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Abstract: Following various works on second harmonic process using periodically poled Lithium Niobate crystals (PPLN), we report on the performances comparison between commercial bulk and proton-exchanged waveguide crystals operating at 1029nm. We use a continuous wave (CW) amplified Yb doped single fiber laser delivering up to 500mW in single mode regime. In case of bulk crystal we generate 4mW using 400mW IR power. The use of waveguide crystal leads to an increase of the harmonic power up to 33mW with input IR power limited to 200mW. Nevertheless, this impressive efficiency was affected by the long term degradation of the non-linear waveguide crystal. A decrease of about 40% of the conversion efficiency was observed after 2 years of use, neither associated to the degradation of the coupling efficiency nor to that of the AR coating. This behavior could be attributed to a slow diffusion of protons in the guide. [Copyright &y& Elsevier]

The paper reviews our research efforts in femtosecond laser inscription of optical waveguides inside active Er:Yb-doped glass substrates and in the development of compact waveguide lasers. By optimising the fabrication parameters we obtain waveguides with coupling losses to standard telecom fibers as low as 0.1 dB/facet and propagation losses lower than 0.4 dB/cm. The waveguides provide net gain, with a peak value of 7 dB, and laser action in the whole telecommunications C-band (1530–1565 nm). Single-frequency operation with output power up to 50 mW and passive mode-locking are demonstrated, making the systems useful as compact telecom transmitters. Our results show that femtosecond laser writing can produce high-quality photonic devices, with performance comparable to or better than that obtainable with conventional waveguide fabrication techniques. [ABSTRACT FROM AUTHOR]

We demonstrate laser action from a waveguide fabricated in an Er:Yb-doped silicate glass using femtosecond laser inscription. Waveguides were fabricated using a diode-pumped Yb:glass oscillator at a 600-kHz repetition rate. The multiscan technique was used to control the waveguide cross section. Textbook threshold characteristics are observed for both 980 nm and dual-wavelength excitation. [ABSTRACT FROM PUBLISHER]

A low insertion loss waveguide is fabricated in z-cut lithium niobate using femtosecond laser waveguide inscription. To fabricate a waveguide exhibiting both low propagation and coupling losses, we used the multiscan fabrication technique to control the size of the waveguide cross section. A minimum insertion loss of only 3.5 dB at 1550 nm was measured for the 18-mm-long waveguide when directly coupled to Corning SMF-28 fibers. Of this 3.5dB, we attribute 2.1 dB to coupling losses, 1.1 dB to propagation losses, and 0.3 dB to Fresnel reflections [ABSTRACT FROM PUBLISHER]

A report is presented on the fabrication, by a femtosecond stretched-cavity Ti:Sapphire oscillator, of passive photonic devices operating in the telecom range. The waveguides are written in IOG10 (Schott) glass. Characterisation and performances of a 1 × 2, 1 × 4 splitter are presented. [ABSTRACT FROM AUTHOR]