Microstructured waveguides in z-cut LiNbO3 by high-repetition rate direct femtosecond laser inscription

We report on the operational parameters that are required to fabricate buried, microstructured waveguides in a z-cut lithium niobate crystal by the method of direct femtosecond laser inscription using a highrepetition-rate, chirped-pulse oscillator system. Refractive index contrasts as high as −0.0127 have been achieved for individual modification tracks. The results pave the way for developing microstructured WGs with low-loss operation across a wide spectral range, extending into the mid-infrared region up to the end of the transparency range of the host material.

Optimisation of microstructured waveguides in z-cut LiNbO3 crystals

We present a practical approach to the numerical optimisation of the guiding properties of buried microstructured waveguides, which can be fabricated in a z-cut lithium niobate (LiNbO3) crystal by the method of direct femtosecond laser inscription. We demonstrate the possibility to extend the spectral range of low-loss operation of the waveguide into the mid-infrared region beyond 3um.

Optimisation of micro-structured waveguides in lithium niobate (z-cut)

We present an optimization procedure to improve the propagation properties of the depressed cladding, buried micro-structured waveguides formed in a z-cut lithium niobate (LN) crystal by high repetition rate femtosecond (fs) laser writing. It is shown that the propagation wavelength for which the confinement losses of ordinary (O) and extraordinary ordinary (E) polarizations are below 1 dB/cm can be optimized beyond 3 micro meter for hexagonal WG structures with seven rings of tracks.