Fiber Optics

Fiber CouplersFibers Fiber Collimators

Fiber Coupler SystemsFiber Adapters for LINOS Systems

Product Lines

Imaging Systems

Cameras

Laser Components

A Brief Profile of LINOS

• Systems provider and globally leading supplier of sophisticated optical product solutions

• Core expertise in the development of complex optical components and systems

• System integration on the basis of holistic technology know-how

• Proficiency in production processes of glass machining all the way to complex assembly

2

Contents

Fiber Coupler Laser Systems

Application Areas 4

Fiber Couplers

Introduction 6Choice of Lenses and Order Numbers 7

Fibers

Functional Principle 8Fiber Configuration 10Ordering Information 12

Fiber Collimators

Functional Principle 14Ordering Information 15

Fiber Coupler Systems

Functional Principle 16Ordering Information 17

Accessories

Adapters for LINOS Systems 18

3

Fiber Coupler Laser Systems

Application Areas

The use of the laser in medicine has opened up new avenues in therapy and diagnosis. The development of fiber coupler laser systems enables special medical requirements to be easily met. An elegant and flexible method is the use of a fiber light guide for trans-porting light from the laser to the application. The new fiber collimation system from LINOS has been specially developed for use in sophisticated laser applications.

Parameters such as

• Laser power and power density • Duration of exposure to a laser beam• Wavelength (determines the depth of penetration into tissue) • Beam quality

require the use of a variety of laser systems in nearly every medical field.Fiber coupler laser systems allow physical separation of an equipment setup from a laser source.

In addition, these systems enable a laser beam to be accurately directed at the area to be treated. Moreover, several wavelengths can be coupled into a single-mode fiber. The task to focus the laser beams to allow efficient treatment of a specific area without damaging the surrounding tissue. The particular type of laser determines the lesion geometry in terms of width and depth, and this geometry can be re-stricted to various types of lesion:

• Ablation • Coagulation• Disruption• Vaporization, etc.

Example:

If one of the most important commercial types of laser is used, i.e. an argon laser (Ar+, 488 nm or 514 nm), the medical benefits are obvious:

• Low penetration depth• Moderately selective absorption in hemoglobin and melanin• Performance in the range of 60 mW (ultraviolet) to 100 mW (bluish green)• High performance density

The major areas of application for argon lasers (488 nm or 514 nm) and krypton lasers (647 nm or 568 nm) at an operating wavelength ranging of 450-640 nm are in ophthalmology, derma-tology and in otolaryngology (ENT medicine). The krypton laser has a simi-lar construction and operates within the red spectral range.

In ophthalmology fiber coupler laser systems are used to treat:

• Diabetic retinopathy• Aftercataracts• Glaucoma (Ar+)• Changes in lid tissue• Photocoagulation to prevent retina detachment (Ar+)

A Comparison of Various Types of Lesion

In addition to being used in eye surgery, lasers are also employed to check eye functions. For example, a grid is projected on the retina in order to check a person’s vision. The patient’s responses pertaining to these patterns helps the ophthalmologist determine whether there is any damage to the patient’s retina. Scanning laser ophthalmoscopy is a procedure in which the retina is scanned by a laser and imaged. For scanning retinas, the following types of laser are suitable: Ar+ (488 nm, 514 nm), HeNe (633 nm) and infrared (780-805 nm) lasers.

In dermatology, predominantly argon, CO2 and Nd:YAG lasers are used. Thanks to its low depth of penetration, the argon laser is preferred for treatment of superficial changes to skin, such as benign moles. Melanin absorbs the wavelength of the Ar+ laser, while the upper layers of the skin are penetrated by the laser beam without being affected at all. In the process, laser energy is collected within melanin, enabling the entire layer of skin to be lifted off.

Laser beams in the visual and infrared spectral range of wavelengths of up to 3 µm can be coupled into glass optical fibers. They even allow inaccessible areas, such as blood vessels, the stomach and other body cavities, to be explored. In otolaryngology, collimation of argon laser beams in flexible and rigid optical observation systems, i.e., endoscopes, enable specific sinuses to be specifically treated.

Overall, laser technology provides convincing precision performance for touch-free operation. Moreover, coup-ling of laser beams in an optical fiber considerably facilitates the transport of light, and is gaining importance in surgical microscopy.

