A Planar Waveguide Nd:YAG Laser Using Active Q-Switching of a Hybrid Unstable Resonator

Xu, Jianqiu; Thomson, I.; Valera, J. D.; Baker, H. J.; Russell, A.B.; Hall, D. R.

doi:10.1109/jstqe.2007.897183

Cited by 13 publications

(7 citation statements)

References 14 publications

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“…Therefore, it is not surprising that there is large number of reports on such devices, almost all of which are based on YAG:Nd 3+ [16,[199][200][201][202][203][204][205][206][207][208][209][210][211][212][213][214][215] slab waveguides, largely due to the favorable thermo-mechanical properties of this crystal, which make it suitable for high-power diode pumping. Lasing was also reported for Nd 3+ -doped BK7 glass-based waveguides fabricated by a combination contact bonding and ion exchange [216].…”

Section: Contact and Diffusion Bondingmentioning

confidence: 99%

Optically pumped planar waveguide lasers, Part I: Fundamentals and fabrication techniques

Grivas

2011

Progress in Quantum Electronics

194

102

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Abstract:The tremendous interest in the field of waveguide lasers in the past two decades is largely attributed to the geometry of the gain medium, which provides the possibility to store optical energy on a very small dimension in the form of an optical mode. This allows for realization of sources with enhanced optical gain, low lasing threshold, and small footprint and opens up exciting possibilities in the area of integrated optics by facilitating their on-chip integration with different functionalities and highly compact photonic circuits. Moreover, this geometrical concept is compatible with high power diode pumping schemes as it provides exceptional thermal management, minimizing the impact of thermal loading on laser performance. The proliferation of techniques for fabrication and processing capable of producing high optical quality waveguides has greatly contributed to the growth of waveguide lasers from a topic of fundamental research to an area that encompasses a variety of practical applications. In this first part of the review on optically pumped waveguide lasers the properties that distinguish these sources from other classes of lasers will be discussed. Furthermore, the current state-of-the art in terms of fabrication tools used for producing waveguide lasers is reviewed from the aspects of the processes and the materials involved. 2 1.IntroductionOver the last two decades the field of solid-state planar waveguide lasers has experienced a steady growth, progressing from a laboratory curiosity to an area that demonstrates a broad spectrum of applications, from multiwavelength laser channel arrays for telecommunications to diode-pumped planar structures with multiwatt output powers for sensing and ranging applications. Waveguide lasers are by no means a new field and the first report on such a source dates back in 1961, when laser operation of a waveguide based on an active glass core rod embedded in a low refractive index cladding was demonstrated [1]. However research efforts in the years that followed this report focused primarily on the development of optically pumped laser sources based on high optical quality bulk dielectric laser media in the form of rods and slabs. The merits of the waveguide geometry and the associated optical confinement have been first highlighted in single mode glass optical fibers. Fibers have proven an enabling technology for realization of highly efficient amplifier and laser sources owing to their unrivalled low loss performance and ability to maintain a small spot size and hence high intensities over lengths that are orders of magnitude longer than would normally be allowed by diffraction, [2,3]. Er-doped fiber amplifiers (EDFAs) in particular have directly contributed to the enormous expansion of the optical communications networks that underpin today's internet infrastructure by allowing for signal regeneration and optical data transmission over long distances. The excellent performance of fiber lasers and amplifiers provided motivation and triggered a major techn...

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Section: Contact and Diffusion Bondingmentioning

confidence: 99%

Optically pumped planar waveguide lasers, Part I: Fundamentals and fabrication techniques

Grivas

2011

Progress in Quantum Electronics

194

102

View full text Add to dashboard Cite

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“…We are currently investigating the effectiveness of the mirrors in 200W class cw lasers using planar waveguide gain regions. [1] …”

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confidence: 99%

“…A two-mirror configuration is preferred for ease of alignment and simplicity and previously we have used spherical optics [1], but transverse mode selection has relied on the use of an intracavity slit. More general 2-mirror resonators require at least one toroidal mirror surface, with large curvature (R L ~ 0.2m to >1m) in the lateral direction and small curvature (R T ~ 15 to 50mm) in the transverse direction.…”

mentioning

confidence: 99%

“…More general 2-mirror resonators require at least one toroidal mirror surface, with large curvature (R L ~ 0.2m to >1m) in the lateral direction and small curvature (R T ~ 15 to 50mm) in the transverse direction. For a large core height planar waveguide as in [1], R T and the mirror distance can be chosen to obtain mode selectivity by low-loss coupling of the fundamental mode into the core, combined with spread of higher order modes into the cladding. However, additional selectivity may be available if the transverse size of the toroidal mirror is restricted to form a slit-shaped mirror.…”

