Beam combinable, kilowatt, all-fiber amplifier based on phase-modulated laser gain competition.

We report power scaling results of a highly efficient narrow-linewidth monolithic Yb-doped fiber amplifier seeded with two signals, operating at 1038 and 1064 nm. With the appropriate seed power ratio applied, this technique was shown to suppress stimulated Brillouin scattering in conjunction with phase modulation, while generating the output power in predominantly the longer wavelength signal. Notably, the integration of laser gain competition with pseudo-random bit sequence phase modulation, set at a clock rate of 2.

High-efficiency, kilowatt 1034 nm all-fiber amplifier operating at 11 pm linewidth.

We present power scaling results of a monolithic Yb-doped 1034 nm fiber amplifier well-suited for beam combining applications. Stimulated Brillouin scattering suppression is achieved through optical linewidth broadening, and results were compared for both white noise source (WNS) and pseudo-random bit sequence (PRBS) phase modulation schemes. Notably, through PRBS modulation at a clock rate of 3.

Strong optical injection and the differential gain in a quantum dash laser.

By optically injecting a quantum dash laser and simultaneously producing a significant lowering of the device threshold, a large enhancement in the differential gain is realized. This effect is observed by way of a dramatic reduction in the linewidth enhancement factor and a large increase in the 3-dB modulation bandwidth, especially as the injection wavelength is blue-shifted. Compared to its free-running value, a 50X improvement in the laser's differential gain is found.

Two-color multi-section quantum dot distributed feedback laser.

A dual-wavelength emission source is realized by asymmetrically pumping a two-section quantum-dot distributed feedback laser. It is found that under asymmetric bias conditions, the powers between the ground-state and excited-state modes of the two-section device can be equalized, which is mainly attributed to the unique carrier dynamics of the quantum-dot gain medium. As a result, a two-color emission with an 8-THz frequency difference is realized that has potential as a compact THz source.