Author: Fiber-MART.COM

Variable optical attenuator (VOA) has a wide range of applications in optical communication, and its main function is to reduce or control the optical signal.

The basic characteristics of fiber optic network should be Variable, especially with the application of DWDM transmission systems and EDFA in optical communication, it must be carried out in a plurality of optical signal on the transmission channel gain flattening or equalization, channel power in the optical receiver. The side to be dynamic saturation control, optical networks also need to control for other signals, making the VOA become indispensable key components. In addition, VOA also can be combined with other optical communication components and this pushed itself to the characteristics of the high-level module.

In recent years, there appeared many technologies on manufacture of variable optical attenuator, including mechanical VOA, magneto-optical VOA, LCD VOA, MEMS VOA, thermo-optic VOA and acousto-optic VOA.

Mechanical VOA

The principle is to use a stepper motor drag neutral gradient filter, its output optical power at a predetermined attenuation rule change when the different positions of the light beam passes through the filter, so as to achieve the purpose of adjusting the amount of attenuation. There is also a mechanical polarized optical attenuator. Its basic principle is that the light beam emitted from the ingress port reflected by the reflection sheet to the port, the the reflector coupling efficiency between the two ports by the inclination angle of the reflection sheet to the control, enabling adjustment of the light attenuation. The inclination of the reflection sheet from a variety of different mechanisms to control. Mechanical type optical attenuator is more traditional solutions, so far, the VOA application in the system most used mechanical method to achieve attenuation. The type of optical attenuator with mature technology, optical properties, low insertion loss, polarization dependent loss, without temperature control, etc.; disadvantage is that the larger, more complex structure components, the response rate is not high, it is difficult to automate the production is not conducive to integration.

Magneto-optical VOA

Magneto-optical VOA is the use of some of the substances in the magnetic field is shown by the changes in optical properties, such as magnetic rotation effect (Faraday effect) can also be achieved attenuation of the light energy, so as to achieve the purpose of adjusting the optical signal. The magneto-optical effect of the material and in combination with other techniques, you can create a high performance, small size, high response and the structure is relatively simple optical attenuator. This is LLL device using discrete technology to produce the optical attenuator to be a further development of the field.

LCD VOA

Utilizing a liquid crystal refractive index anisotropy in the liquid crystal VOA shows birefringence. When an external electric field is applied, the orientation of the liquid crystal molecules are rearranged, will result in the change in its transmission characteristics. The type of attenuation can be achieved by light intensity change of the type of voltage control is applied to the two electrodes in the liquid crystal. The liquid crystal optical attenuator VOA can achieve the miniaturization and high response. But at the same time the liquid crystal material into a larger loss, the production process is relatively more complex, in particular, is influenced by environmental factors, its advantage is a low cost, there are commercial batch.

MEMS VOA

MEMS is the technology of the new applications in this area, After several years of development, the MEMS chip production process has become more mature, a strong impetus to the application of the MEMS optical attenuator. Optical network applications, MEMS technology-based products also have the obvious advantage on price and performance. MEMS VOA has been very mature, and mass production and large-scale application. Because of yield problems, in terms of price also facing challenges In addition, micro-electro-mechanical components, reliability is sometimes less than ideal. The early MEMS VOA using laser welding, into a larger device, and the production efficiency is low, and high assembly costs. Currently, the market also introduced a MEMS VOA plastic technology, a good solution to this problem.

Thermo-optic VOA

Thermo-optic VOA mainly using some of the material changes in the optical properties of temperature field characteristics, such as temperature changes caused by the thermo-optical refractive index change. According to the structure of the different, can be divided into two categories, leak-and open-light type VOA. Thermo-optic VOA due to heating, cooling device is relatively complex, a function of the mathematical relationship between the temperature field photoconductive medium refractive index is complex and difficult to accurately quantify and control, especially the longer response time hindered its application in modern optical communication .

Acousto-optic VOA

The basic principle is to use the cyclical strain, resulting in a periodic variation of the refractive index, equal to create a phase grating for the acousto-optical crystal in the generated under the action of ultrasonic waves, and so can be modulated using the raster beam. Some companies have already claimed to have developed the acousto-optical crystal variable attenuator (called the AVOA). It is understood that the acquisition of the acousto-optic crystal material is no problem, but at this stage of the total cost is high, about 4-5.

