Reference for selecting single-mode fiber laser

Reference for selecting single-mode fiber laser
In practical applications, choosing a suitable single-mode fiber laser requires a systematic weighing of various parameters to ensure that its performance matches specific application requirements, operating environment and budget constraints. This section will provide a practical selection methodology based on requirements.
Selection strategy based on application scenarios
The performance requirements for lasers vary significantly across different application scenarios. The first step in selection is to clarify the core demands of the application.
Precision material processing and micro-nano manufacturing: Such applications include fine cutting, drilling, semiconductor wafer dicing, micron-level marking and 3D printing, etc. They have extremely high requirements for beam quality and focused spot size. A laser with an M² factor as close as possible to 1 (such as <1.1) should be selected. The output power needs to be determined based on the material thickness and processing speed. Generally, a power ranging from tens to hundreds of watts can meet the requirements of most micro-processing. In terms of wavelength, 1064nm is the preferred choice for most metal material processing due to its high absorption rate and low cost per watt of laser power.
Scientific research and high-end measurement: Application scenarios include optical tweezers, cold atom physics, high-resolution spectroscopy and interferometry. These fields usually have an extreme pursuit of the monochromaticity, frequency stability and noise performance of lasers. Models with narrow linewidth (even single frequency) and low-intensity noise should be given priority. The wavelength should be selected based on the resonance line of a specific atom or molecule (for example, 780nm is commonly used for cooling rubidium atoms). Bias maintenance output is usually necessary for interference experiments. The power requirement is generally not high, and several hundred milliwatts to several watts are often sufficient.
Medical and biotechnology: Applications include ophthalmic surgery, skin treatment and fluorescence microscopy imaging. Eye safety is the primary consideration, so lasers with wavelengths of 1550nm or 2μm, which are in the eye safety band, are often selected. For diagnostic applications, attention needs to be paid to power stability; For therapeutic applications, the appropriate power should be selected based on the depth of treatment and energy requirements. The flexibility of optical transmission is a major advantage in such applications.
Communication and Sensing: Fiber optic sensing, liDAR and space optical communication are typical applications. These scenarios require laser to have high reliability, environmental adaptability and long-term stability. The 1550nm band has become the preferred choice due to its lowest transmission loss in optical fibers. For coherent detection systems (such as coherent lidar), a linearly polarized laser with an extremely narrow linewidth is required as a local oscillator.
2. Priority sorting of key parameters
Faced with numerous parameters, decisions can be made based on the following priorities:
Decisive parameters: First, determine the wavelength and beam quality. The wavelength is determined by the essential requirements of the application (material absorption characteristics, safety standards, atomic resonance lines), and usually there is no room for compromise. The beam quality directly determines the basic feasibility of the application. For instance, precision machining cannot accept lasers with an excessively high M².
Performance parameters: Secondly, pay attention to the output power and line width/polarization. The power must meet the energy threshold or efficiency requirements of the application. The linewidth and polarization characteristics are determined based on the specific technical route of the application (such as whether interference or frequency doubling is involved). Practical parameters: Finally, consider stability (such as long-term output power stability), reliability (fault-free operation time), volume power consumption, interface compatibility and cost. These parameters affect the integration difficulty and total cost of ownership of the laser in the actual working environment.

3. Selection and judgment between single-mode and multi-mode
Although this article focuses on single-mode fiber lasers, it is crucial to clearly understand the necessity of choosing single-mode in actual selection. When the core requirements of an application are the highest processing accuracy, the smallest heat-affected zone, the ultimate focusing capability or the longest transmission distance, a single-mode fiber laser is the only correct choice. Conversely, if the application mainly involves thick plate welding, large-area surface treatment or short-distance high-power transmission, and the absolute accuracy requirement is not high, then multimode fiber lasers may become a more economical and practical choice due to their higher total power and lower cost.