover diameter, microns

245,0±10

245,0±10

245,0±10

Dispersion

Zero dispersion wavelength, nm

13281350

13321354

12971316

Attenuation, dB/km

Maximum at: λ=850 nm

λ=1300 nm

2,83,5

0,71,0

2,83,0

0,60,7

2,50,8

2,42,5

0,50,8

Bending attenuation (100 turns)

λ=1300 nm

-

<0,5

<0,5

Bandwidth Hz*km)

at: λ=850 nm

λ=1300 nm

160250

4001000

160200

200600

400600

4001000

Additional characteristics

Refractive index difference, %

2,0

2,0

1,0

Refractive indexes efficiency at: λ=850 nm

           λ=1300 nm

1,496

1,491

1,496

1,487

1,490

1,486

Numerical aperture

0,275±0,015

0,275±0,015

0,200±0,015

Index profile

Gradient

gradient

gradient

Ending of table 9. 1  

Company

Fujikura

Sumitomo Electric

Sizes

Core diameter, micons

50±3,0

50±3,0

62,5±3,0

100±5

Core disconcentricity, %

-

-

-

-

Cladding diameter, microns

125,0

125,0±2,0

125,0±2,0

140,0±3,0

Cover diameter, microns

250,0

250,0±10

250,0±10

250,0±10

Dispersion

Zero dispersion wavelength, nm

-

-

-

-

Attenuation, dB/km

Maximum at: λ=850 nm

λ=1300 nm

3,0

1,0

3,0

1,0

2,5

0,7

3,5

1,5

3,5

1,5

4,0

2,0

4,0

2,0

Bandwidth Hz*km)

at: λ=850 nm

λ=1300 nm

200500

200500

200

500

400

600

150

500

150

200

150

500

100

300

Additional characteristics

Refractive index difference, %

-

-

-

-

Refractive index efficiency at:

                         λ=  850 nm

                         λ=1300 nm

-

-

-

-

-

-

-

-

Numerical aperture

-

0,210±0,02

0,275±0,015

0,280±0,02

Index profile

Gradient

Gradient

Gradient

Gradient

Table 9. 2 – Characteristics of single-mode OF produced by some companies

Company

Luсent Technogies

Trade sign

SM-9/125

AllWave

TrueWave

TrueWave RS

Fiber type

SSF

NZDSF

NZDSF

NZDSF

ITU-T equivalence

G.652

G.655

G.655

G.655

Sizes

Mode spot diameter, microns, at wavelength in

- 1310 nm

9,3±0,5

9,3±0,5

-

-

- 1550 nm

10,5±1,0

10,5±1,0

8,4±0,6

8,4±0,6

Cutoff wavelenth, nm

- in fiber

1150±1350

-

-

-

- in cable

1260

1260

1260

1260

Cladding diameter, microns

125,01,0

125,01,0

125,01,0

125,01,0

Cover diameter, microns

245,010

245,010

245,01,0

245,01,0

Dispersion

Zero dispersion wavelength, nm 

13001322 1312 (nm)

13001322

15401560

1450

chromatic dispersion coefficient, picosecond/nm*km

18

(1550 nm)

-

0,84,6

1550 nm

-9 1310 nm

4,52 (1550nm)

polarization mode dispersion, picosecond/

0,2

0,5

0,5

(1550 nm)

0,5

(1550 nm)

Attenuation dB/km

Maximum at wavelength in

- 1310 nm

0,350,40

0,350,40

-

-

- 1550 nm

0,210,30

0,210,25

0,20,25

0,220,25

Maximum at a range 12851330 nm exceeds attenuation at 1310 nm

Less than 0,1

Less than 0,1

-

-

Maximum at a range 15251575 nm exceeds attenuation at 1550 nm

Less than 0,05

Less than 0,05

Less than 0,3

Less than 0,27-0,3

Attenuation at ОН peak (13833 nm)

