We demonstrate a method for rapid prototyping of optical fibers. Silica-based glass rods were 3D printed using laser powder deposition. Different doping of the 3D printed rods is evaluated, including alumina, titania, and erbium-doped glass. The rods were subsequently used as the core material in preforms with optical fibers drawn using a laser-based draw tower. A transmission loss of 3.2 dB/m was found for a fiber with 1 wt% titania doped core and pure silica cladding. Using this fabrication method, prototyping from powder to optical fiber could be achieved within a few hours.

Light Detection and Ranging (LIDAR) is a powerful imaging technique. By utilising a superconducting nanowire single photon detector (SNSPD) we construct a 3D scanning LIDAR system operating with eye-safe infrared laser pulses and millimeter precision.

Ultrafast lasers have proven to be a great asset in many fields such as biological imaging [1], high-precision machining [2] and nonlinear spectroscopy [3]. This has resulted in a great interest in the further development of passive mode-locked sources. The most common passive mode-locking techniques today rely on semiconductor saturable absorbers (SESAM) [4] or other artificial saturable absorbers, such as Kerr lensing [5]. While these methods are well established, they still have issues with the durability of the SESAM or the need to reach sufficient intensities for reliable operation of the Kerr lens mechanism.In this work we present a new mechanism for passively mode-locking solid-state lasers using intra-cavity sumfrequency mixing (SFM). The underlying idea is to have two laser cavities with a shared section in which a nonlinear crystal is placed. The nonlinear medium phase-matches the SFM between the two operating wavelengths. By matching the roundtrip time of the two cavities, the same temporal part of the light in the two cavities will always interact. This forces one of the lasers to form a dark pulse and the other a bright pulse. Advantages of this approach is that it works for high repetition rates, can be used for any wavelengths in the transparency window for the nonlinear material and is easy to setup. Moreover, the phase-mismatched frequency doubling in the same crystal might infer cascaded F (2) :F (2) Kerr mechanism which could lead to spectral broadening and solitary mode-locking regime.The setup is shown in Fig. 1, where two Nd:YVO4 lasers resonate in a folded y-cavity, one operating at 1064 nm and the other at 1342 nm. In the shared section of the cavity a periodically poled nonlinear RKTP crystal is placed which is quasi-phase matched (QPM) for SFM between the two lasing wavelengths.

A new technique for mode-locking through sum-frequency generation is presented. The technique produced 200 ps long 1064 nm pulses in a coupled-cavity system with two Nd:YVO4 crystals and a PPRKTP phase-matched for sum-frequency generation.

A new technique for mode-locking is demonstrated based on two lasers sharing one leg for sum-frequency generation. When the two lasers had equal round trip time one will produce bright pulses and the other dark pulses. Both lasers used Nd:YVO4 as the gain material, but operated at different wavelengths, namely 1064 nm and 1342 nm. In the present configuration, sub-250 ps pulses were generated at a repetition rate of 276 MHz with an output power of 70 mW. With appropriate choice of round trip loss at the two wavelengths it was possible to choose which laser was generating the bright pulses.