Conclusion:

Variable optical attenuator is one of important optical devices in the optical communication system. Over the years, it has been stuck at a mechanical level. Because its size is not conducive to integration, it is generally only suitable for single-channel attenuation. With the development of DWDM system, as well as market the flexibility to upgrade reconfigurable optical add-drop multiplexer (ROADM) potentially huge demand, there need more channels and small size variable optical attenuator array, in particular the integrated VOA product. Traditional mechanical methods can not solve these problems. With the development of fiber optic network, VOA’s development trends are: low cost, highly integrated, fast response time as well as integration of hybrid with other optical communication devices.

Bigger is much better, right? Or so many people believe. Beginners in fiber optic technology are often confused with why optic attenuators should reduce light intensity. Aren’t we using amplifiers to improve the signal electricity? The fact is that too much light can overload a fiber optic receiver. Optical fiber attenuators are needed when a transmitter delivers too much light, such as when a transmitter is very close to the receiver.

So how exactly does a Fiber Attenuator Work?

Attenuators usually works by absorbing the sunshine, such as a neutral density thin film filter. Or by scattering the sunshine such as an air gap. They should not reflect the light since that could cause unwanted back reflection within the fiber system. Another type of attenuator utilizes a length of high-loss optical fiber, that operates upon its input optical signal power level in such a way that it is output signal power level is less than the input level. The power reduction are done by such means as absorption, reflection, diffusion, scattering, deflection, diffraction, and dispersion, etc.

What’s the Most Important Feature Should a Fiber Attenuator Have?

The most crucial spec of an attenuator is its attenuation versus wavelength curve. Attenuators should have the same impact on all wavelengths used in the fiber system or at least as flat as possible. For instance, a 3dB attenuator at 1500nm should also lessen the concentration of light at 1550nm by 3dB or as close as possible, this is also true inside a WDM (Wavelength Division Multiplexing) system.

Different Types of Attenuators

There are two functional kinds of fiber attenuators: plug style (including bulkhead) and in-line. A plug style attenuator is utilized like a male-female connector where attenuation occurs inside the device, that’s, on the light path from one ferrule to another. Included in this are FC fiber optic attenuator, LC attenuator, SC attenuator, ST attenuator and much more. An in-line attenuator is connected to a transmission fiber by splicing its two pigtails.

The key of operation of attenuators are markedly different simply because they use various phenomena to lower the power of the propagating light. The easiest means would be to bend a fiber. Coil an area cable several times around a pencil while measuring the attenuation with a power meter, then tape this coil. Then you definitely got a primitive but working attenuator.

Most attenuators have fixed values which are specified by decibels (dB). They’re called fiber optic fixed attenuator. For instance, a -3dB attenuator should reduce intensity of the output by 3dB. Manufacturers use various light-absorbing material to attain well-controlled and stable attenuation. For instance, a fiber doped with a transition metal that absorbs light in a predictable way and disperses absorbed energy as a heat.

Variable optical attenuator is also available, but it is usually a precision instrument utilized in making measurements. From fiber-mart.com, you can get the best Variable Attenuators Instrument

Optical attenuator is a very important fiber optic passive components. It’s an indispensable device for fiber CATV. So far the market has formed four series that are fixed-step, variable, continuously variable and intelligent optical attenuator.

Types of Optical Attenuators

A. Displacement Optical Attenuator

As we all know, when the two sections of optical fiber connection, must meet a really high accuracy, in order to make the optical signal a smaller loss transmission previously. Conversely, when the fiber to help make the appropriate alterations in the precision, you can control the amount of attenuation. Displacement-type optical attenuator is based on this principle, the intention of the fiber within the butt, the appearance of certain dislocation. The sunshine energy loss, in order to achieve the purpose of a controlled amount of attenuation, the displacement-type optical attenuator is divided into two types: the lateral displacement type optical attenuator, the axial displacement of the optical attenuator. The lateral displacement from the optical attenuator is a classical method, due to the magnitude from the lateral displacement parameters in the micron level, so generally do not have to produce a variable attenuator is used only for producing fixed attenuator, and the use of welding or stick connection, there is still a sizable market, the benefit of high return loss, generally more than 60 dB. Axial displacement type optical attenuator by mechanical means as long as the process design of two optical fibers a certain distance with the objective, is possible attenuation. This principle is mainly employed for producing fixed optical attenuator and some small variable optical attenuator.

