We demonstrate an all-normal dispersion passively mode-locked Yb-doped fiber laser for the supercontinuum (SC) generation based on the nonlinear polarization rotation technique. A piece of polarization-maintaining fiber is utilized in the cavity as a spectral filter. By changing the pump power as well as the polarization states, pulses at repetition rates of 22.85, 45.7, 91.40 MHz can be achieved, corresponding to the fundamental and the second- and the fourth-ordered repetition rates, respectively. The output spectrum has a central wavelength of 1040 nm with steep edges, which indicates that it is a dissipative soliton (DS) mode-locking state. By launching the amplified DS pulses into a piece of photonic crystal fiber at a fundamental repetition rate, SC exhibiting a spectral range from 700 to 1700 nm is realized.
Laser fuze has been widely used in a variety of large-caliber ammunitions, such as missile, aerial bomb and rocket bomb,
due to its typical advantages of proactivity in target detection, sharp directivity of probe field and strong antielectromagnetic
interference ability. Recently a new kind of small laser fuze adapted to small-caliber ammunitions is
being actively developed. Designed the mathematic model of the laser echo waveform based on Gauss beam and
deduced time domain of echo impulse power with varied sharps of target (such as plane target, circle target and mutant
target). Echo impulse waveform of laser fuse with the noise interference, such as sunlight and raindrop, also has been
studied based on the modeling. The test experiments show that the system can detect weak laser echoed wave,
distinguish target and interferences signal by amplifying, modulating and processing the echoed waveform, and detect
vertical test board (gray iron) at 5m far away with no more than 90mA current. The test results in High overload
conditions indicates that the prototyping can work normally and steadily in the whole trajectory.