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Laser light can be used in different industries, from entertainment, scientific endeavors, and surgery, to advanced and heavy duty industrial manufacturing.

Fiber Lasers 101

What is a Laser?

“Laser” is an acronym for Light Amplification by Stimulated Emission of Radiation. Put more simply, a laser converts energy into light, which is then amplified through optics, before focusing that light into a high energy beam. Laser light differs from normal light in that it can be collimated, or made less prone to dispersion, and then focused to greatly increase its energy density. There are many kinds of lasers and the uses of laser light include range from entertainment, scientific endeavors, and surgery, to advanced and heavy duty industrial manufacturing.

All lasers share a basic set of components. Laser start with a gain medium which is used to amplify the power of light — laser gain mediums include gases, dyes, diodes, crystals, and optical fibers. An energy source, either an electrical current or a source of light, is then used to pump the gain medium. Once the necessary energy is generated reflective materials known as partial and total reflectors control the laser output which is then adjusted and focused as needed for the application at hand.

Laser Parameters


Laser Wavelength Table


Laser Wavelength

Measured in nanometers (nm) or microns (µm), the wavelength of a laser is the distance between successive crests of the light wave. Laser wavelengths typically range from deep ultraviolet to mid-infrared (IR) and are visible to the human eye in the range from ~400 to ~700 nm.  

Wavelength is a critical consideration for many applications because materials often differ dramatically in how they absorb the energy of light. Materials absorb some portion of a laser beam’s energy and reflect the rest — the balance between the two can necessitate the use of a different laser wavelength. Wavelength is also of critical importance for advanced and scientific applications including microscopy, optical trapping, and ultrasonics.

Near IR wavelengths of approximately 1000 nm are used as a starting point, particularly for processing of metals. This is because near IR lasers offer higher powers, are less complex, and are often more cost-effective. Most metals absorb light in the near IR or visible range efficiently. Even metals with high IR reflectivity, such as aluminum and copper, are predominantly processed by near IR lasers which overcome material reflection with higher power densities.

Various polymers, ceramics, glass, and other non-metals are often processed by lasers with wavelengths from mid-infrared to deep ultraviolet. Clear polymers and glass are actually transparent or nearly transparent to near IR light, allowing the majority of near IR light through without being absorbed. As a result, materials that readily absorb near IR light can be processed through a polymer or glass layer.


Laser Power

Also referred to as average power, laser power is measured in watts (W). A laser’s average power represents how much energy is delivered to the target material over a period of time. Laser power requirements vary by many orders of magnitude for different applications. Many sensing, data processing, telecom, medical, or scientific applications utilize powers from a few milliwatts to tens of watts. Non-metal processing applications typically demand anywhere from a few watts to a few hundred watts of average power. Metal fabrication applications demand powers anywhere from hundreds of watts, in the case of some microprocessing applications, to dozens or more kilowatts, in the case of thick metal cutting and welding applications.


Peak power table for various laser modes of operation.


Laser Mode of Operation

Lasers can emit a continuous beam of light to output a steady stream of average power – this mode is referred to as Continuous Wave (CW) and is the most common laser mode of operation. Lasers can also be used in a pulsed mode of operation. Pulsed lasers are characterized by pulses per second (repetition rate), the total energy of the laser pulse (pulse energy), the highest power achieved by the pulse (peak power, and the length of each pulse (pulse duration).

Like CW lasers, pulsed laser output over time is represented as average power. Pulsed lasers, even when their average power matches that of a CW laser, affect targeted material differently. Pulsed lasers are often used to process parts while minimizing the thermal impact on the surrounding material or when higher peak power is necessary. Long pulse quasi-continuous wave (QCW) lasers utilize pulses measured in milliseconds with high peak powers to emulate CW laser processing with less heat input and with a lower power laser. Nanosecond and ultrafast (picosecond/femtosecond) lasers take advantage of extremely short pulses for microprocessing applications where excessive heat input is not acceptable or when extremely high peak powers are required.

Generally speaking, CW lasers offer the highest average powers and, as a result, the fastest processing speeds. There are many considerations to be made when deciding between a CW laser and a pulsed laser, but balancing throughput with part quality is often the most important. Many applications, such as sheet metal cutting, benefit from a high-power CW lasers for greatly increased cutting speeds and have no need for flawless edge quality. When cutting stacks of ultra-thin foils, however, nanosecond and ultrafast pulsed lasers are typically used to ensure excellent edge quality and reduce or eliminate negative heat effects.


Example of multi-mode and single-mode laser beam profiles.

Left: a multi-mode beam profile with a larger spot size. Right: a single-mode beam profile with a smaller spot size.


