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In the world of lasers, few systems seemed to gain traction with users as quickly as the early fiber laser systems. Thats not a surprise. Fiber lasers represented a substantial leap beyond what was possible with earlier technologies, like the first pumped diode systems, or with established methodologies like the CO2 laser. But what, exactly, is a fiber laser?
For engineers and scientists, a fiber laser is a device where an optical fiber is doped with rare-earth elements, like:
But for non-engineers and the less-than-scientifically-savvy, that explanation leaves much to be desired. So, lets explain.
Traditionally, gas sits at the core of a laser. A CO2 laser, for example, uses carbon dioxide. That allows for an infrared beam with wavelength bands centering on 9.4 and 10.6 micrometers.
That beam level can cut a variety of materials. CO2 lasers are also useful in medical situations, such as soft-tissue surgery or dermatology.
A fiber laser swaps out gas with a silica glass optical fiber. That fiber is then doped when a tiny bit of one of the rare-earth elements is added to it. The atoms that make up the laser medium are then housed within that rare-earth-doped fiber. The emitted photons are confined within the doped fiber core.
Fiber lasers have a principal advantage over their rivals stability. A fiber laser produces a beam inside the core, so beam delivery doesnt require sensitive or complex optical equipment.
A normal laser, on the other hand, either uses an optical fiber to move the laser beam or uses mirrors to bounce it around. While either approach works, both require highly precise alignment. Conventional lasers are sensitive to impact and movement. Once things misalign, a specialist has to set things right.
A fiber laser has no such sensitivity. It can handle the knocks, bumps and vibrations of any assembly line. Additionally, confining a laser beam to the doped fiber core keeps the beam compact and straight. That, in turn, allows for small and precise focusing. As a general rule in lasers, the smaller the dot created by the beam, the more effective it is for cutting.
A fiber laser is also power-efficient. It can convert nearly 100% of the input it receives into the beam, thus limiting the power converted into heat energy. This helps protect the fiber from heat damage or fracture. All of this adds up to a robust laser requiring next to no maintenance.
Fiber lasers can produce various wavelengths, opening them up to numerous industrial tasks marking, cleaning, drilling and texturing, to name a few. Youll find them in many industries, such as medicine, telecommunication, automotive, dental and electronics.
Fiber lasers offer the following advantages for marking, cleaning and other laser applications:
Fiber lasers have a wide range of power outputs, making them ideal for various applications. Here are a couple of their uses.
Laser marking or engraving uses a concentrated light beam to create a permanent mark on a surface, such as a barcode, logo or other means of identification. Ytterbium-doped laser fibers with a 1,064-nanometer emission wavelength are well-suited for laser marking.
They can be manual or automated, creating durable, high-contrast marks on metal and plastic surfaces. These fibers can easily adjust to fast production cycles, making them a popular choice for original equipment manufacturers and suppliers.
Laser cleaning is the process of removing rust, paint, oxide and other debris from metal surfaces. Fiber lasers make this process more efficient, effectively cleansing metal surfaces of these substances. Additionally, you can customize and automate the cleaning process for different production line conditions and requirements.
Fiber lasers have a long history. Elias Snitzer first invented them in . However, the first commercial models didnt appear on the market until the late s. And Telesis was there.
Our first model was the Ytterbium Fiber Laser. It used an approach that had gained acceptance in communications, but we recognized it could be adapted for use in marking materials. It was an earth-shattering development. This new laser marking style was the most advanced technology of its era.
Its robust nature contributed to its primary breakthrough. The Ytterbium Fiber Laser produced run times of 20,000 hours and higher. So successful did the technology prove that it is still widely used in surface marking today.
We then developed the Vanadate laser system. This system uses a crystal made of vanadate (a compound of the chemical element Vanadium) with fiber-coupled diodes. The Vanadate Laser produces a high-quality beam, creating extraordinarily fine lines on a remarkably wide range of materials.
Today, Telesis manufactures and sells several varieties of ytterbium Q-switched fiber lasers for product marking. Our powerhouse models are the Fiber Series. These lasers have average power levels of 10-100 watts. They use a metal-sheathed fiber optic cable to deliver a high-power beam.
Recently, we released an entirely new product line aimed at reducing costs while boosting speed throughput for manufacturing customers. The idea behind the Dual-Head Pulsed Fiber Laser Marking System is simple let one person using just one personal computer operate multiple lasers simultaneously.
Despite that simplicity, the Dual-Head system maintains the beam quality of Telesis fiber lasers, plus a 100,000-hour mean time between failures (MTBF) diode reliability. The Dual Head system is entirely air-cooled and powered from a single-phase power outlet.
Most importantly, the Dual-Head system allows for an easy transition from more traditional numeric code printing to state-of-the-art 2D Matrix printing that can encode large amounts of traceability data.
Major manufacturers are seeing the benefit. The Dual Head System has been deployed and tested by leading manufacturers, such as Harley-Davidson® Motorcycles and Nissan® Motor Co. Ltd.
