What Is Fiber Laser? Definition, Features, Principles, Types, and More

What Is Fiber Laser?

Fiber laser is a solid-state laser that uses rare earth element-doped glass fiber as the gain medium, which features with high photoelectric conversion efficiency, simple structure, and good beam quality. It has become the mainstream flow of laser technology development and industrial application. Due to the small footprint of optical fiber, it can be used in a wide range of occasions, and has a high usage rate in the downstream manufacturing and processing field. Fiber lasers have high processing adaptability and can be used in any applications. In addition, the beam quality is better, which can maximize the effect of cost reduction and efficiency improvement for manufacturing enterprises.

Fiber Laser Features

• The corresponding high-power, low-brightness LD light source in the absorption spectrum of rare earth elements can be pumped through the double-clad fiber structure to output high-brightness single-mode laser.
• Small and flexible design, high conversion efficiency, and work under harsh conditions with good cooling system.
• Produced beams with good quality, high conversion efficiency and low threshold.
• The laser output in the 0.38-4um band can be realized by using different rare earth elements, the wavelength selection is easy and tunable, and the tuning range is wide.
• High degree of matching with existing optical communication systems and good coupling.
• Low cost with fiber optic devices and optical fibers, which can greatly reduce the structural cost.

Composition & Principle

Like other types of lasers, a fiber laser consists of three parts: a gain medium, a pump source, and a resonant cavity. It uses active fibers doped with rare earth elements in the core as the gain medium. Generally, a semiconductor laser is used as the pump source. The resonant cavity is generally composed of mirrors, fiber end faces, fiber loop mirrors or fiber gratings. The specific working process is as follows: In the working state, the active fiber (gain fiber) absorbs the energy provided by the pump source, amplifies the output laser after being amplified by the resonant cavity composed of the active fiber and fiber grating.

Seed Source

Also known as the signal source, it is the object of radiation amplification in the laser amplification system. The laser that provides a low-power signal is used as a “seed” to allow the amplification system to amplify according to the state of this “seed”.

Active Optical Fiber

The active fiber is used as a gain medium, and its function is to realize the energy conversion from pump light to signal light to achieve amplification.

Passive Optical Fiber

Passive optical fiber mainly realizes the function of light transmission and does not participate in wavelength conversion. In fiber laser systems, there are mainly fiber gratings, passive matching fibers in fiber isolators, and passive multimode large-core energy transmission fibers in laser energy transmission components. At present, the passive optical fiber products of domestic suppliers can basically meet the production needs, and only a small amount of passive optical fiber used for ultra-high power products still needs to use imported optical fiber.

Fiber Laser Optics

Pump Source

It can be used as a direct light source for industrial semiconductor lasers to output laser light, and can also be used as a pump light source to provide high-power, high-brightness pump light for fiber lasers.

Pump Combiner

The lasers of multiple pump sources can be coupled into the optical fiber to achieve higher power pump laser output.

Energy Combiner

It can superimpose the energy of multiple high-power fiber laser modules, and is the core device to realize multi-mode laser beam combining output.

Fiber Grating

A diffraction grating formed by axially periodically modulating the refractive index of the fiber core through a certain method. It belongs to a passive filter device and is also a necessary component of a resonator. It determines the output wavelength and bandwidth of the laser, and can control the laser mode and beam quality.

Laser Head

It is an important component that can realize long-distance flexible output of high-power laser in the application site, and is compatible with the machining system, so that the laser generated by the laser is transmitted to the processing material to complete the laser machining application.

Isolator

It can effectively protect the laser and effectively prevent the return light from damaging other optical components.

Stripper

It can effectively strip the cladding light in the laser, protect related devices, and improve the quality of the output laser beam. The acousto-optic modulator is mainly used inside the resonator, and modulates the required laser pulse through radio frequency drive modulation technology. It is a Q-switched pulse fiber laser core components.

Pattern Matcher

The core device used to connect two different types of optical fibers can minimize the connection loss of different types of optical fibers and optimize the matching of the laser mode mode field.

Types & Uses

Based on the working mode, there are two most common used types of fiber lasers: continuous laser and pulsed laser. It can be used in cutting, welding, engraving, marking, cleaning and other scenarios.

Continuous Laser

The continuous laser emits light beam continuously, with a peak power of 120KW. It is used in cutting, welding, brazing, drilling. Semi-continuous laser (QCW) is still pulsed in essence, but with a longer pulse width and a peak power of 23KW, which is used in cutting, arc welding, drilling, brazing, metal quenching (improving metal ductility, reducing DC resistance), especially suitable for replacing lamp-pumped YAG lasers in spot welding, seam welding and drilling applications. There is a certain overlap with the continuous laser in use.

Pulsed Laser

Pulsed lasers can be divided into nanosecond, picosecond, femtosecond pulsed lasers. Nanosecond laser (longer pulse width) has a peak power of 1MW in scribing, etching, drilling, surface treatment, quenching, marking. Nanosecond laser (shorter pulse width for micro-finishing) is used for quenching, silicon wafer and glass cutting. Picosecond laser (pulse width reaches picosecond level) has a peak power greater than 10MW, which is used for blackening, sapphire and glass cutting, photovoltaic and OLED cutting. Femtosecond laser (pulse width up to femtosecond level) has a peak power greater than 29MW, which is used for sheet metal cutting, drilling, high-precision processing, and ophthalmic surgery.

Fiber Laser Costs

Fiber Laser Engraver

A fiber laser engraving & making machine is priced from $3,500 to $28,500 based on the pulsed laser powers of 20W, 30W, 50W, 60W, 70W, and 100W.

Fiber Laser Cutter

A fiber laser cutting machine costs from $14,200 to $260,000 based on the continuous laser powers of 1000W, 1500W, 2000W, 3000W, 4000W, 6000W, 8000W, 10000W, 12000W, 15000W, 20000W, 30000W, and up to 40000W.

Fiber Laser Welder

A fiber laser welding machine has a price range from $5,400 to $58,000 based on different types including portable (handheld laser welding gun) welder, automatic (CNC controller) welder, robot welder with continuous laser powers of 1000W, 1500W, 2000W, and 3000W.

Fiber Laser Cleaner

The average price paid for a new fiber laser cleaning machine is from $5,000 to $19,500 based on the pulsed laser powers of 50W, 100W, 200W, 300W, and continuous laser powers of 1000W, 1500W, 2000W, 3000W.