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Laser
Demand for high power fiber lasers has increased tremendously in recent years. They are used in industrial machines, LIDAR systems, very high-energy laser facilities (inertial fusion, plasma), and recently in optical systems that can deliver very high power for defense applications. Compared with chemical lasers, free-electron lasers or solid-state lasers which are expensive and complex to implement, fiber lasers offer many advantages: compactness, lower mass allowing easier deployment, lower production and operating costs, higher reliability over time, resistance to severe environments, etc.
Today, phasing multiple fiber sources of several kilowatts by optical combination can result in laser architectures delivering powers of tens to hundreds of kilowatts. Exail offers particularly adapted optical components for the development of laser architectures delivering high power: LiNbO3 phase modulators (in 1-2 µm), doped fibers (in 2 µm) and Variable Optical Delay Lines (VODL).
Combining laser beams to gain power
Coherent Beam Combination (CBC)
Gaining power with several combined laser beams can be done by superimposing lasers of distinct wavelengths in a uniform laser output. The combination of several lasers by Coherent Beam Combination (CBC) allows a real-time control of their relative phases to permanently maintain constructive interferences and thus guarantee maximum power efficiency during the combination.
Low linewidth and low phase noise seeder laser
Large bandwidth phase modulator
Optical fibers for power amplifiers
Variable Optical Delay Line (VODL)
Low Frequency Phase Modulator
Exail developed dedicated optical components and integrated sub-systems enabling the manufacturing of complete CBC laser structure:
- Large electro-optical bandwidth LiNbO3 phase modulators to broaden the spectrum and avoid the Stimulated Brillouin Scattering (SBS) effect: NIR-MPZ-LN series with low Vπ
- Low frequency LiNbO3 phase modulators per channel to unbalance the fiber length dispersion coming from environmental disturbance: NIR-MPX-LN-0,1
- Doped optical fibers (Yb-doped for 1 µm, Tm/Ho-doped for 2 µm) with large mode area (LMA) for the development of optical power amplifiers (PM or SM) for the booster and the kW class amplifiers
- Variable Optical Delay Line (VODL) based on micro-optical assemblies, to equalize the optical path for each beam.
Exail’s know-how in precise integration of optical components led to the development of the ModBox-CBC, an optimized multi-channels phase modulation solution for multibeam coherent combination. With 4 or 8 parallel and independent channels featuring low-frequency phase modulators, their matching RF electronics, and VODL, it ensures high optical performances and precise phase adjustments.
Learn moreSpectral Beam Combination (SBC)
The construction of a high-power fiber laser by combining different laser beams can also be done with the Spectral Beam Combination (SBC) technique. Different laser beams emitting a continuous signal, centered on distinct wavelengths, are superimposed by adaptive optics. The result of the laser system is a uniform intensity distribution and an optical signal with power proportional to the number of laser beams combined.
However, the maximum transmitted optical power in each fiber amplifier is severely constrained by the non-linear Brillouin effect. This effect, also called Stimulated Brillouin Scattering (SBS) can be mitigated by broadening the laser linewidth (to spread the spectral power density some GHz around the central wavelength) by the means of an electro-optical phase modulator. To create these side bands, three different RF sources can be combined with the electro-optical phase modulator. A sinusoidal electric signal, a “white noise” or a telecom “PRBS – Pseudo- Random-Bit-Sequence”. With this technique, optical output higher than a kilowatt continuous signal can be reached, spectrally modulated, and combined with other fiber amplifiers to obtain the final and expected laser power level.
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Wide Bandwith Phase modulator
Fiber laser chassis
Fiber laser module
Laser seeder
Optical amplification
Delivery fiber
Fiber array
Transform mirror
Laser output
Diffraction grating
An integrated solution for Coherent Beam Combination (CBC)
The Modbox-CBC is an optimized multi-channels phase modulation solution for multibeam coherent combination. Such a turnkey laser seeder embeds multi-beams phase modulators arrays, and Variable Optical Delay Line in option. This integrated solution ensures high optical performances thanks to the selection of high grade modulators to ensure an accurate, adjustable, and reliable phase-lock modulation solution for CBC technique. The ModBox-CBC is available in the 1 µm and 2 µm range.
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Temperature controllers
Variable Optical Delay Lines (VODL)
Phase Modulator
Optical fiber storage
RF driver
Fiber solutions to develop high-power laser architectures in the 2 µm range
High-energy lasers emitting in the sub-2 µm range find applications in the fields of Directional Infrared CounterMeasures (DIRCM) and Directed Energy Lasers (DEL). Even if still more expensive than the 1 or 1.5 µm lasers, the 2 µm lasers have as a considerable asset to be “eye-safe”, meaning that our eye is sensitive to its beam and instinctively closes itself when touched.
Exail leverages 20 years of experience in manufacturing specialty optical fibers. Its portfolio counts a range of thulium (Tm), holmium (Ho) and Tm/Ho doped fibers for amplifiers and fiber lasers, as well as Fiber Bragg Gratings (FBG), addressing the 2 µm market. They are key components for the development of laser architecture in the 2 µm range that are as efficient as possible, and that can deliver high power (around 200 W).
Exail portfolio also counts high-performance modulation solutions (LiNbO3 modulators and ModBox) and integrated micro-optics benches adapted to this wavelength range.
Why choose us?
Field proven solutions from deep sea to outer space
Exail leverages 30 years of advanced expertise in fiber-optic gyroscopes (FOG), operating from deep sea to outer space. Integrated into the FOGs, Exail photonics components have proven they are resistant to external disruptions such as shocks, extreme temperatures, magnetism and vibrations.
Field proven solutions from deep sea to outer space
Custom solutions
Exail can accommodate various customization requirements. Exail optical components have already proven their relevance for very specific and demanding applications, including inertial fusion facilities, space and quantum technologies.
Custom solutions
Robust in-house manufacturing capabilities
Exail high-end specialty fibers and optical components are produced in environmentally controlled production areas to ensure high proof strength, tight tolerances and a high-quality level. Manufacturing of lithium niobate optical modulators for fiber optic systems is carried out in an ISO 6 cleanroom facility.
Robust in-house manufacturing capabilities