mentioning

confidence: 99%

“…These mirrors are produced by a two-step CO 2 laser machining process with high resolution ablative laser cutting [2] and then laser polishing [3], or by vaporization of silica in the CO 2 laser smoothing process at higher than usual power. We have produced mirrors with R T = 32mm and 15mm radius of curvature and 14 mm lateral length for use with the 200µm core height Nd:YAG [1] and a 150µm core Yb:YAG planar waveguide laser respectively. The toroidal mirror for the Nd:YAG resonator has been generated by pulsed laser cutting of a silica substrate with R L = 240mm, using a 45µm beam diameter to generate overall cross-section inset in Fig.1.…”

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confidence: 99%

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Mode-selective toroidal mirrors for unstable resonator planar waveguide and thin slab solid-state lasers

Wlodarczyk

Thomson

Baker

et al. 2009

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference

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An effective method for efficient power extraction from planar waveguide or thin slab solid-state lasers is provided by the hybrid configuration, which combines an unstable lateral resonator with a stable or waveguide resonator in the transverse direction. A two-mirror configuration is preferred for ease of alignment and simplicity and previously we have used spherical optics [1], but transverse mode selection has relied on the use of an intracavity slit. More general 2-mirror resonators require at least one toroidal mirror surface, with large curvature (R L ~ 0.2m to >1m) in the lateral direction and small curvature (R T ~ 15 to 50mm) in the transverse direction. For a large core height planar waveguide as in [1], R T and the mirror distance can be chosen to obtain mode selectivity by low-loss coupling of the fundamental mode into the core, combined with spread of higher order modes into the cladding. However, additional selectivity may be available if the transverse size of the toroidal mirror is restricted to form a slit-shaped mirror. Such mirrors are difficult to fabricate by conventional means.We have developed two new fabrication methods for highly curved toroidal laser resonator mirrors based on laser micromachining of cylindrical substrates that already have the large lateral curvature R T provided by conventional polishing. These mirrors are produced by a two-step CO 2 laser machining process with high resolution ablative laser cutting [2] and then laser polishing [3], or by vaporization of silica in the CO 2 laser smoothing process at higher than usual power. We have produced mirrors with R T = 32mm and 15mm radius of curvature and 14 mm lateral length for use with the 200µm core height Nd:YAG [1] and a 150µm core Yb:YAG planar waveguide laser respectively. -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 Distance, mm Level, µm As fabricated Design curvature Curvature R=32mm a) Overall shape -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 Distance, mm Level, µm As fabricated Design curvature Curvature R=15mm b) Overall shapeFig. 1 Surface profile of Nd:YAG resonator mirror fabricated by the laser cutting and polishing process.Fig. 2 Surface profile of Yb:YAG resonator mirror made by vaporization in laser polishing process.The toroidal mirror for the Nd:YAG resonator has been generated by pulsed laser cutting of a silica substrate with R L = 240mm, using a 45µm beam diameter to generate overall cross-section inset in Fig.1. The central 290µm aperture matches the fundamental mode size, with surrounding rims of reverse curvature and grooves designed to disperse the higher order modes. The cut surface is laser polished in just the mirror area, using a scanned CW laser beam [2], reducing the mirror roughness to ±20nm in this area. Fig. 1 shows both the excellent match to the design curvature and the rapid mode-selecting cut-away at the design 290 µm width. In the alternative process aimed at better lateral smoothness, CW vaporization during smoothing at increased laser...

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Theoretical study of weakly-guided large-mode-area rib waveguides: single-mode condition, birefringence, and supermode generation

Hongtao

et al. 2016

Opt Quant Electron

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A Planar Waveguide Nd:YAG Laser Using Active Q-Switching of a Hybrid Unstable Resonator

Cited by 13 publications

References 14 publications

Optically pumped planar waveguide lasers, Part I: Fundamentals and fabrication techniques

Optically pumped planar waveguide lasers, Part I: Fundamentals and fabrication techniques

Mode-selective toroidal mirrors for unstable resonator planar waveguide and thin slab solid-state lasers

Theoretical study of weakly-guided large-mode-area rib waveguides: single-mode condition, birefringence, and supermode generation

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