In today's era of rapid development of laser technology, solid-state lasers and fiber lasers, as the two major mainstream laser products, have each demonstrated their unique charm and advantages in many fields such as industrial production, scientific research, and military applications.
1. Technical principles and performance differences
1.1 Gain medium
Fiber lasers use rare earth-doped glass fibers as gain media. Under the action of pump light, high power density is formed in the fiber, resulting in a population inversion of the laser energy level and laser oscillation through the positive feedback loop of the resonant cavity. Fiber lasers are compact and do not require a complex cooling system, and the flexibility of the fiber makes them more advantageous in multi-dimensional space processing applications. The core of a fiber laser is an optical fiber, a flexible, hair-thin glass or plastic filament known for its ability to guide light over long distances with minimal loss. The fiber acts as the active gain medium of the laser and is the core of the laser's operation. However, unlike the undoped glass or plastic fibers used in telecommunications, the optical fiber in a fiber laser is doped with rare earth elements such as erbium or ytterbium. This doping introduces the energy state required for laser operation, allowing the fiber to not only guide light but also amplify it. Solid-State Laser (SSL) is centered on its unique gain medium, solid material, and is usually composed of four parts: gain medium, cooling system, optical resonant cavity, and pump source. The gain medium, such as ruby (Cr:Al₂O₃) or neodymium-doped yttrium aluminum garnet (Nd:YAG), is the soul of the solid-state laser. The activated ions (such as Nd³⁺) doped inside it achieve population inversion under the action of pump light, thereby generating laser light. The cooling system is responsible for removing the heat accumulated inside the gain medium due to laser generation to ensure stable operation of the laser. The optical resonator forms continuous oscillations through positive feedback of photons, outputting a highly monochromatic and highly directional laser beam.
1.2 Performance and efficiency Fiber lasers are known for their excellent electrical efficiency, thanks to the nature of fiber optic cables, which can conduct light with minimal loss. This feature makes fiber lasers incredibly energy efficient, often achieving efficiencies of more than 30%. Solid-state lasers are generally less efficient, probably due to the higher losses of their larger gain media and the need for high-intensity lamps for pumping.
1.3 Beam quality: directly affects the effectiveness of lasers in precision applications Single-mode operation of fiber lasers can provide incredibly high beam quality, characterized by tight focusing and minimal divergence. Solid-state lasers, while capable of providing high-quality beams, are often difficult to match the beam quality of fiber lasers, especially at higher power levels. Despite their lower efficiency and beam quality, solid-state lasers are not without their advantages. They have powerful power scaling capabilities and are well suited for high-power applications. Solid-state lasers can be designed to produce incredibly high power levels by increasing the size of the gain medium and the pump power, which is not so simple for fiber lasers due to the limitations of fiber size and heat dissipation.
1.4 Stability Fiber lasers have high stability. Their fiber structure is insensitive to environmental changes (such as temperature, humidity, vibration, etc.) and can maintain stable working conditions in harsh environments. At the same time, fiber lasers are considered more durable and adaptable to environmental changes because they use a solid-state structure and do not contain free-space optical components. Solid-state lasers have relatively poor stability, and changes in environmental factors may have a greater impact on their performance.
1.5 Heat dissipation Fiber lasers have excellent heat dissipation performance. Its gain medium is optical fiber, which has a large surface area to volume ratio, and heat can be dissipated quickly, so it can work stably for a long time and can withstand high power output. Solid-state lasers are relatively difficult to dissipate heat, and are prone to thermal effects when operating at high power, affecting the performance and life of the laser.
