We have optimised the design and fabrication of low-loss type-I femtosecond-laser-written waveguides in PPLN that are single-transverse mode at 780 nm and 1560 nm and mode-matched to single-mode fibres. Spontaneous parametric downconversion (SPDC) has been demonstrated at 1560 nm when pumped with a 780 nm DFB laser and has been characterised with measurement of the second-order cross-correlation g(2) using superconducting nanowire detectors. This novel approach to waveguide fabrication in PPLN offers routes to high levels of integration and high generation rates which is important for many quantum-information applications.

We present a cylindrical rod of single-crystal Nd:YAG fabricated from a bulk crystal using femtosecond laser-induced preferential etching. The rod is pumped at 808 nm, and the laser characteristics at 1064 nm emission and the thermal stability are investigated. The slope efficiency was determined with a maximum optical-to-optical efficiency of 7.9%±0.29% and a FWHM linewidth of 299 ± 63 pm. The etched rod shows parameters consistent with existing Nd:YAG gain crystals. This fabrication technology will find use in composite micro-optical devices where microfluidics, active and passive optics, and structures can be etched out of many different materials and combined into a single device.

Using the ultrafast laser inscription technique. buried channel waveguides have been fabricated in gallium lanthanum sulfide and gallium lanthanum sulfide selenide glasses to demonstrate the suitability of the materials for supercontinuum generation in the mid-IR. Supercontinuum generation was performed using 100 femtosecond pump pulses with micro-Joule pulse energies and a center wavelength of 4.6 mu m, which is in the anomalous dispersion regime for these waveguides. Under such pump conditions. supercontinuum was obtained covering a 25-dB-bandwidth of up to 6.1 um with a long-wavelength edge of 8 mu m. To our knowledge, this represents the broadest and the longest-wavelength IR supercontinuum generated from an ultrafast laser inscribed waveguide to date. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.

Ultrafast laser inscription has been used to produce channel waveguides in Ge 22 As 20 Se 58 glass (GASIR-1, Umicore N.V).The mode field diameter and waveguide losses at 2.94 μm were measured along with the waveguide dispersion in the 1 to 4.5 μm range, which is used to estimate the zero-dispersion wavelength.Z-scan measurements of bulk samples have also been performed to determine the nonlinear refractive index.Finally, mid-IR supercontinuum generation has been shown when pumping the waveguides with femtosecond pulses centered at 4.6 μm.Supercontinuum spanning approximately 4 μm from 2.5 to 6.5 μm was measured which, to the best of the authors' knowledge, represents the broadest and the deepest IR supercontinuum from an ultrafast laser inscribed waveguide to date.This work, combined with the long wavelength transmission of GASIR-1 up to 15 μm, paves the way for realizing further ultrafast laser inscribed waveguide devices in GASIR-1 for mid-IR integrated optics applications.

In this talk, we describe our recent work on selenium modified Ga:La:S glasses. The addition of Se improves the infrared transmission sufficiently to capture enough of the 8-12 micron window to allow thermal imaging, while at the same time, allowing sufficient visible transmission for object recognition using conventional image capturing. The addition of Se has other implications, increasing the optical nonlinearity, providing longer fluorescent lifetimes when doped with rare earth ions and expanding the transmission window in the important 3-5 micron region. Ga:La:S glasses are superior to commercially available chalcogenides based on alloys of Ga and/or As with S, Se and/or Te. They offer significantly higher alkaline resistance, greater mechanical strength and over 300oC higher working temperature (Tg > 500oC). All of these new features suggest Ga:La:S-Se may be a material suitable for the next generation of mid-IR sources through supercontinuum or rare earth doping.

Supercontinuum from 2.5 to 6.5 μm has been generated in ULI waveguides pumped with femtosecond pulses centered at 4.6 μm. Dispersion measurements show the zero dispersion wavelength for the waveguides to be around 5.3 μm.

The ultrafast laser inscription technique has been used to fabricate channel waveguides in Tm3+-doped Lu2O3 ceramic gain medium for the first time to our knowledge. Laser operation has been demonstrated using a monolithic microchip cavity with a continuous-wave Ti:sapphire pump source at 796 nm. The maximum output power achieved from the Tm:Lu2O3 waveguide laser was 81 mW at 1942 nm. A maximum slope efficiency of 9.5% was measured with the laser thresholds observed to be in the range of 50-200 mW of absorbed pump power. Propagation losses for this waveguide structure are calculated to be 0.7 dB⋅cm-1 ± 0.3 dB⋅cm-1 at the lasing wavelength.

The ultrafast laser inscription technique has been used to fabricate channel waveguides in Tm 3+ -doped Lu2O3 ceramic gain medium for the first time to our knowledge.Laser operation has been demonstrated using a monolithic microchip cavity with a continuous-wave Ti:sapphire pump source at 796 nm.The maximum output power achieved from the Tm:Lu2O3 waveguide laser was 81 mW at 1942 nm.A maximum slope efficiency of 9.5% was measured with the laser thresholds observed to be in the range of 50-200 mW of absorbed pump power.Propagation losses for this waveguide structure are calculated to be 0.7 dBcm -1 ±0.3 dBcm -1 at the lasing wavelength.

Summary form only given. Ultrafast laser inscription (ULI) allows the fabrication of compact, highly-efficient and robust laser sources over a broad range of crystalline, ceramic and glass gain media. For instance, subsurface waveguides can be formed by the stress induced refractive index modification effect which takes place between two parallel modified regions referred to as “Type II” guiding [1]. Previously, a family of laser hosts known as sesquioxides, namely Lu 2 O 3 , Sc 2 O 3 and LuScO 3 , have been shown to demonstrate efficient, high-power and tunable laser operation around the 2 μm region in both continuous-wave and pulsed regimes when doped with Tm 3 + [2, 3]. Combining the Tm 3+ -doped sesquioxide material properties with the ULI waveguide laser geometry provides a means to produce compact, low-threshold and efficient laser sources near 2 μm with the potential for high pulse repetition rate ultrafast operation. Here we report, to the best of our knowledge, the first demonstration of a ceramic Tm:Lu 2 O 3 waveguide laser source fabricated by ULI.

Ultrafast Laser Inscription (ULI) of waveguides and Z-scan measurements have been performed in Ge 22 As 20 Se 58 glass (GASIR-1). Light guiding at 2.45 μm and 2.9 μm is shown, demonstrating the potential of GASIR-1 for Mid-IR integrated optics.