The Nitrogen Content in the Fruiting Body and Mycelium of and Its Utilization as a Medium Component in Thraustochytrid Fermentation.

Following the idea of a circular bioeconomy, the use of side streams as substitutes for cultivation media (components) in bioprocesses would mean an enormous economic and ecological advantage. Costly compounds in conventional media for the production of the triterpene squalene in thraustochytrids are the main carbon source and complex nitrogen sources. Among other side streams examined, extracts from the spent mycelium of the basidiomycete were best-suited to acting as alternative nitrogen sources in cultivation media for thraustochytrids.

Single-mode monolithic fiber laser with 200 W output power at a wavelength of 1018 nm.

We report on an ytterbium-doped monolithic fiber laser at a wavelength of 1018 nm with an output power of 200 W in continuous wave operation. The optimal parameters for setting up such a high-power fiber laser with an ytterbium-doped fiber are investigated and discussed in detail. An in-house-developed pump light stripper and a single-mode fused fiber coupler were applied to use the fiber laser for core-pumping of ytterbium-doped high-power fiber amplifiers in a monolithic setup.

Analysis of the modal evolution in fused-type mode-selective fiber couplers.

Fused-type mode-selective fiber couplers exciting the LP(11) mode are fabricated by well-defined fiber cladding reduction, pretapering and fusion. At a wavelength of 905 nm 80 % of the injected power in the single-mode fiber was transmitted in the few-mode fiber selectively exciting the LP(11) mode. The coupling behavior was experimentally investigated for the case of strong as well as weak fusion.

Matching of the propagation constants in an asymmetric single-mode fused fiber coupler for core pumping thulium-doped fiber at 795 nm.

We developed a fused fiber coupler (FFC) capable of multiplexing wavelengths in the range of 795 nm and 2 μm. A simple 2D simulation model to calculate the pretaper length for matching the propagation constants in the coupling region was established. Based on the numerical data, we fabricated an asymmetric FFC consisting of two different fibers with single-mode guidance for the respective wavelength, achieving a transmission of 90% in the signal fiber for both wavelengths.

Picosecond all-fiber cascaded Raman shifter pumped by an amplified gain switched laser diode.

We investigated an all-fiber picosecond Raman shifter, pumped by an amplified gain switched laser diode in detail. The Raman shifter emitted ps pulses simultaneously at 8 different central wavelengths in the region between 1.06 µm and 1.

0.5 µJ pulses from a giant-chirp ytterbium fiber oscillator.

We present a mode-locked all-normal dispersion ytterbium fiber oscillator with output pulse energies beyond 0.5 µJ. The oscillator is mode-locked using nonlinear polarization rotation, and stable single-pulse operation is achieved by spectral filtering inside the resonator.

50 fs pulses from an all-normal dispersion erbium fiber oscillator.

We present a mode-locked, all-normal-dispersion erbium-doped fiber oscillator generating output pulses with broadband spectra covering the range from 1475 to 1620 nm. The oscillator operates at a repetition rate of 109 MHz with output pulse energies of 1.6 nJ.

High-power dissipative solitons from an all-normal dispersion erbium fiber oscillator.

We demonstrate output pulse energies of 20 nJ from an erbium-doped fiber oscillator that contains only positive dispersion fibers and is mode locked by use of nonlinear polarization evolution and stabilized with a birefringent filter. The fiber oscillator operates at a repetition rate of 3.5 MHz with a central wavelength of 1550 nm.