Inte

nsity

[W/c

m²]

Length of interaction time [s]

4

Fiber coupler laser systems provide obvious advantages not only in medical therapy, but also in diagnostic applica-tions and metrological procedures.

Modern dentistry resorts to diagnostic procedures using confocal laser scan-ning microscopy (CLSM) for routine checkups of cavities. The optical system of a reflected light microscope ensures linear scanning of a tooth using the laser beam emitted by an argon laser (488 nm). The depth of beam penetra-tion is 100 µm and is reflected and absorbed by the tooth enamel. The reflected beams pass through a beam guide through a pinhole and into a detector. Afterwards, the data are evaluated.

In optical metrology, laser technology has enabled countless new procedures, such as interferometry, laser anemome-try, holography and triangulation.

Measurement of flow conditions, such as particle image velocimetry (PIV), is a measurement method based on laser anemometry. Laser light conducted to indicator particles is scattered by them within a medium. With the help of a laser light section (1 mm thick), which is produced by a corresponding lens, information concerning the direction of propagation and the flow velocity can be obtained via a CCD camera.

Another application for lasers is direct examination of particles using fluores-cence activated cell sorting (FACS).

A liquid stream contains cell complexes that result from antigen-antibody reactions. These complexes consist of antibodies that are marked by a fluores-cent dye and that are bound to mole-cules or proteins. In this method, the complexes are counted, and characteri-zing properties, such as cell size and nucleus size are analyzed. This analysis is performed by hydrodynamic focusing; i.e., the coupled cells are lined up and conducted along a focused laser beam of the corresponding wavelength. Once the electrons of the fluorescent dye are stimulated and de-energized, the dye gives off photons, which are registered by a detector. The number of photons is equivalent to the quantity of bound antibodies and cells.

Another method for using fiber coupler laser systems is ellipsometry. This is a non-destructive optical measurement procedure for material research and surface diagnostics. In this method, the change in polarization is examined. Laser light in the visible spectral range along with a specific polarization state is focused on a sample of material. The size of the resulting phase shift enables

Confocal Laser Scanning Microscope(CLSM) Leica TCS SP5

Application Areas Info Tel.: +49 (0)551 69 35-0

conclusions to be drawn about the properties of a material, such as its layer thickness and refractive index. The basis for evaluation is a mathematical model that defines the dependence of the reflection coefficient on the parameters of the sample. A major application for this method is examination of layer systems in the semi-conductor industry. for evaluation is a mathematical model that defines the dependence of the reflection coefficient on the parameters of the sample. A major application for this method is examination of layer systems in the semi-conductor industry.

There are many good reasons for choosing fiber coupler laser systems from LINOS,such as:

• Physical separation of equipment from the laser source and operation lenses (overcomes lack of space and prevents annoying excessive noise)• One laser system purchased can be shared by several labs • Flexible detector thanks to fiber- coupled analyzers

Summary

There is an extremely wide variety of possibilities for using laser systems and fiber coupler systems, both for existing applications and those bound to emerge in the future.

Focus

The fiber coupler system developed and patented by LINOS has been designed for the visible spectral range (250 mW cw max. entrance power, at 405 nm 50 mW cw) and is ideal for transmitting linear polarized light.

5

lens in the Z direction via a laterally attached set collar using a fine adjust-ment screw. The counter pressure required for this is generated by a pressure spring. The lens mount can be secured in its position by two setscrews. This adjustment mechanism allows the high transmission of the fiber coupler system to be attained again even after exchanging the fiber guide. To prevent the setting of the fine adjustment screw from being accidentally changed, access to this screw is sealed off by a protective plug. Furthermore, the setscrews for securing the lens mount are not access-ible using the adjustment tools.

Two Allen wrenches with a size of 2 mm (for fine adjustment screws) and 1.5 mm (for screws with conical spring washers) are needed to adjust the fiber coupler. To attach the fiber coupler to a laser using M3 fillister-head screws, a 2.5-mm Allen wrench is required.

Fiber Coupler Lens

The main component of the fiber coup-ler is the lens that is used to focus the laser beam input on the fiber core. Two major criteria must be met in selecting the appropriate fiber coupler lens:

• The image-side numeric aperture (NA) of the lens must not be larger than the NA of the fiber.• The diameter of the focused laser beam must not be greater than the mode field diameter (MFD) of the fiber.