B. Thin-film Optical Attenuator

This attenuator is created while using principle of sunshine in the reflected light concentration of the top of metal thin film film thickness. When the thickness from the metal thin film deposited around the glass substrate is bound, made of a set optical attenuator. Different attenuation can be obtained if inside a different thickness of a disk-shaped metallic thin wax glass substrate, metallic thin film, so that inserted within the optical road to different thicknesses so that you can alter the intensity of the reflected light within the optical fiber inserted obliquely deposited Cover made of the variable attenuator.

C. Attenuation-sheet Optical Attenuator

Attenuation the chip type optical attenuator directly fixed attenuator through an absorption characteristic in the end surface of the optical fiber or even the optical path to attain the reason for the attenuation from the optical signal, this process can not simply be used to produce a fixed optical attenuator can also be used to produce the variable optical attenuator.

Applications of Optical attenuators

A set optical attenuator fixed amount of attenuation of the optical road to the sunshine energy is principally used for its excellent temperature characteristics. Within the commissioning from the system, widely used in analog optical signal through the corresponding period of optical fiber attenuation or reduce the margin from the optical power the relay station may also be used to prevent saturation from the optical receiver; optical test instrument calibration scaling. For different line interface, you can use different fixed attenuator; if the interface is really a pigtail type available pigtail type optical attenuator welded towards the optical path between the two sections of fiber; If you are debugging the machine connector interface converter or inverter-type fixed attenuator.

In practical applications often require attenuation quantity of the optical attenuator could be changed using the user needs. Therefore, a wider range of applying the variable attenuator. For instance, EDFA, CATV optical system design margin of the particular product is not quite the same, the optical power margin of the system BER assessment, to prevent the receiver is saturated, it should be inserted within the system variable optical attenuator, another , fiber optics (such as a power meter or OTDR) measurement, calibration will also make use of the variable attenuator. From the perspective of market demand, on the one hand, the optical attenuator development toward miniaturization, serialization, low price direction. However, due to the common type optical attenuator, optical attenuator is development direction toward high-performance, intelligent optical attenuator, high return loss optical attenuator.

Cutting Machine:

Cutting Machine is used for cutting out parts of articles from layers of cloth card webs or knitted fabric. The technically possible depth of cutting of the layer depends on the design of the cutting machine and on the thickness and properties of the fabrics. Cutting machines may be movable or stationary. The machine is shifted manually relative to the layer along lines drawn on the top card web. The development of apparel sector has led to the invention of various fabric cutting machines. Industrial cutters and cutting machines have led to better efficiency and precision in our work. The invention of these gadgets has reduced considerable efforts in the cutting process of different types of fabrics. Although there are different types of cutting machines used to cut fabrics and the most common type of cutting machines are given below:

Different Types of Fabric Cutting Machine:

According to the operating process, the Cutting Machine can be classified into three types.

Such as- ManualSemi- Automatic

Automatic / Computerized

1) Manual Cutting Machine:

Hand Scissors.

2) Semi-Automatic Cutting Machine:

Straight knife of Cutting Machine.

Round Knife Cutting Machine.

Band Knife Cutting Machine.

Die Cutting Machine.

Notcher Machine.

Drill Machine.

3) Computerized Cutting Machine:

Knife Cutting Machine.

Laser Cutting Machine.

Water Jet Cutting Machine.

Airjet Cutting Machine.

Ultrasonic Cutting Machine.

Plasma Torch cutting Machine

Fiber laser cutting machine is a currently popular laser cutting type which adopts fiber laser source to fulfil perfect cutting effect. Fiber lasers are a type of solid state laser that is rapidly growing within the metal cutting industry.