1.6 Size and maintenance costs Fiber lasers are very compact and require almost no maintenance. The small size of the fiber and the absence of external mirrors greatly reduce the alignment problems associated with solid-state lasers. In addition, the excellent heat dissipation capabilities of the fiber usually do not require active cooling, further reducing maintenance requirements. At the same time, fiber lasers are generally safer to operate because the laser is confined within the fiber, reducing the risk of accidental exposure. The alignment of mirrors in solid-state lasers is critical to their operation and requires regular inspection and adjustment, which increases the maintenance workload. In addition, solid-state lasers usually require active cooling to manage the heat generated in the gain medium, which not only increases the complexity of the system, but also increases maintenance requirements. Solid-state lasers tend to be larger than fiber lasers. The need for large gain mirrors and external mirrors increases their size and weight, limiting their applicability in applications with limited space.
2. Application fields
Fiber lasers shine in the field of industrial cutting and welding with their high power, high beam quality, good heat dissipation performance and stability. Fiber lasers are particularly suitable for thick plate cutting and welding of metal materials. Their high electro-optical conversion efficiency and adjustment-free and maintenance-free design greatly reduce the cost of use and the difficulty of maintenance. At the same time, the high tolerance of fiber lasers to harsh working environments, such as dust, vibration, humidity, etc., also makes them perform well in various industrial sites. Continuous lasers have a high degree of penetration in the field of macro processing, and have gradually replaced traditional processing methods in this field. Solid-state lasers are unique in the field of ultra-precision and ultra-micro processing with their high peak power, large pulse energy and short-wavelength laser output (such as green light and ultraviolet light). In processes such as metal/non-metal material marking, cutting, drilling and welding, solid-state lasers can achieve higher processing accuracy and wider material applicability. Especially in high-precision welding and light-curing 3D printing of non-metallic materials, solid-state lasers have become the preferred equipment due to their short-wavelength lasers with small thermal effects and high processing accuracy. Solid-state lasers are mainly used in the field of precision micro-machining of non-metallic materials and thin, brittle and other metal materials due to their short wavelength (ultraviolet, deep ultraviolet), short pulse width (picosecond, femtosecond) and high peak power. In addition, solid-state lasers are widely used in cutting-edge scientific research in the fields of environment, medicine, military and so on.
3. Market share my country is in the process of transformation and upgrading of manufacturing industry from low-end manufacturing to high-end manufacturing. Low-end manufacturing accounts for a high proportion. The macro-processing market covers both low-end manufacturing and some high-end manufacturing. The market demand is large. Therefore, the market capacity of fiber lasers is relatively large. The domestic low-power fiber lasers are highly localized, and there are many large-scale domestic manufacturers. According to the "China Laser Industry Development Report", low-power fiber lasers have been fully replaced by domestic products; in terms of medium-power continuous fiber lasers, domestic quality has no obvious disadvantages, the price advantage is obvious, and the market share is comparable; in terms of high-power continuous fiber lasers, domestic brands have achieved partial sales. As for solid-state lasers, due to the late development in China, there are currently no listed companies with this product as their main business, and they generally purchase foreign brands. Fiber lasers are mainly used in the field of macro processing due to their high output power (laser macro processing generally refers to the processing of the size and shape of the processing object with the influence of the laser beam on the millimeter level); solid lasers are widely used in the field of micro processing due to their advantages such as short wavelength, narrow pulse width, and high peak power (micro processing generally refers to the processing of size and shape with precision reaching micrometers or even nanometers), resulting in certain differences between users of solid lasers and fiber lasers. In general, solid lasers and fiber lasers have different focuses in their application fields and each has its own application field. There is no direct competition between the two in most fields. In the field of metal material processing that overlaps with the field of micro processing, when the metal reaches a certain thickness, this field generally adopts traditional methods or fiber lasers due to cost reasons. Solid lasers are only used in scenes where the metal thickness is thin or the processing requirements are high and the cost is not sensitive. In addition, the competition overlap between the two is low. Solid lasers are mainly used for the processing of non-metallic materials (glass, ceramics, plastics, polymers, packaging, other brittle materials, etc.), and in the field of metal materials, they are used in scenes with high precision requirements and relatively insensitive to cost.