Special requirements on fiber coupler systems for multi-line applications, in other words, simultaneous operation for several different wavelengths in the particular spectral range, give rise to problems with chromatic aberration (different focal lengths for different wavelengths). For this reason, LINOS uses an achromatic lens, which has (nearly) the same focal length for the various wavelengths, in its fiber coupler.

Precision Mechanics and Optics

The most important element of fiber coupler systems is the fiber coupler. This is designed to couple laser light with high efficiency and the correct direction of the polarization axis in the optical fibers. For this purpose, the LINOS fiber coupler incorporates a lens and is equipped with diverse adjustment elements.

Construction of the LINOS Fiber Coupler

The LINOS fiber coupler is designed as a tilting coupler; i.e., the fiber coupler lens and the fibers are permanently connec-ted to one another and are tilted around the beam axis by three fine adjustment screws (arranged at less than 120°). The restoring force needed is generated by three fillister-head screws with six conical spring washers, which are each offset by 60° from the fine adjustment screws, which means the spring washers are located opposite from the screws. Tilting the fiber coupler lens and fiber light guide with respect to the laser beam causes a lateral shift in the focus on the end of the fiber. The resulting reduction ratio in the leverage allows single-mode fibers with small core diameters to be precisely adjusted. Using the three screws that generate restoring force, the position set can be permanently fixed by increasing the force. The tilting adjust-ment range is 2° from the parallel basic position.

In addition to being able to be tilted, the fiber coupler lens can be shifted toge-ther with the fiber in the x and y direc-tion perpendicularly to the beam axis. This can also be accomplished using the two fine adjustment screws whose counterpressure can be adjusted by two spring bolts with thumbscrews. Here, the contact points are on a conical plane so that inadvertent tilting while shifting the lens and fiber in the X or Y direction can be virtually ruled out.

Dimensions of the Fiber Coupler

Shifting the X-Y direction of the fiber coupler lens and fiber changes the angle at which light enters the fiber. The posi-tion set can be permanently secured using an additional locking screw. The fiber coupler lens can be shifted together with the fiber by ±1 mm.

As the LINOS fiber coupler has been specially designed for use with polari-zation-maintaining fibers, it is possible to optimally couple the linear polari-zation of the laser in one of the two main fiber axes (in this case, the slow axis) by turning the fiber along with the fiber coupler lens by 360° around the beam axis. In the process, centering is accomplished by using the adjustment elements for X-Y shifting.

Moreover, the LINOS fiber coupler has been designed so that the fiber cable can be detached. This is important, for example, if you need to disconnect both components for transportation. More-over, this enables a defective fiber cable to be exchanged independently of the fiber coupler. For this reason, the fiber cables have an FC male connector on the fiber coupler end. This connector can be attached to the matching FC female connector on the fiber coupler.

To optimize coupling, the fiber coupler offers the possibility of changing the distance between the lens and the fiber by ± 0.5 mm from the center position. This is done by shifting the mounted

Connector for fiber connector

Fiber Couplers Introduction

6

Please specify the laser beam and fiber parameters so that we can select just the right lens for you.

On your order, please indicate the following:

• Letter/number combination according to the order number codes for fiber collimators• If desired, indicate your specific requests and requirements

Information on Lens Selection

The focal length of the lens used in the LINOS fiber coupler must be adapted to the desired fiber, taking the laser wave-length and laser beam diameter into consideration. Only in this manner is it possible to attain a high coupling efficiency near the theoretical maximum.

Information on Connector Choice

When placing your order, please be sure to specify whether the FC female connector for the fiber coupler is to be designed for a fiber with an 8° polish (FC8/PC8) or with a 0° polish (FC0/PC0).

For more information on fiber polishes, please refer to the section on Fiber Configuration.