Fiber technology utilizes a solid gain medium, as opposed to a gas or liquid. The “seed laser” produces the laser beam and is then amplified within a glass fiber. With a wavelength of only 1.064 micrometers, fiber lasers produce an extremely small spot size (up to 100 times smaller compared to the CO2) making it ideal for cutting reflective metal material.

Fiber laser source can outputs high-powered laser beam that focuses on the surface of materials, vaporizing or melting the focused area instantaneously. Controlled by numerical and mechanical system, the laser head is moved and laser spot is also changed accordingly to achieve automatic cutting with fast speed and high accuracy. Fiber laser cutter has been developed into a highly precise laser cutting type, widely used in metal parts processing industries.

Fiber laser cutting machine is able to process a wide range metal materials, including stainless steel, carbon steel, alloy steel, aluminum, galvanized sheet, copper, silver, gold and so on, for which different fiber laser sources could be opted regarding to the features of metals.

In addition to sheet metals cutting, fiber laser cutting machine also could process profiled metals and steel pipes. A set of steel pipe cutting system can be configured to the machine to broaden its cutting capacity. The cutting edge is neat and smooth to meet high industrial requirement.

Fiber laser has higher energy conversion rate that can reach up to 30%, saving operation and maintenance cost.

Fiber lasers are designed with semiconductor modular and redundancy, and there is no optical lens in resonant cavity. So no need to spend much time starting and adjusting the machine before cutting work, which is incomparable among traditional laser machines.

Protective lens is configured in fiber laser head to protect focus lens and reduce parts consumption.

Laser head won’t touch the materials directly so as not to scratch the materials and ensure quality cutting effect.

Fiber laser produces the smallest kerf and thermal area, which keeps the cutting stability and avoid deformation of the material.

02mm/min cutting accuracy and fast cutting speed markedly increases the work efficiency of metal parts manufacturing.

Fiber laser cutting machine works in a safe and environmentally friendly way. Little pollution and noise will be produced and workshop environment is well protected.

As a professional fiber laser equipment manufacturer, we are specialized in fiber laser cutting machine and fiber laser marking/engraving machine manufacturing and technical service. For more details about fiber laser cutting machine selection and operation, please contact us for customized laser solution to upgrade your business.

Fabric lasers are a type of solid state laser with best beam quality.The beam diameter of the fiber is smaller than on CO2 resulting in finer details in work.Fiber laser cutting machines are 100 times stronger than gas laser machine. Due to its set of great features Fiber Laser Cutting Machines find their use in wide range of applications, 5 such uses are listed below:

Medical devices: Medical field cannot imagine its present and future without fiber laser cutting machines. From cutting small components for really complex medical devices to laser surgeries performed on human tissues laser cutting is used at every step in the medical field.

Jewelry: Jewelry manufacturers were in desperate need of a reliable and cost effective technology which can provide precise cutting, superior edge quality, ability to cut complex shapes and high production ability in less time. A fiber laser cutting machine fulfilled all these requirements and is widely used today in this industry.

Automotive: The automotive industry is huge and developing every second. Use of Fiber Laser cutting machines makes it easier for this industry to cope with everyday advancement in design and technology. These machines are excellent for cutting smaller and complicated components used in automobiles, also cuts hydro formed parts, which are metal parts formed in 3D shapes, with great accuracy. These machines are not only specialized in cutting metal but a couple of other materials too, like cloth for airbags. It leaves no fraying while cutting the cloth, unlike conventional processes which use blades.

Electronics: Silicon is the most important material used on PCB’s in semiconductor, microelectronics industries. As electronic devices are getting more and more compact with each passing day, PCB’s are bound to get smaller. In such a case Fiber laser cutting machines are ideal to cut thin and delicate material like silicon.

Textile Industry: Fabric laser cutting machines are gaining popularity around textile industries these days because of their extreme accuracy, clean cuts, sealed fabric edges to prevent fraying and capability to cut different kinds of fabric like polyester, silk, cotton, leather, nylon and neoprene.

In spite of being a newer development in the area of lasers, Fiber Laser Cutting Machines established themselves pretty well against traditional cutting machines. fiber-mart.com is very well known the manufacturer of Fiber laser cutting machines situated at Navi Mumbai. Scantech is popular for its technical innovations in various fields of custom laser applications.