2,0

0,31

1,0

2,0

Additional characteristics

Stripping force, N

1,3 ... 8,9

1,3 ... 8,9

1,3 ... 8,9

1,3 ... 8,9

Effective group index

- 1310 nm

1,466

1,466

1,4738

1,471

- 1550 nm

1,467

1,467

1,4732

1,470

Numerical aperuture

0,12

-

-

-

Refractive index difference,%

0,33

-

0,75

-

Index profile

step

-

triangle

-

operating optical windows, nm

1310/1550

1285-1620

1530-1560

1525-1620

Company

Corning

Trade sign

LEAF

SMF-LS

ОВ с SMF-28

ОВ Titan

Fiber type

NZDSF

NZDSF

SSF

SSF

ITU-T equivalence 

G.655

G.655

G.652

G.652

Sizes

Mode spot diameter,microns, at wavelenth in

- 1310 nm

-

6,6

9,30,5

9,30,5

- 1550 nm

910

8,40,5

10,51,0

10,51,0

Cutoff wavelenth,                                     nm

- in fiber

- in cable

1260

1260

1260

1260

Cladding diameter, microns

125,01,0

125,01,0

125,01,0

125,01,0

Cover diameter, microns

245,01,0

245,01,0

245,01,0

245,01,0

Dispersion

Zero dispersion wavelength, nm

-

15301560

1301,51321,5 1312 (nom)

1301,51321,5 1312 (nom)

chromatic dispersion coefficient, picosecond/nm*km

-

-

1,06,0 15301565 nm

-0,1-3,5 (1550 nm)

polarization mode dispersion, picosecond/

0,2

(1550 nm)

0,5

(1550 nm)

0,5

0,5

Attenuation dB/km

Maximum at wavelength in

-1310 nm

0,5

0,5

0,34

0,40

-1550 nm

0,25

0,25

0,2

0,30

Maximum at a range 12851330 nm exceeds attenuation at 1310 nm

-

-

Less than 0,05

Less than 0,05

Maximum at a range 15251575 nm exceeds attenuation at 11550 nm

Less than 0,05

Less than 0,05

Less than  0,05

Less than  0,05

Attenuation at ОН peak (13833 nm)

1,0

2,0

2,1

2,1

Additional characteristics

Effective group index

- 1310 nm

-

1,471

1,4675

1,4675

- 1550 nm

1,469

1,470

1,4681

1,4681

Index profile

-

0,16

0,13

0,13

-

-

0,36

0,36

trident

trident

step

Step

Operating optical windows, nm

1530-1625

1530-1560

1310/1550

1310/1550

Company

Fujikura

Trade sign

SM-10/125

DSM-8/125

DSMNZ-9/125

Fiber type

SSF

DSF

NZDSF

ITU-T equivalence 

G.652

G.653

G.655

Sizes

Mode spot diameter,microns, at wavelenth in

- 1310 nm

8,5-9,6

-

-

- 1550 nm

8,1

9,50,5

Cutoff wavelenth, nm

- in fiber

11801320

-

1450

- in cable

-

-

-

Cladding diameter, microns

125,01,5

125,01,0

125,01,0

Cover diameter, microns

245,010

245,010

245,010

Dispersion

Zero dispersion wavelength, nm

1301-1322

1525-1575

-

chromatic dispersion coefficient, picosecond/nm*km

3,5 (1285-1330нм) 18(1550нм)

3,5 (1525-1575нм)

1,0-6,0 (1550нм)

Polarization mode dispersion, picosecond/

-

0,5

0,5

Attenuation dB/km

Maximum at wavelength in

- 1310 nm

0,34

0,45

- 1550 nm

0,22

0,3

0,25

Maximum at a range 12851330 nm exceeds attenuation at 1310 nm

Less than

0,05

Less than

0,05

-

Maximum at a range 15251575 nm exceeds attenuation at 11550 nm

Less than

0,05

Less than

0,05

0,25

Attenuation at ОН peak (13833 nm)

1,0

1,0

-

Additional characteristics

Effective group index at

- 1310 nm

1,465

1,468

-

- 1550 nm

1,465

1,468

1,469

Numerical aperture

-

-

-

Refractive indexes difference,%

0,36

-

-

Index profile

Step

-

-

Operating optical windows, nm

1300/1550

1310/1550

1310/1550

Figure 2.7 – Constructions of  single-layer-coated and double-clad fibers :

а) with step-index profile; b) with graded-index profile

b)

Z

0

n1

n

Z

a)

Figure 2.2 – OC basic elements

c)

1

2

3

4

5

6

7

8

Figure 2.5 – Typical constructions of OC for external laying

1

3

4

7

6

8

9

а)

b)

Figure 2.1 – Types OC constructions:

а – concentric;

bwith shaped core;

cwith shaped belt core

Protective cover

OF

Load-bearing element

Figure 2.3 – OC constructions with different fiber and load-bearing element placing

Figure 2.4 – OC designs with band fiber packing

4

3

2

1

n0

n2

n1

n


 

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