Order Code Numbers for Fiber Collimators

Type

Con

nect

or

Wav

elen

gth

(s)

[nm

]

Beam

dia

met

er

[mm

]

NA

of

Fibe

r

FIC50 XYZ: fiber couplerwith XYZ adjustment

FC8/PC8: connector for FC8 and PC8 (fiber with 8° polish)

FC0/PC0: connector for FC0 and PC0 (fiber with 0° polish)

Individual wavelengths between 400 and 700 nm orwavelength ranges: BVIS (400-450) or:BVIS (400-640)VIS (450-640)RVIS (630-700)

0.6 to 2.0 0.08 to 0.12

Practical Example

FIC50 XYZ - FC8/PC8 - VIS - 0.8 - 0.11Fiber coupler with XYZ adjustment

Connector for FC8 and PC8,for VIS range, for 0.8 mm beam diameter and fiber with a numeric aperture of 0.11

Fiber Couplers Choice of Lenses and Order Numbers

7

Light Transmission

The technology of transmitting light in a long, narrow dielectric by means of total reflection has been known for quite some time. John Tyndall demonstrated in 1854 that one can enclose light in a thin stream of water and guide its trans-mission along the stream. Soon after-wards, glass tubes and later filaments made of silica glass were used to demon-strate this effect even more impressively. After the laser was invented in 1960, the scientific community recognized the advantages that could be gained by transmitting information by light instead of by an electrical current. In the course of the past 40 years, optical fiber techno-logy has undergone such tremendous development that we now are familiar with three areas of application: direct transmission of images and illumination, fiber optics for communication techno-logy and novel types of sensor. The following details exactly how light is transmitted by optical glass fibers and the particularities of polarization-main-taining fibers from a theoretical view-point.

How Light Transmission Works

Transmission of light in a glass fiber uses the principle of total (internal) reflection (see Fig. 1). The fiber itself consists of a core and a cladding, where nCR > nCL applies to its refractive index. Typical values for an optical fiber are nCR ≈ 1.62 and nCL ≈1.52. Usually, both the core and the cladding are made of silica glass (SiO2), and the core may be doped with germanium in order to raise the core’s refractive index. It is also possible to dope the cladding with a different material to lower its refractive index. In practice, optical fibers are fabricated with a protective coating made of a synthetic material, called a jacket, to protect the cladding from damage. This coating does not have any optical effect.

with an outer diameter of approx. 100 to 250 µm. Because of its relatively thick core, the fiber is rugged, making it easy for light to enter. Depending on the angle of incidence, hundreds of different beam paths or modes exist (of which three are shown in Fig. 2), over which light can propagate all along the core. In this case, we call this a multi-mode fiber (MM fiber) in which every mode corres-ponds to a different travel time. Beams with a greater angle of incidence travel further than do those that propagate along the axis. As the reflexion at the boundary layer between the core and the cladding is considerable, beams of the former type – a greater angle of incidence – take more time than do those of the latter type to travel from one end of the fiber to the other. This effect is called modal dispersion.

Fig. 1: Prinziple of light trans- mission in a glass fiber

Fig. 2: Optical fiber structures and refractive index profile

Fibers Functional Principle

That is why it is not considered in the following descriptions. The schematic diagram in Fig. 1 shows the input end of a fiber (without a jacket), with a meridional beam that propagates inside the core. On account of the total reflec-tion, a maximum value of Θmax of the angle Θi is produced. Below this value, the beam traveling inside the core hits the wall of the core at the critical angle Θc and is totally reflected. Beams that

hit the end surface of the fiber at an angle greater than qmax reach the interior wall at a larger angle than Θc. Therefore, they are only partially reflec-ted by the surface and thus absorbed within the cladding. Hence, Θmax defines the half angle of the entrance cone of the fiber within which all beams guided by total reflection lie. If the entrance side of the fiber is located in air (NA ≈1), the numeric aperture NA of the fiber is yielded by the critical angle of total reflection.

Fig. 2 outlines the three most commonly used optical fiber structures with their respective core and cladding. In the fiber shown in Fig. 2a, the core is relatively thick; the refractive indices of the core and cladding are constant over the cross-section of the fiber. This is the so-called step index fiber, which has a homogeneous core with a dia meter of 50 to 150 µm or larger and a cladding

Θi

Θt ΘcCore

Cladding

d

d

d

Fig. 2a

Fig. 2b

Fig. 2c

n

n

n

8

A result of the different travel times is a broadened rectangular pulse at the end of the fiber, which was initially sharply defined.

Differences in the travel time can be substantially reduced by gradually decreasing the refractive index of the core towards the cladding (see Fig. 2b). In this case, beams do not propagate in a zigzag manner through the fiber, but rather spirally around the center axis. As the refractive index is greater near the axis than at the edges, beams that have shorter distances to cover are slowed along the axis. Beams that propagate spirally near the cladding move faster on longer paths. On account of their refrac-tive index gradients, these fibers are called gradient index fibers, or GRIN fibers for short.

