What are the primary characteristics of a fiber laser?

Fiber lasers are recognized for their high beam quality and excellent efficiency, making option A the correct choice. The fundamental nature of fiber lasers, which utilize glass fibers as the gain medium, allows them to produce a very focused and high-quality beam of light. This high beam quality is crucial for precision applications, such as cutting, welding, and marking, where an accurate focus can greatly enhance performance and outcomes.

Additionally, fiber lasers exhibit excellent efficiency, which is indicative of their ability to convert electrical energy into laser light with minimal waste. This efficiency not only reduces operational costs over time but also enhances the overall performance of laser systems, as less energy is required to achieve the same output compared to other laser types.

In contrast, the other options describe features that are not characteristic of fiber lasers. For instance, B mentions large size and low power delivery, which is inaccurate as fiber lasers are typically compact and can provide high power outputs. C describes low beam quality and poor efficiency, both of which contradict the established advantages of fiber lasers. Lastly, D states high operation costs and minimal power delivery, which again misrepresents the operational profile of fiber lasers, known for their cost-effectiveness and robust power delivery capabilities.