Iterative phase retrieval has been used to reconstruct the near-field distribution behind tailored X-ray waveguide arrays, by inversion of the measured far-field pattern recorded under fully coherent conditions. It is thereby shown that multi-waveguide interference can be exploited to control the near-field distribution behind the waveguide exit. This can, for example, serve to create a seconda...

A novel scheme is presented that can be used to efficiently pump optical waveguide amplifiers. It is based on the coupling between two adjacent waveguides, where pump light is gradually coupled from a nonabsorbing pump waveguide into the amplifier waveguide. The coupling between the waveguides in such a configuration is calculated using an improved coupled mode theory (CMT). The proposed distri...

Planar waveguides made of Nd 3+ -doped silicon rich silicon oxide (SRSO) and silicon rich silicon nitride (SRSN) have been fabricated by reactive magnetron sputtering and characterized with special emphasis on the comparison of the guided photoluminescence (PL) properties of these two matrices. Guided fluorescence excited by top surface pumping at 488 nm on planar waveguides was measured as a f...

Introduction: Er3+:Yb3+ codoping has become an effective method for producing short, efficient lasers and amplifiers in the long haul telecommunications wavelength range. Ytterbium codoping increases the pump absorption near 980nm and efficient energy transfer between the Yb’’ and the Er3+ ions enables the operation of centimetre long lasers with low Er” concentrations. This mechanism was first...