Laser Spot Size & Beam Quality

When a laser beam comes into contact with its target material it forms an area of laser light referred to as a spot. Spot size, typically measured in µm, is a critical factor in determining how a laser interacts with its target. Spot size can be controlled in a variety of ways, including using different delivery fibers and focusing lenses, changing the distance between the beam delivery and the target, and using longer or shorter wavelengths.

Decreasing the spot size makes more efficient use of a laser’s power by concentrating the beam’s energy in a smaller area. Higher energy density is useful for increasing processing speeds by decreasing the time it takes for a laser beam to pierce the material. Small spot sizes are also essential for a variety of microprocessing applications and for parts that require fine features. For many applications like structural welding, however, increasing spot size is optimal for processing a wider area and reducing the required beam travel.

Beam quality, typically measured in M2 for single-mode lasers (typical spot size: 20 to 50 µm) and Beam Parameter Product (BPP) for multi-mode lasers (typical spot size: 100+ µm), is an important and complex laser parameter that, in practice, represents how much a laser beam can be focused. Lower M2 and BPP values correspond with higher beam qualities. A beam quality of M2 = 1 means that the beam experiences no divergence and is considered perfect. Although this is not quite achievable with actual devices, industrial fiber lasers can reliably achieve beam qualities of M2 =< 1.1. For applications that require strongly focused beams like cutting, drilling, and welding, higher beam qualities improve processing speeds and qualities. Some applications, like wide area laser heat treatment and cleaning, do not require particularly high beam qualities, instead benefitting from less focused laser energy.

What are Fiber Lasers?

Fiber lasers guide light through an optical fiber cable made of silica glass, which serves as the gain medium, and are pumped via electrical current. This method of delivery, combined with efficient conversion of electricity into light, makes fiber lasers a significantly more practical solution in many cases than legacy lasers like CO2 lasers or alternative technologies like disk lasers. Free of complex optics, frequent service requirements, or consumables, fiber laser technology is significantly easier to integrate and has had a revolutionary impact on laser-based manufacturing, medical applications, and scientific endeavors.

Feature comparison table between fiber laser and other laser mediums.

The unique properties of optical fiber make it an ideal active gain medium and laser resonator material. Flexible, easy to handle, and able to support a variety of lengths, fiber's huge surface to volume aspect ratio facilitates heat removal and helps to avoid thermal lensing. Fibers of different types, compositions, and core diameters can be spliced to construct complex optical systems combining the pump sources, optical amplification, and beam delivery fiber without the need for free space optics and their inherent risks of contamination, damage, and misalignment.

IPG Fiber Laser Technology

Our unique technology platform allows IPG lasers to have higher output powers and superior beam quality at a lower cost that can be achieved by any other competing laser technology. Our proprietary designs are based around innovative pumping techniques and high-performance components perfected by IPG over decades of intense investment and innovations. The cornerstones of IPG fiber laser technology are our cladding side-pumping technique and distributed single-emitter diode pumping architecture


Diode Pumping Technology


The cladding side-pumping technique and distributed single-emitter diode pumping architecture are the cornerstones of IPG's fiber laser technology.


Best-in-class diode pump technology leverages our vast telecommunication industry experience and technology investment. Our single-emitter diodes are manufactured using telecom-proven technology and processes, and each wafer is qualified to rigorous telecommunication industry standards, which sets IPG apart from alternative industrial pump products using short-lived diode bars and bar-stack technologies. As a result, IPG single emitter diodes offer an order of magnitude higher pumping brightness and up to double the power efficiency of bar-stack pumps. Single-emitter pumps are able to use simple water or even forced air cooling, as opposed to bars-stacks which require expensive, unreliable, and complex microchannel coolers using high pressure deionized water.

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Side Pumping Technology


A schematic diagram illustrating the side-pumping technique developed by Dr. Valentin Gapontsev and Dr. Igor Samartsev


Fiber lasers must couple and collect the light from laser diodes in order to create a collimated laser output. The output of IPG single-emitter diodes is collected into fibers with core diameters as small as 100 microns. Using the side-pumping technique developed by Dr. Valentin Gapontsev and Dr. Igor Samartsev, the light from many pump diodes is efficiently coupled into the cladding of an active gain fiber. The pump light undergoes multiple reflections within the cladding while frequently intersecting the single-mode core where the light is absorbed and re-emitted by rare-earth ions. This elegant mechanism converts diode light into fiber laser light with exceptional efficiency.

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Learn More About IPG Fiber Lasers

From milliwatts of power to more than one hundred kilowatts, from UV to mid-IR, and from continuous wave to femtosecond pulses, IPG lasers are powered by industry-leading technology to optimize results across a wide variety of applications including materials processing, medical operations, and scientific endeavors.

Learn more about how the widest range of fiber lasers and fiber laser capabilities can maximize productivity and make more possible.

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