The last and best solution for minimizing modal dispersion is to choose the smallest possible core diameter that provides just enough space for a single mode in which beams propagate parallel to the central axis (see Fig. 2c). For this reason, these fibers are called single-mode fibers, or SM fibers for short. Their typical core diameters ranging from 2 to 9 µm enable modal dispersion to be eliminated for the most part.

If fibers for light transmission are used, the lowest possible attenuation is usually required to keep the amount of light lost along the travel path as low as possible. For fibers used in data trans-mission in the field of telecommunica-tions, this amount is approx. 0.1 dB/km.

Polarization-maintaining Fibers

In an ideal single-mode fiber with circular geometry, two (degenerated) modes with orthogonal polarization states and identical propagation con-stants β can move in the X- and Y-direc-tion of the fiber. These are designated as LP01

x and LP01y modes so the term

“single-mode fiber” is not quite correct in the narrower sense. However, super-position of the LP01

x and the LP01y modes

as one mode (LP01 mode) is generally understood. The effect of external stress (e.g. such as that resulting from motion or deflection) causes the fiber to be-come birefringent; i.e., the difference Δβ results between the two propagation constants βx and βy (Δβ = Δx - Δy); this difference grows as the amount of anisotropy increases at the point of intersection of the axes. The slightest external interference is all it takes to result in collimation of the two degene-rated modes. Therefore, for linearly polarized coupled light, an elliptical polarization state is yielded just after a short beam path; this condition is dependent primarily on external inter-ference.

By using the birefringence in a fiber, it is therefore possible to transmit linear polarized light so that it still remains linear polarized at the output of the fiber. For this reason, these special single-mode fibers are called polariza-tion-maintaining fibers, or PM fibers for short.

The PM fibers used by LINOS are sub-classified according to a “bowtie” and a “PANDA” structure. Inside the fiber core, targeted application of mechanical stress produces stress birefringence in two different refractive indices in the X and Y direction.

For this purpose, elements that apply stress are incorporated into the fiber cladding. These are known as “stress-applying parts,” or SAPs for short. The stress applied to the fiber core results in the manufacturing process when the fiber is drawn from a preform. Com-pared with the fiber cladding, the SAPs in the preform have a higher heat expan-sion coefficient α (αSAP ≈3·10-6 K-1, αCL ≈ 5·10-7 K-1). For this reason, they shrink considerably more as the drawn fiber cools off, thus producing mechanical stress. The heat expansion coefficient of the SAPs can be increased, for example, by doping the basic material SiO2 with boron. Although the refractive index changes slightly as a result of doping, the SAPs viewed under a microscope can hardly be told apart from those on a cladding that consists of non-doped SiO2.

The shapes of SAPs differ depending on the manufacturer and use of a fiber, where usually only two different types are manufactured. In Fig. 3a (see next page), the bowtie structure is depicted in which the SAPs are arranged in an arced manner around the fiber core. In Fig. 3b (see next page), the PANDA structure of a polarization-maintaining fiber is schematically shown. This designation is derived from the similarity of the structure to the face of a panda bear.

9

Because of the birefringent properties of the fiber core, the different refractive indices of the two main axes can be defined as for birefringent solid bodies. In the direction of the SAPs – in other words, in the direction parallel to the field of tension, the fiber core has a higher refractive index so that this axis is also referred to as the “slow axis.” The main axis perpendicular to the slow axis is thus called “fast axis” (see Fig. 3). Theoretically, it is irrelevant in which of the two axes the linear polarized light has to be coupled in order to retain the polarization state of the light. In practice, collimation is usually done on the slow axis as it shows a lower sensitivity to bending than does the fast axis.

Fig. 3a: Fiber with a bowtie structure Fig. 3b: Fiber with a Panda structure

By the term “fiber configuration,” we mean the fabrication of a complete optical fiber cable from a raw fiber. Essentially, this involves assembling a jacket on the fiber, mounting the con-nectors and polishing the fiber ends.

LINOS offers standard fiber cable con-figurations in lengths of 2 and 3 m. These are encased in a flexible coil made of stainless steel in order to protect the fiber bundle from external damage during use.

