Fiber Lasers: Everything You Need to Know
Fiber lasers are everywhere in the modern world. Due to the different wavelengths they can generate, they are widely used in industrial environments to perform cutting, marking, welding, cleaning, texturing, drilling and a lot more. They are also used in other fields such as telecommunication and medicine.
Fiber lasers use an optical fiber cable made of silica glass to guide light. The resulting laser beam is more precise than with other types of lasers because it is straighter and smaller. They also have a small footprint, good electrical efficiency, low maintenance and low operating costs.
If you want to learn everything you need to know about fiber lasers, keep reading.
When Was the Fiber Laser Invented?
Elias Snitzer invented the fiber laser in 1961 and demonstrated its use in 1963. Serious commercial applications only emerged in the 1990s, however.
Why did it take so long? The main reason is that fiber laser technology was still in its infancy. For example, fiber lasers could only emit a few tens of milliwatts whereas most applications require at least 20 watts. There was also no means of generating high-quality pump light, as laser diodes did not perform as well as today.
Here are some of the key moments in the history of fiber laser technology, going back as early as 1917 when Albert Einstein established its foundations.
1917 – Stimulated emissions are discovered (Albert Einstein).
1957 – The theoretical framework for the laser is developed (Gordon Gould).
1960 – The first laser—a ruby laser—is constructed (Ted Maiman).
1960 – Continuous-wave laser beams are generated for the first time.
1960 – The term “fiber optics” is coined (Narinder Kapany).
1961 – Optical modes in glass fibers are invented (Elias Snitzer).
1962 – Q-switching, a technique to generate pulsed laser beams, is demonstrated (Robert W. Hellwarth and R.J. McClung).
1963 – The first fiber laser is demonstrated (Elias Snitzer).
1964 – A method is discovered to remove impurities from glass fibers, and hence limit light loss (Charles Kao and George Hockham).
1988 – The first double-clad fiber laser is demonstrated (Elias Snitzer).
1990 – The watt barrier is broken with a 4W erbium-doped fiber laser.
2004 – The single-mode silica fiber laser and amplifier is invented (David N. Payne).
Today, important advances are still being made in fiber laser technology, making it more efficient, powerful and accessible. Some of the most upcoming applications include laser cleaning and laser texturing, which can replace polluting technologies and help make the world greener.
What Are the Types of Fiber Lasers?
Generally speaking, fiber lasers can be categorized using the following criteria:
Laser source: Fiber lasers vary according to the material with which the laser source is mixed. Some examples include ytterbium-doped fiber lasers, thulium-doped fiber lasers, and erbium-doped fiber lasers. All these types of lasers are used for different applications because they produce different wavelengths. .
Mode of operation: Different types of lasers release laser beams differently. Laser beams can either be pulsed at a set repetition rate to reach high-peak powers (pulsed fiber lasers), as is the case with “q-switched”, “gain-switched” and “mode-locked” lasers. Or, they can be continuous, meaning that they continuously send the same amount of energy (continuous-wave fiber lasers).
Laser power: Laser power is expressed in watts and represents the average power of the laser beam. For example, you can have a 20W fiber laser, a 50W fiber laser, and so on. High-power lasers generate more energy faster than low-power lasers.
Mode: The mode refers to the size of the core (where light travels) in the optical fiber. There are two types of modes: single-mode fiber lasers and multi-mode fiber lasers. The core diameter for single-mode lasers is smaller, typically between 8 and 9 micrometers, whereas it is larger for multi-mode lasers, typically between 50 and 100 micrometers. As a general rule, single-mode lasers convey laser light more efficiently and have a better beam quality.
Fiber lasers can be categorized in many other ways, but the categories mentioned here are the most common. Follow these links if you want to see examples of fiber lasers integrated into products:
