{"id":13964,"date":"2022-04-27T16:37:33","date_gmt":"2022-04-27T13:37:33","guid":{"rendered":"https:\/\/fractory.com\/?p=13964"},"modified":"2024-01-26T13:49:14","modified_gmt":"2024-01-26T11:49:14","slug":"fibre-lasers-explained","status":"publish","type":"post","link":"https:\/\/fractory.com\/fibre-lasers-explained\/","title":{"rendered":"Fibre Lasers – Working Principles, Applications & More"},"content":{"rendered":"

Lasers have been around for a long time but their use in commercial applications is quite recent. It took engineers a while to strengthen laser capabilities to a point where they could compete with traditional manufacturing methods in terms of cost, time and ease of use.<\/p>\n

Fibre laser technology, for instance, was first developed back in the 60s. Back then, this technology was still in its nascent phase. Only in the 1990s did it become fit for commercial use. Since then, the technology has come a long way in terms of its applications and efficiency. In the 60s it was possible to only generate a few tens of milliwatts, today we have fibre lasers that can generate over 1000 watts with reliable final properties.<\/p>\n

In this article, we will discuss how a fibre laser works, where it is used and why it is often the optimal choice when compared to alternatives. But first, let us understand what it is.<\/p>\n

What Is a Fibre Laser?<\/h2>\n

Fibre lasers are a type of solid-state lasers that use optical fibres as their active gain medium. In these lasers, a fibre made of silicate or phosphate glass absorbs raw light from the pump laser diodes and transforms it into a laser beam with a specific wavelength.<\/p>\n

To achieve this, the optical fibre is doped. Doping refers to the practice of mixing a rare-earth element<\/a> into the fibre. By using different doping elements, laser beams can be created with a wide range of wavelengths.<\/p>\n

Some common doping elements in their increasing order of emitted wavelengths are neodymium (780-1100nm), ytterbium (1000-1100nm), praseodymium (1300nm), erbium (1460-1640nm), thulium (1900-250nm), holmium (2025-2200nm), and dysprosium (2600-3400nm).<\/p>\n

Because of such a wide range of produced wavelengths, fibre lasers are perfect for a variety of applications such as laser cutting<\/a>, texturing, cleaning, engraving, drilling, marking and welding. This also enables fibre lasers to find use in many different sectors such as medicine, defence, telecommunications, automotive, spectroscopy, electrical, manufacturing and transportation.<\/p>\n

How a Fibre Laser Works<\/h2>\n
\"Fiber
Schematic diagram of fibre laser<\/figcaption><\/figure>\n

A fibre laser is named after its active gain medium which is an optical fibre. Any fibre laser machine that produces a well-collimated high-power laser does it in five main stages. These are as follows:<\/p>\n

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    Creation of pump light<\/p>\n<\/li>\n

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    Collection and travel into the optical fibre<\/p>\n<\/li>\n

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    Pump light passes through the optical fibre<\/p>\n<\/li>\n

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    Stimulated emission in the laser cavity<\/p>\n<\/li>\n

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    Amplification of raw laser light into a laser beam<\/p>\n<\/li>\n<\/ul>\n

    Creation of pump light<\/h3>\n

    This is where the energy for the laser beam enters the system. In fibre lasers, we use electricity as the energy source. Diodes known as pump laser diodes convert electrical energy into light energy. In high-quality diodes, the conversion is reliable and efficient and produces light energy only with specific wavelengths.<\/p>\n

    Incidentally, low-quality laser diodes were one of the major obstacles that impeded the progress of laser technology for about 3 decades.<\/p>\n

    In most cases, this pump light or pump beam is produced in parts by multiple laser diodes and is then coupled in the fibre optic cable. For instance, there are 20w laser machines that combine pump light from 11 laser diodes in the fibre optic cable.<\/p>\n

    Collection and travel into the optical fibre<\/h3>\n

    A coupler combines the light from multiple laser diodes into one. This coupler is a part of the optical fibre. It has multiple entry points on one side, each of which connects to a fibre from an individual laser diode.<\/p>\n

    On the other side, there’s a single exit point that connects to the main fibre. Once all the light is collected, it travels to the laser medium or the gain medium.<\/p>\n

    Pump light passes through the optical fibre<\/h3>\n
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