LINOS offers the following types of protective jacket:

Order Number 900 KV3 SD5 XX

Jacket Hytrel jacketØ 0.9 mm

PVC jacketKevlar reinforcedØ 3.0 mm

Stainless steel jacketØ 5.0 mm

nojacket

Drawing PVC jacket

Fiber Kevlar

Fiber

Stainless steelcoil

Fibers Functional Principle

Fibers Fiber Configuration

Slow axis

Fast axis SAPs

Cladding

Core

Slow axis

Fast axis SAPs

Cladding

Core

10

The most important components for fabricating fiber cables are the connec-tors that are mounted on both ends of the fiber.

Once the connectors have been mounted on the fiber, the ends are polished to produce the optical quality of the end surfaces and the geometric shape of the ferrule and fiber. Several polish options are available to choose from. The most common types of polish are shown in the schematic diagram. Each circle shows the front part of the ferrule (2.5 mm Ø) with the fiber bonded in the center.

The simplest polish is FC polish in which the fiber is polished perpendicu-larly to its axis (PC stands for “flat connector”). FC/PC polish, which means the surface is polished in a slightly spherical manner, is commonly used if the connectors are butted in order to connect two fiber cables (PC stands for “physical contact”). Unlike the PC polish, the APC polish (APC: “angled physical contact”) means that the fiber end is polished at an 8° angle to prevent interfering back reflection, as in the light source. LINOS offers so-called AFC polish (AFC: “angled flat connector”) as its standard polish. On the one hand, this polish excels in sup-pressing back reflection thanks to its 8° angle and, on the other hand, its flat end surface ensures high reproducibility for exchanging fibers. Here, it is impor-tant that the spacing between the edge of the angleand the fiber core be main-tained as accurately as possible. Only in this way can the high transmission of fiber coupler systems be maintained when fibers are exchanged, without having to refocus the lens.

For polarization-maintaining fibers, the slow axis must be parallel to the end surface of the fiber and parallel to the anti-twist lock.

You will find the order number codes for LINOS fibers on the next page.

Order Number

FC0 PC0 PC8 FC8XX

Type ofconnector

FC FC/PC Angled FC/PC(APC)

Flat Angled FC/PC (AFC)

Ferrule

Back reflection (approx. in dB)

-30 -50 -60 -60 n.n.

LINOS offers the following choice of fiber polishes:

FC

Angled FC/PC (APC)

FC/PC

Flat Angled (AFC)

,Anti-twist lock,wide key (2.14 mm)

11

FibersOrdering Information

Choice of Fiber

LINOS offers standard configured fiber cables in lengths of 2 m and 3 m. On request, different lengths between 1 m and 10 m can be supplied. When ordering, please specify the wavelength range in which the operating range you need lies. To protect the fiber ends from damage, they are covered by non-detachable protective caps. .

Ambient Conditions

Storage temperature -20 to +60 °COperating temperature +15 to +40 °CHumidity Non-condensing

On your order, please indicate the following:

• Letter/number combination according to the order number codes for fibers• If desired, indicate your specific requests and requirements

Order Code Numbers for Fibers

Fibe

r ty

pe

Wav

elen

gth(

s)[n

m]

Fibe

r le

ngth

[m]

Prot

ectiv

e ja

cket

l

Con

nect

or

inpu

t

Con

nect

or

outp

ut

FIBSM: single-mode fiber, FIBPM: polarization-maintaining fiber

Wavelength ranges:BVIS (400-450) orBVIS (400-640)VIS (450-640)RVIS (630-700)

1 to 10(2 and 3 m = standard lengths)

SD5KV3900XX

FC0FC8PC0PC8XX

FC0FC8PC0PC8XX

Practical Example

FIBPM - VIS - 2 - SD5 - FC8 - FC8 Polarization-maintaining fiber for the 450-640 nm range,2 m length, with stainless steel 5 mm Ø jacket, both ends with FC connectors that have an AFC polish.

12

Fibe

r ty

pe

Wav

elen

gth(

s)[n

m]

Fibe

r le

ngth

[m]

Prot

ectiv

e ja

cket

l

Con

nect

or

inpu

t

Con

nect

or

outp

ut

FIBSM: single-mode fiber, FIBPM: polarization-maintaining fiber

Wavelength ranges:BVIS (400-450) orBVIS (400-640)VIS (450-640)RVIS (630-700)

1 to 10(2 and 3 m = standard lengths)

SD5KV3900XX

FC0FC8PC0PC8XX

FC0FC8PC0PC8XX

Notes

13

• Fast and trouble-free use• Highly compact design• Low insertion loss• Low back reflexion• For the visible spectral range (400-700 nm)• Achromatic lenses • Excellent beam quality with low wavefront deformation (diffraction-limited imaging)

To collimate the divergent beam emitted by a fiber, the end surface of the fiber must be positioned exactly in the focu-sing plane of the lens. The diameter of the collimated beam ds and the angle of divergence α depend on the focal length f of the lens, on the core dia-meter dk and on the numeric aperture NA of the fiber (see Fig. 4 on beam collimation).

α

α

Fig. 4: Beam collimation

LINOS offers two different versions of fiber collimators:

Fiber collimator FOC10 Z has a diameter of 10 mm and a length of 19.5 mm. The lens can be optimized to meet specific customer requirements by using the focusing key supplied with the collimator.

Fiber collimator FOC12 has a diameter of 12 mm and a length of 50 mm. The FOC12 is available only in conjunc-tion with a fiber optic cable (see the order number codes for fiber collimation systems) as beam collimation and the position of the beam axis to the housing are specially adjusted to the particular fiber. Here, a concentricity of ≤ ± 0.5 mrad and an excentricity of ≤ ± 150 µm are attained. When polarization-main-taining fibers are used, the direction of polarization of the light emitted is identified by a red dot on the housing.

Fiber collimator FOC10 Z Dimensions: FOC10 Z

Dimensions: FOC12Fiber collimator FOC12

Fiber Collimators Functional Principle

,

female connector for fiber

female connector for fiber

14

Information on Selecting Lenses

The focal length of the lenses installed in fiber collimators must be specially adapted to the fibers used, taking into account the laser wavelength and the desired beam diameter. Only in this way is it possible to optimally collimate the divergent light emitted from the fiber.

Information on Choosing Connectors

When ordering, please specify whether the FC connector of the fiber collimator is to be designed for a fiber with an 8° polish (FC8/PC8) or with a 0° polish (FC0/PC0). You will find additional infor-mation on fiber polishes on page 11.

Type

Con

nect

or

Wav

elen

gth(

s)[n

m]

Beam

dia

met

er

[mm

]

NA

of

the

fiber

FOC10 Z: fiber collimation with Z-adjustment

FC8/PC8: connector for FC8 and PC8 (fibers with 8° polish)

FC0/PC0: connector for FC0 and PC0 (fibers with 0° polish)

Individual wavelengths between 400 and 700 nm or wavelength ranges:BVIS (400-450) orBVIS (400-640)VIS (450-640)RVIS (630-700)

0.6 to 2.0 0.08 to 0.12

Practical Example

FOC10 Z - FC8/PC8 - 473 - 1.0 - 0.10Fiber collimator with Z-adjustment

Connector for FC8 and PC8, operating wavelength 473 nm,1.0 mm beam diameter, for a fiber with a numeric aperture of 0.10

Fiber Collimators Ordering Information

Ambient Conditions

Storage temperature -20 to +60 °COperating temperature +15 to +40 °CHumidity Non-condensing

On your order, please indicate the following:

• Letter/number combination according to the order number codes for fibers• If desired, indicate your specific requests and requirements

15

Fiber Coupler Systems

In addition to supplying the individual components presented, LINOS also offers you the option of ordering complete fiber coupler systems that are a combination of a fiber coupler unit, fiber cable and fiber collimator.

Example of a Fiber Coupler SystemWith an input beam diameter of 0.8 mm, the following specifications are attained for a fiber coupler system with a polarization-maintaining fiber:

Transmission

Wavelength range(BVIS, VIS, RVIS) > 65 %

Individual wavelength from the ranges > 75 %

Polarization contrast > -20 dBThis corresponds to > 100:1

Fiber with fiber coupler, fiber and fiber collimator(Holder for the fiber collimator not included in the standard equipment supplied)

You will find the order number codes for a complete fiber coupler system on the following page.

