Q-switched lasers and MOPA (Master Oscillator Power Amplifier) are special lasers that have some differences in their applications and operating principles. The Q-switched technology of Q-switched lasers is a special technology used to compress the output pulse width of the laser and increase the peak power of the pulse. The MOPA technology of MOPA is the power amplifier for the main oscillator.
Differences between Q-switched Laser and MOPA Laser
Q-switched technology is based on a special key component-the intracavity fast optical switch, generally known as the laser Q-switch, or simply Q-switch.
Schematic Diagram of Q-Switched Laser Technology
1.The working principle of a Q-switched laser:
A fast optical switch (Q-switch) is inserted into the laser resonance cavity, which is in the “off” or “low Q” state during one period of time after the optical pump pulse.
At the same time, the cavity cannot form oscillations and population inversion is constantly increasing; The Q switched of the cavity suddenly switches to the “on” or “high Q” state when the degree of population inversion reaches the maximum. Therefore, it forms an instantaneous strong laser oscillation in the cavity and generates the output of the Q-switched laser pulse to the outside.
2.The characteristics and applications of a Q-switched laser:
The single pulse energy of Q-switched technology is large and can be made into a high-power laser, which is one of the main technologies for high-power lasers. But the adjustable frequency range is small and the pulse width is relatively long. Q- switched laser is capable of generating very short pulses, typically on time scales of nanoseconds (10^-9 seconds) or even short, and delivering very high peak powers. Therefore, it can be used in materials processing, medical aesthetics, radar and telemetry that require high peak power and high energy density, such as laser cutting, engraving and tattoo removal.
MOPA technology to achieve high power amplification of the seed signal, the seed signal and the high beam quality pump light need to be coupled into a double-clad fiber to amplify it in a certain way.
Schematic Diagram of MOPA Laser Technology
1.The working principle of a MOPA Laser:
The main oscillator produces a high-quality starting light with a very good beam quality ranging from high to low output power. The starting light is fed into a single or multi-stage fiber amplifier for amplification, which ensures high beam quality with high output power and energy. It combines the good pulse characteristics of a low power seeding source with the high-power amplification of a double-cladding amplifier.
2.The characteristics and applications of a MOPA Laser:
MOPA technology has good beam quality, short sub-nanosecond pulse widths, a large adjustable frequency range and fast laser response. MOPA is typically used in applications that require longer pulses and higher average power, such as material processing, laser marking, laser printing and communications. Relatively long pulse widths are more suitable for applications requiring material heating or thermal effects.
Comparison of Processing Effects between Q-switched Laser and MOPA Laser
Comparison of Black Marking Effects on Anodized Aluminum
Comparison of Breakdown Effects on Anodized Aluminum Foils
Comparison of Processing Effects on Metal Materials
Comparison of Processing Effects on Plastic Materials
Comparison of Processing Effects on UV Materials
Q-switched laser is an effective method of generating high-energy laser pulses, and the Q value of the laser is adjusted by modulating the loss in the laser cavity. MOPA have longer pulse durations than Q- switched laser, typically between nanoseconds and microseconds (10^-6 seconds). The application range of Q-modulated lasers is high peak powers and energy densities, while MOPA require high average powers and a certain pulse width.