Pulsed Fiber Lasers

Differentiated from DPSS lasers, instead of a crystal, these fiber laser systems utilize a doped fiber optic cable as the gain medium. Typically, they are doped with rare-earth elements, such as erbium (Er), ytterbium (Yb), or neodymium (Nd), just like the crystals used in most DPSS laser systems. These lasers provide pulsed output, as opposed to CW lasers, which emit a continuous output beam.

Fiber lasers offer several advantages over traditional DPSS lasers (e.g., Nd:YAG lasers). Some of these advantages derive from the geometry of the fiber optic itself, namely, the innate ability to have an extremely long single-mode optical cavity. This geometry produces either extremely high-power single-mode fiber lasers exhibiting unprecedented brightness or extremely narrow band lasers with near-perfectly single-frequency output. Another advantage is that the fiber medium is flexible, which makes it easier to deliver the beam exactly where you need it. This ability can be highly advantageous when dealing with complex geometries and tight spaces. Typically, fibers exhibit a complex temperature-dependent polarization evolution, except for example, if utilizing polarization-maintaining fibers or Faraday rotators. However, these solutions are typically not compatible with nonlinear polarization rotation mode locking.

Since the fiber optic acts as a gain medium, several kilometers long in some cases, high-power fiber lasers benefit from the high optical gain and can provide much higher output powers compared to some other laser types. The extremely high surface area to volume ratio provides the inherent ability to efficiently remove heat generated, allowing continuous output of kilowatt levels of output power. The waveguide properties of the optical fiber mitigate thermal distortion, producing high-quality, near-diffraction-limited or better optical beam output (i.e., better beam quality). It should be noted that fiber lasers are different than fiber-coupled lasers. Fiber-coupled lasers simply have the beam output coupled into a fiber, as opposed to free-space output, and do not share all the same benefits as detailed above. However, fiber lasers do rely on one or more fiber-coupled laser diodes to pump the gain medium. Fiber amplifiers, lacking the ‘cavity’ to enable lasing, also rely on fiber-coupled diode pumps.

Fiber laser technology tends to provide a more compact system when compared to typical solid-state or gas lasers with a comparable power level, because of the ability of the fiber to be coiled up, allowing a considerable amount of gain media to be confined in a small space without all the traditional optical components. Compared to Ti:Sapphire lasers, for example, the fiber laser cost of ownership is generally lower since they are air-cooled and require little to no maintenance, requiring less supporting laser equipment. These lasers are also highly reliable, operating with high stability in high temperature and vibration prone environments.

Nanosecond Fiber Lasers

Nanosecond pulsed lasers emit optical pulses in the nanosecond duration.  A nanosecond (ns) is a unit of time equal to one thousand-millionth of a second, one billionth of a second, or 10^–9 seconds.  Optical pulses with a pulse duration in the nanosecond range are required for many applications, including material processing, distance measurements, and remote sensing.

Picosecond Fiber Lasers

Picosecond pulsed lasers emit pulses with a duration in the picosecond range.  A picosecond is a trillionth of a second, or 10^-12 seconds.  To be considered an Ultrafast Laser, the pulse duration of the laser needs to be 10ps or less.  At a given pulse energy, the peak power of the laser increases as the pulse width gets shorter.  Therefore, a picosecond laser will have a much higher peak power than a longer nanosecond or millisecond pulsed laser.

Femtosecond Fiber Lasers

Femtosecond pulsed lasers  emit optical pulses with a duration below 1 picosecond.  A femtosecond (fs) is one quadrillionth of a second or 10^–15 seconds.  Lasers that produce less than 10 picoseconds pulses belong to the category of Ultrafast Lasers or Ultrashort Pulse Lasers.  Ultrafast Lasers are ideal for the non-thermal or cold ablation of any material, including metals, ceramics, polymers, composites, coatings, glass, plastics, diamonds, and PET.

Applications

Our pulsed fiber lasers are used in a wide range of high precision biophotonic and industrial applications including multi-photon microscopy, optogenetics, fluorescence lifetime, 3D scanning, LiDAR, materials processing applications like micromachining, surface treatment, thin film removal, welding, and many more!

Let Us Help

In conclusion, if you have any questions, or if you would like some assistance, please contact us here. Furthermore, you can email us at info@rpmclasers.com to talk to a knowledgeable Product Manager. Alternatively, you can also use the filters on this page, or check out our ‘How to Select a Pulsed Laser‘ section of our ‘Pulsed Lasers’ page to assist in narrowing down the selection pulsed fiber lasers for sale. Finally, head to our Knowledge Center with our Lasers 101 page, Blogs, Whitepapers, and FAQ pages for further, in-depth reading.

Suggested Reading

Check out this blog, titled “Advantages of Two-Photon Microscopy Utilizing Femtosecond Fiber Lasers,” for further reading on the benefits of pulsed fiber lasers compared to older and more bulky & expensive Ti:Sapphire lasers.

To learn about pulsed fiber lasers for Laser Induced Breakdown Spectroscopy, check out this blog, titled “Fiber Lasers for Industrial LIBS Applications.”

Read this whitepaper, titled “Single-Frequency Fiber Lasers for Doppler LIDAR,” for further reading about pulsed fiber lasers for Doppler LIDAR.