Pulse Generation and Shaping
The Connet pulse fiber laser and amplifier technology platform includes pulse generation and shaping technologies. According to different application requirements, semiconductor lasers or single-frequency fiber lasers are used to generate picosecond to nanosecond optical pulses. Pulse generation technologies include direct circuit modulation drive, passive mode-locked fiber lasers, and external modulators. Optical pulse shaping technology can help fiber amplifiers achieve higher single pulse energy output, reduce pulse distortion, reduce pulse peak power, increase the threshold of nonlinear effects during fiber amplification, and achieve high power output.
Pulse Generation Technology
● Direct Circuit Modulation Technology
Direct circuit modulation can achieve 0.5ns-1000ns optical pulse output, which is usually used to drive semiconductor lasers such as DFB, and cascaded fiber amplifiers are used to increase the output power level. Connet provides CoLID series pulsed fiber lasers for LiDAR.
● Passive Mode-locking Technology
Passive mode-locking technology is used to achieve ultrafast light pulses on the order of ps and sub-picoseconds.
● External Modulation Technology (AOM/EOM)
Connet uses the external modulation technology of acousto-optic modulator (AOM) and electro-optic modulator (EOM) for high-quality optical pulse generation. The seed laser generally uses CoSF-D or CoSF-R single-frequency fiber laser. This technology does not affect the single-frequency performance of the seed laser. The AOM is used to generate extinction ratio optical pulses of hundreds of nanoseconds. Cascaded single frequency polarization-maintaining pulse fiber amplifiers are used to achieve single pulse energy in the order of hundreds of uJ, up to 1kW peak power diffraction-limited optical pulse output, such single frequency polarization maintaining long pulse fiber laser is widely used in coherent Doppler LiDAR for wind sensing.
Pulse Shaping Technology
In the process of high power pulse fiber amplification, pulse shaping technology is very important. Proper pulse shaping can help reduce the peak power of optical pulses, thereby increasing the threshold of fiber nonlinear effects, such as stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), self-phase modulation (SPM), cross-phase modulation (XPM), four-wave mixing (FWM), etc.