Introduce fiber pulsed lasers
Fiber Pulsed lasers are laser devices that use fibers doped with rare earth ions (such as ytterbium, erbium, thulium, etc.) as the gain medium. They consist of a gain medium, an optical resonant cavity, and a pump source. Its pulse generation technology mainly includes Q-switching technology (nanosecond level), active mode-locking (picosecond level), passive mode-locking (femtosecond level), and main oscillation power amplification (MOPA) technology.
Industrial applications cover metal cutting, welding, laser cleaning and lithium battery TAB cutting in the new energy field, with multi-mode output power reaching the ten-thousand-watt level. In the field of lidar, 1550nm pulsed lasers, with their high pulse energy and eye-safe features, are applied in ranging and vehicle-mounted radar systems.
The main product types include Q-switched type, MOPA type and high-power fiber pulsed lasers. Category:
1. Q-switched fiber laser: The principle of Q-switching is to add a loss-adjustable device inside the laser. In most time periods, the laser has a large loss and almost no light output. Within an extremely short period of time, reducing the loss of the device enables the laser to output a very intense short pulse. Q-switched fiber lasers can be achieved either actively or passively. Active technology typically involves adding an intensity modulator inside the cavity to control the loss of the laser. Passive techniques utilize saturated absorbers or other nonlinear effects such as stimulated Raman scattering and stimulated Brillouin scattering to form Q-modulation mechanisms. The pulses generally generated by Q-switching methods are at the nanosecond level. If shorter pulses are to be generated, it can be achieved through the mode-locking method.
2. Mode-locked fiber laser: It can generate ultrashort pulses through active mode-locking or passive mode-locking methods. Due to the response time of the modulator, the pulse width generated by active mode-locking is generally at the picosecond level. Passive mode-locking utilizes passive mode-locking devices, which have a very short response time and can generate pulses on the femtosecond scale.
Here is a brief introduction to the principle of mold locking.
There are countless longitudinal modes in a laser resonant cavity. For a ring-shaped cavity, the frequency interval of the longitudinal modes is equal to /CCL, where C is the speed of light and CL is the optical path length of the signal light traveling one round trip within the cavity. Generally speaking, the gain bandwidth of fiber lasers is relatively large, and a large number of longitudinal modes operate simultaneously. The total number of modes that the laser can accommodate depends on the longitudinal mode interval ∆ν and the gain bandwidth of the gain medium. The smaller the longitudinal mode interval, the greater the gain bandwidth of the medium, and the more longitudinal modes can be supported. Conversely, the less.
3. Quasi-continuous laser (QCW laser) : It is a special working mode between continuous wave lasers (CW) and pulsed lasers. It achieves high instantaneous power output through periodic long pulses (duty cycle typically ≤1%) while maintaining a relatively low average power. It combines the stability of continuous lasers with the peak power advantage of pulsed lasers.
Technical principle: QCW lasers load modulation modules in the continuous laser circuit to cut continuous lasers into high duty cycle pulse sequences, achieving flexible switching between continuous and pulse modes. Its core feature is the “short-term burst, long-term cooling” mechanism. The cooling in the pulse gap reduces heat accumulation and lowers the risk of material thermal deformation.
Advantages and features: Dual-mode integration: It combines the peak power of pulse mode (up to 10 times the average power of continuous mode) with the high efficiency and stability of continuous mode.
Low energy consumption: High electro-optical conversion efficiency and low long-term usage cost.
Beam quality: The high beam quality of fiber lasers supports precise micro-machining.
Post time: Nov-10-2025