A New Component Toolbox for 2 Micron Fiber Lasers

ISLA
Acousto-optic device manufacture

Gooch & Housego now offers a full suite of passive and active components to enable high power, all-fiber laser systems at 2 µm for use in materials processing, surgery and sensing. Developed over three years during the ISLA project (Integrated disruptive components for 2 µm fiber Lasers), the components draw on G&H core competencies in design and manufacturing of fused fiber components and acousto-optic devices.

Fiber lasers have become a workhorse in material processing, where they are valued for their high power, low maintenance, and the convenience of routing light directly to the sample. Most existing fiber lasers operate at 1 µm, but 2 µm offers unique wavelength advantages and the potential for 10x the power output due to the increased fiber core size. However, incompatibilities between components and gaps in the component toolbox have inhibited the development of all-fiber 2 µm systems.

G&H has created several new lines of low-loss fused fiber couplers for use at 2 µm, adapting existing processes to accommodate the increased fiber bend radius and water absorption seen in fiber and adhesives at 2 µm. Single-mode and polarization-maintaining splitters and taps are now available, as well as 7×1 and Nx1+1 combiners for high power. WDM couplers for 790, 1210, and 1550 nm enable pumping of both double-clad and single-clad 2 µm fiber.

Wavelength-flattening is an important part of several components’ design to allow laser tuning over a 400 nm range for spectroscopy applications. Synergistic with work for swept sources in optical coherence tomography (OCT), other applications of 2 µm components in spectroscopy include pigment analysis in art and remote monitoring of CO2 and water from satellites. In addition to the fused fiber components now available as standard products, G&H also developed fiber-coupled isolators for use at 2 µm to preserve stable laser operation, available on a custom and OEM basis.

On the active components side, G&H offers modulators at 2 µm for laser applications, and acousto-optic tunable filters (AOTFs). Drawing on extensive experience in modulator design, AMTIR was chosen as the material to launch a series of Acousto Optic Modulators; minimizing drive power and polarization dependence, with complementary TeOmodulators to serve a wider range of applications. A silicon-based pulse picker, unique in the industry, has been fabricated for fast rise times and high efficiency. All of the devices described are commercially available on request.

Our ability to grow and process large boules of optical quality TeO2 has enabled the development of large interaction-length AO devices, and especially AOTFs. In particular this has enabled our development of narrow linewidth tunable filters. A second AOTF design based on a null-shift pair is available on a custom basis for applications where the frequency-shift; for example the incremental frequency-shift in a laser cavity, is undesirable.

With this new suite of components for use at 2 µm, G&H demonstrates an ability to pioneer new techniques in fused fiber and acousto-optic component design and to commercialize those products for volume production. Fiber laser developers now have a whole new set of tools to enable applications in industrial processing, communications, medicine, and spectroscopy.

For more information on G&H’s 2 µm fiber components please contact us at sales@goochandhousego.com.