Should Semiconductor Lasers Operate in Continuous or Pulsed Mode?

Should Semiconductor Lasers Operate in Continuous or Pulsed Mode?

Semiconductor lasers can operate in either continuous or pulsed mode, with the choice primarily determined by their operational configuration and application requirements.

Schematic Diagram of Basic Laser Structure

Continuous Wave Laser Diode (CWLD)
Continuous wave semiconductor lasers provide stable, long-duration laser output with consistent power. Common wavelengths for CWLDs include 808nm, 976nm, 1310nm, 1450nm, and 1625nm. In domestic (China-made) continuous-wave semiconductor lasers, single-emitter devices can achieve up to 5W output power, while stacked arrays can reach 100W.

Pulsed Semiconductor Lasers
Pulsed semiconductor lasers emit light in intermittent bursts, typically featuring high peak power but lower average power. Common wavelengths for pulsed lasers include 905nm and 1550nm, with peak power generally reaching several tens of watts.

Application Scenarios of Continuous Wave Semiconductor Lasers:

1. Fiber Optic Communications
   As critical components in optical communication systems, CW laser diodes are used in fiber optic and optical waveguide communications. They generate stable optical signals for data transmission and serve as laser sources in optical networks.

2. Laser Printing and Scanning
   CW laser diodes enable high-resolution imaging in laser printers, scanners, and optical image processing equipment for document and graphic production.

3. Medical Applications
        In medical devices, these lasers are utilized for:

• Laser surgeries

• Ophthalmologic procedures (e.g., LASIK refractive surgery)

• Biomedical imaging and diagnostic laser scanners

4. Material  Processing
        Widely employed for precision material processing including:

• Metal/plastic/ceramic cutting and welding

• Micro-drilling and engraving

5. LiDAR and Optical Sensors
        Key components in:

• Autonomous vehicle LiDAR systems

• Distance/speed measurement sensors

• Environmental perception systems

6. Scientific  Research
        Essential for advanced research applications:

• Atomic physics experiments

• Molecular spectroscopy

• Optical atomic clocks

Application Scenarios of Pulsed Semiconductor Lasers:

1. LiDAR and Optical Sensing
        Pulsed semiconductor lasers are critical in:

• Autonomous vehicle LiDAR systems

• Distance/speed measurement sensors

• Environmental perception systems
  Their high-peak-power pulsed output enables rapid, precise target       detection – ideal for time-of-flight measurement applications.

2. Advanced Material Processing
        Widely used for precision machining:

• Micro-cutting and pulsed laser welding

• Precision drilling and surface engraving
   Pulse energy and width control allows:

• μm-level processing accuracy

• Minimal heat-affected zones

• Enhanced processing efficiency

3. Scientific Research
        Essential for cutting-edge experiments:

• Ultrafast atomic physics studies

• Time-resolved molecular spectroscopy

• Optical frequency standard research
  The ns/ps-level short pulses enable:

• Precise excitation of quantum states

• High-temporal-resolution detection

4. Machine Vision Systems
        Key components for industrial automation:

• High-speed quality inspection

• 3D object recognition and positioning
  Pulsed illumination provides:

• Sub-mm depth resolution

• Reflection-resistant operation

• Real-time 3D profiling capability

Illustration of Songsheng Optoelectronics 976nm Water/Air-Cooled Constant-Temperature Direct Diode Laser

Songsheng Optoelectronics has independently developed a 976nm constant-temperature continuous direct diode laser specifically designed for laser soldering and plastic welding applications. The system features a high-speed PID algorithm with 15μs response time to prevent solder joint burning, and incorporates a built-in closed-loop temperature feedback system. Using infrared sensors, it continuously monitors and precisely regulates the heating point temperature to maintain a stable preset welding temperature. The laser is available in both air-cooled and water-cooled configurations, with output power options ranging from 10W to 1000W (including 10W, 45W, 100W, 200W, 300W, 500W, and 1000W).

In summary, pulsed semiconductor lasers find extensive applications across information technology, medical technology, LiDAR systems, material processing, scientific research, and machine vision. With continuous technological advancements and expanding application fields, their prospects for future applications are becoming increasingly broad.