Fiber Coupler Systems Functional Principle

16

FCS

Fibe

r ty

pe

Wav

elen

gth(

s)[n

m]

Fibe

r le

ngth

[m]

Prot

ectiv

e ja

cket

l

Con

nect

or in

put

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FCS = Fiber Coupler System

FIBSM: single-mode fiber,

FIBPM: polariza-tion-maintaining fiber

Individual wavelength between 400-700 nm,Wavelength ranges:BVIS (400-450) orBVIS (400-640)VIS (450-640) RVIS (630-700)

1 to 10 (2 and 3 m = standard lengths)

SD5KV3900XX

FC0FC8PC0PC8XX

FC0FC8PC0 PC8XX

FIC50 XYZ 0.6 to 2.0

FOC12FOC10 Z

0.6 to 2.0

Practical Example

FCS - FIBPM - 633 - 2 - SD5 - FC8 - FC8 - FIC50 XYZ - 0.8 - FOC12 - 0.8

Fiber coupler system for an operating wavelength of 633 nm, polarization-maintaining fiber, 2 m length, with 5 mm Ø stainless steel jacket, FC connectors that have an AFC polish on both ends, fiber coupler for 0.8 mm input beam diameter, fiber collimator with an 0.8 mm output beam diameter.

Fiber Coupler Systems Ordering Information

On your order, please indicate the following:

• Letter/number combination according to the order number codes for fibers• If desired, indicate your specific requests and requirements

17

Accessories

LINOS fiber optic components can also be combined with its well-known optomechanical systems, such as the LINOS microbench, nanobench and tube mounting system C.

Photo:Examples of fiber optic systems adapted to LINOS systems:

Tube Mounting System CMicrobenchNanobench(from left to right)

The following accessories are available for these equipment combinations:

Connecting Tube C30 FC 06 7056

• Mounting flange without lens• For attachment of fibers with FC connectors• Outer diameter of 30 mm for mounting on microbench

Connecting Tube C30 FC with Lens 06 7058

• Mounting flange with centerable lens • Planoconvex lens; f = 4 mm, Ø = 5 mm • Assembly otherwise as for 06 7056• Centering range ± 0.5 mm• Thread mount of lens can be axially adjusted• Matching tube wrench, size 13 mm, 06 5233 902 (not included)

Female connector for FC fiber connector

Setscrew3x120°

Accessories Adapters for LINOS Systems

Female connector for FC fiber connector

18

FC Fiber Adapter 0° 06 7054

• Mounting flange with lens• For attachment of fibers with FC connectors• Outer diameter of 25 mm for assembly on Microbench Mounting plate 25, Holder 25 or Centering mounting plate 25 (for X-Y adjustment) and translation stage (for adjustment of the X-axis)

FC Fiber Adapter 3.5° 03 8857

• Mounting flange without lens• For use with FC / APC and AFC connectors• Compensates for beam deflection that occurs when FC / APC and AFC connectors are used• C-Mount female thread• Outer diameter of 30 mm for assembly on in Microbench Mounting plate 30 or Holder 30

FC Fiber Adapter N FC 06 7023

• Mounting flange without lens• For attachment of fibers with FC connectors• Outer diameter of 12.5 mm for assembly on Mounting plate N 12.5 of the LINOS Nanobench

Set of Tools for FIC50 XYZ 17 3010

• Consists of: - Gauge - Gauge chart - Allen wrench with grip and 2 mm wrench size - Allen wrench with grip and 1.5 mm wrench size

Female connector for FC fiber connector

Female connector for FC fiber connector

FC / APC connector(not included)C

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LINOS Photonics GmbH & Co. KGKönigsallee 23D-37081 GoettingenGermany

Phone +49 (0)551 69 35-0Fax +49 (0)551 69 35-166E-mail sales@linos.deInternet www.linos-katalog.de

LINOS Photonics Inc.459 Fortune BoulevardMilford, MA 01757-1745USA

Phone +1 (508) 478-62 00Fax +1 (508) 478-59 80E-mail info@linos-photonics.comInternet www.linos.com

LINOS Photonics Ltd.2 Drakes Mews, Crownhill Milton Keynes, Bucks MK8 OER UK

Phone +44 (0) 19 08 262-525Fax +44 (0) 1908 262-526E-mail sales@linos.co.ukInternet www.linos.com

LINOS Photonics SARL90, Avenue de Lanessan69410 Champagne au Mont d'OrFrance

Phone +33 472 52 04 20Fax +33 472 53 92 96E-mail info-fr@linos.comInternet www.linos.com