In the rapidly changing world of fiber laser technology, no company can rest on its laurels not even a company like Telesis. Our latest breakthrough has only recently entered production the 100-Watt Fiber Laser system.
The engineering community has long been aware of 100-watt fiber lasers extraordinary power. However, folks in the C-suite know laser systems with that power level have been too pricey for all but a few. Thats why we tasked our world-class team of scientists and engineers with creating an affordable version of such a system.
Remarkably, they have done so.
Our new high-power fiber laser makes deep (0.3 millimeters) marks in a single pass! That speed and depth make the 100-Watt laser perfect for applications like creating vehicle identification number (VIN) marks in the automotive industry or part identifiers for avionics.
Manufacturers are excited. We sold three of these new fiber laser systems while they were still being tested!
Next?
With the breakthrough of the 100-Watt Fiber Laser, its tempting to say the industry has reached its pinnacle. What more could anyone possibly expect from a fiber laser?
We intend to find out.
Our engineers know that the robust nature and precise beams of fiber laser machines indicate a future of faster, less expensive marking devices.
In fact, they have a few surprises up their sleeves already. Stay tuned.
If youre looking to reap the benefits of fiber laser technology, choose Telesis Technologies, Inc. as your provider. Offering a large variety of permanent marking and traceability solutions, were ready to deliver a fiber laser marking system that speaks to your needs.
With the highly versatile and adaptable Telesis Fiber Series Laser Marking System, you can enjoy:
This solution comes in a compact, modular package, making it simple to integrate into your operations. The Telesis Fiber Series Laser Marking System is ideal for plastic and metal processing applications, offering direct, efficient and precise part marking. It also doesnt require water cooling.
Whether you work in automotive, aerospace, food and beverage, medical device manufacturing or another industry requiring laser marking, Telesis Technologies is a fiber laser marking machine supplier you can trust. To learn more about upgrading your product marking applications with our innovative fiber laser technology, talk to one of our experts today.
Discuss your part marking needs with an expert today // Download the Telesis Product Guide
A fiber laser (or fibre laser in Commonwealth English) is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium. They are related to doped fiber amplifiers, which provide light amplification without lasing.
Fiber nonlinearities, such as stimulated Raman scattering or four-wave mixing, can also provide gain and thus serve as gain media for a fiber laser.[citation needed]
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An advantage of fiber lasers over other types of lasers is that the laser light is both generated and delivered by an inherently flexible medium, which allows easier delivery to the focusing location and target. This can be important for laser cutting, welding, and folding of metals and polymers. Another advantage is high output power compared to other types of laser. Fiber lasers can have active regions several kilometers long, and so can provide very high optical gain. They can support kilowatt levels of continuous output power because of the fiber's high surface area to volume ratio, which allows efficient cooling. The fiber's waveguide properties reduce or eliminate thermal distortion of the optical path, typically producing a diffraction-limited, high-quality optical beam. Fiber lasers are compact compared to solid-state or gas lasers of comparable power, because the fiber can be bent and coiled, except in the case of thicker rod-type designs, to save space. They have lower cost of ownership.[1][2][3] Fiber lasers are reliable and exhibit high temperature and vibrational stability and extended lifetime. High peak power and nanosecond pulses improve marking and engraving. The additional power and better beam quality provide cleaner cut edges and faster cutting speeds.[4][5]
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Unlike most other types of lasers, the laser cavity in fiber lasers is constructed monolithically by fusion splicing different types of fiber; fiber Bragg gratings replace conventional dielectric mirrors to provide optical feedback. They may also be designed for single longitudinal mode operation of ultra-narrow distributed feedback lasers (DFB) where a phase-shifted Bragg grating overlaps the gain medium. Fiber lasers are pumped by semiconductor laser diodes or by other fiber lasers.
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Many high-power fiber lasers are based on double-clad fiber. The gain medium forms the core of the fiber, which is surrounded by two layers of cladding. The lasing mode propagates in the core, while a multimode pump beam propagates in the inner cladding layer. The outer cladding keeps this pump light confined. This arrangement allows the core to be pumped with a much higher-power beam than could otherwise be made to propagate in it, and allows the conversion of pump light with relatively low brightness into a much higher-brightness signal. There is an important question about the shape of the double-clad fiber; a fiber with circular symmetry seems to be the worst possible design.[6][7][8][9][10][11] The design should allow the core to be small enough to support only a few (or even one) modes. It should provide sufficient cladding to confine the core and optical pump section over a relatively short piece of the fiber.
Tapered double-clad fiber (T-DCF) has tapered core and cladding which enables power scaling of amplifiers and lasers without thermal lensing mode instability.[12][13]
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Recent developments in fiber laser technology have led to a rapid and large rise in achieved diffraction-limited beam powers from diode-pumped solid-state lasers. Due to the introduction of large mode area (LMA) fibers as well as continuing advances in high power and high brightness diodes, continuous-wave single-transverse-mode powers from Yb-doped fiber lasers have increased from 100 W in to a combined beam fiber laser demonstrated power of 30 kW in .[14]
High average power fiber lasers generally consist of a relatively low-power master oscillator, or seed laser, and power amplifier (MOPA) scheme. In amplifiers for ultrashort optical pulses, the optical peak intensities can become very high, so that detrimental nonlinear pulse distortion or even destruction of the gain medium or other optical elements may occur. This is generally avoided by employing chirped-pulse amplification (CPA). State of the art high-power fiber laser technologies using rod-type amplifiers have reached 1 kW with 260 fs pulses [15] and made outstanding progress and delivered practical solutions for the most of these problems.
However, despite the attractive characteristics of fiber lasers, several problems arise when power scaling. The most significant are thermal lensing and material resistance, nonlinear effects such as stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS), mode instabilities, and poor output beam quality.
The main approach to solving the problems related to increasing the output power of pulses has been to increase the core diameter of the fiber. Special active fibers with large modes were developed to increase the surface-to-active-volume ratio of active fibers and, hence, improve heat dissipation enabling power scaling.
Moreover, specially developed double cladding structures have been used to reduce the brightness requirements of the high-power pump diodes by controlling pump propagation and absorption between the inner cladding and the core.
Several types of active fibers with a large effective mode area (LMA) have been developed for high power scaling including LMA fibers with a low-aperture core,[16] micro-structured rod-type fiber [15][17] helical core [18] or chirally-coupled fibers,[19] and tapered double-clad fibers (T-DCF).[12] The mode field diameter (MFD) achieved with these low aperture technologies [15][16][17][18][19] usually does not exceed 2030 μm. The micro-structured rod-type fiber has much larger MFD (up to 65 μm [20]) and good performance. An impressive 2.2 mJ pulse energy was demonstrated by a femtosecond MOPA [21] containing large-pitch fibers (LPF). However, the shortcoming of amplification systems with LPF is their relatively long (up to 1.2 m) unbendable rod-type fibers meaning a rather bulky and cumbersome optical scheme.[21] LPF fabrication is highly complex requiring significant processing such as precision drilling of the fiber pre-forms. The LPF fibers are highly sensitive to bending meaning robustness and portability is compromised.
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In addition to the types of mode locking used with other lasers, fiber lasers can be passively mode locked by using the birefringence of the fiber itself.[22] The non-linear optical Kerr effect causes a change in polarization that varies with the light's intensity. This allows a polarizer in the laser cavity to act as a saturable absorber, blocking low-intensity light but allowing high intensity light to pass with little attenuation. This allows the laser to form mode-locked pulses, and then the non-linearity of the fiber further shapes each pulse into an ultra-short optical soliton pulse.
Semiconductor saturable-absorber mirrors (SESAMs) can also be used to mode lock fiber lasers. A major advantage SESAMs have over other saturable absorber techniques is that absorber parameters can be easily tailored to meet the needs of a particular laser design. For example, saturation fluence can be controlled by varying the reflectivity of the top reflector while modulation depth and recovery time can be tailored by changing the low temperature growing conditions for the absorber layers. This freedom of design has further extended the application of SESAMs into modelocking of fiber lasers where a relatively high modulation depth is needed to ensure self-starting and operation stability. Fiber lasers working at 1 μm and 1.5 μm were successfully demonstrated.[23][24][25][26]
Graphene saturable absorbers have also been used for mode locking fiber lasers.[27][28][29] Graphene's saturable absorption is not very sensitive to wavelength, making it useful for mode locking tunable lasers.
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In the non-mode locking regime, a dark soliton fiber laser was successfully created using an all-normal dispersion erbium-doped fiber laser with a polarizer in-cavity. Experimental findings indicate that apart from the bright pulse emission, under appropriate conditions the fiber laser could also emit single or multiple dark pulses. Based on numerical simulations the dark pulse formation in the laser may be a result of dark soliton shaping.[30]
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Multi-wavelength emission in a fiber laser demonstrated simultaneous blue and green coherent light using ZBLAN optical fiber. The end-pumped laser was based on an upconversion optical gain media using a longer wavelength semiconductor laser to pump a Pr3+/Yb3+ doped fluoride fiber that used coated dielectric mirrors on each end of the fiber to form the cavity.[31]
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Three fiber disk lasersAnother type of fiber laser is the fiber disk laser. In such lasers, the pump is not confined within the cladding of the fiber, but instead pump light is delivered across the core multiple times because it is coiled in on itself. This configuration is suitable for power scaling in which many pump sources are used around the periphery of the coil.[32][33][34][35]
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Applications of fiber lasers include material processing, telecommunications, spectroscopy, medicine, and directed energy weapons.[36]
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For more information, please visit fiber laser cutting machine.