Nd:MgO:LiNbO/sub 3/ channel waveguide laser devices

This work reports continuous laser oscillation around 1.3 m at room temperature in Nd:YAG planar waveguides fabricated by MeV proton implantation. The performance of the waveguide lasers fabricated with different implantation parameters has been studied in terms of the threshold pump powers and slope efficiencies. The development of compact and efficient solid state lasers is becoming an important matter in the field of integrated optics. The waveguide configuration is necessary in applications such as optics communications and information technology due to its size and compatibility with semiconductor lasers and fiber optic technology.1 Optical waveguides doped with rare-earth ions can be used for the development of miniaturized lasers and amplifiers providing high slope efficiency and low pump thresholds.Ion beam implantation has proved to be an effective technique to fabricate optical waveguides in more than 60 materials.2 The damage caused by nuclear collisions during the implantation process reduces the physical density of the crystal, which results in a reduction of the refractive index. The low-density buried layer that is produced at the end of the ion track acts as an "optical barrier" that has a lower refractive index than the substrate.3 Thus, the region between this barrier and the surface is surrounded by regions of lower refractive index and can act as a waveguide. Nd:YAG was the first material in which such a structure was formed by ion implantation and where the suitability of this technique to fabricate waveguide lasers was demonstrated. 4 Laser oscillation in the cw regime in proton and carbon implanted Nd:YAG waveguides at 1064 nm has been recently reported, showing low pump thresholds and high stability.5 This work presents laser emission at 1338 nm obtained from proton-implanted waveguides, which corresponds to the second telecommunication window in silica optical fibers. Characteristics such as pump power thresholds and laser efficiencies are reported, and these data are compared with the performance of Nd:YAG waveguide lasers operating at 1.06 m.Two planar waveguides were fabricated by proton implantation in a 9SDH-2 Pelletron Accelerator using protons of several energies and different total doses. 6 Waveguide #1 was implanted with energies from 1.25 to 1 MeV at a total dose of 6 ϫ 10 6 ions/ cm 2 , while for waveguide #2 the implanted energies were from 1.15 to 1 MeV at an angle of 30°a nd a final dose of 5 ϫ 10 16 ions/ cm 2 . When a waveguide is formed by ion implantation, color centers are generated during the process, which would imply absorption losses in the waveguide.2 Therefore, an annealing step is necessary in order to reduce these losses. In the present work both Nd:YAG waveguides were introduced during half an hour in an open furnace operating at 400°C.To ascertain in which extent the spectroscopic properties of the neodymium ions are affected by the ion implantation process, a cw Ti:sapphire laser, with a tuning range between 750-850 nm, was used as excitation source and laun...

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“…The pump power threshold depends directly on the effective area of the fundamental mode and on the emission cross section by: 9,10 …”

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confidence: 99%

Continuous-wave laser oscillation at 1.3μm in Nd:YAG proton-implanted planar waveguides

Domenech

Vázquez

Flores-Romero

et al. 2005

Applied Physics Letters

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“…The fluorescence was now detected synchronously and recorded by a digital oscilloscope. A single-exponential fluorescence decay was observed, with a lifetime of 114 s, close to that reported for bulk luminescence, 21 indicating that Zn diffusion does not affect the optical properties of the Nd ions.…”

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confidence: 57%

“…The luminescence from the waveguide shown in Fig. 1 is coincident with the luminescence of bulk-doped LiNbO 3 :Nd 3ϩ , 21 having the same polarization and structure. The fluorescence lifetime was measured under pulsed excitation using a MOPO ͑ exc.…”

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confidence: 90%

Continuous wave waveguide laser at room temperature in Nd3+-doped Zn:LiNbO3

Paolo

Cantelar

Pernas

et al. 2001

Applied Physics Letters

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This work reports continuous laser action at room temperature in LiNbO 3 :Nd 3ϩ channel waveguides, fabricated by Zn diffusion. The absorbed pump power at the threshold was 1.25 mW and a slope efficiency of 20% was obtained. With our available pump power the laser could emit up to 0.14 mW without exhibiting any photorefractive damage. © 2001 American Institute of Physics. ͓DOI: 10.1063/1.1427426͔ Lithium niobate is an attractive and widely used active integrated-optical medium due to its excellent electro-optic, acousto-optic, and nonlinear properties. Rare-earth doped LiNbO 3 allows the fabrication of efficient waveguide lasers and amplifiers. 1 The integration of phase or amplitude modulators allows the construction in this material of many interesting systems, including mode-locked or Q-switched laser devices. 2 Neodymium doped LiNbO 3 can be operated in a four level scheme and it was the first rare-earth ion to lead to laser action in this host. 3,4 However, pump induced photorefractive damage limited the laser oscillation to pulsed operation with low efficiencies. A few years later, it was discovered that MgO codoping reduced the photorefractive damage, 5 and more efficient laser oscillation was reported in Nd:MgO:LiNbO 3 . 6,7 The following step in the use of this material has been the generation of devices in waveguide configuration. Several techniques have been used to produce low loss waveguides in LiNbO 3 such as proton exchange, titanium indiffusion or ion implantation, which have provided methods to produce efficient laser operation in Nd-doped LiNbO 3 waveguides. The first waveguide laser was demonstrated by using proton exchange in a Nd:MgO:LiNbO 3 substrate, 8 which was followed by ion implanted and titanium in-diffused efficient channel waveguide laser. 9,10 Nevertheless due to the high density of photons in the waveguide all these devices suffered from photorefractive damage, limiting the performance to pulsed operation or requiring the continuous annealing at high temperature. 11,12 It should be also mentioned that MgO codoping reduces the solubility of Nd ions in LiNbO 3 , then limiting the number of active ions in the host, and it also reduces the optical quality of the crystals. To date cw lasing operation at room temperature was only reported by Amin et al. 13,14 in the Nd-diffused Ti:LiNbO 3 waveguide, using Z-propagating waveguides and a -polarized pump beam in order to minimize the photorefractive damage. Unfortunately with this configuration not only is the pump efficiency reduced ͑the optimum pump in these materials is polarized͒ but also it is not possible to use the highest electro-optic LiNbO 3 coefficient r 33 to integrate active functions within the same optical chip.An alternative possibility in order to use transverse propagation ͑to the z axis͒ keeping a low photorefractive damage could be based in the fabrication of channel waveguides by Zn diffusion. This fabrication technique 15,16 produces waveguides that support both TE and TM modes, regardless of the crystal cut. Also, i...

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“…Its large stimulated emission cross section allows a low laser threshold. Nd-doped crystal and glass amplifiers and lasers at 1060 nm have been widely studied and reported in both bulk materials as well as waveguide structures [15,17,[27][28][29].…”

Section: Host Materialsmentioning

confidence: 99%

“…Neodymium-doped waveguide lasers [27][28][29] and amplifiers [28,29,[31][32][33] are of interest for applications at the ion's specific emission wavelengths and have been widely studied. The trivalent neodymium ion (Nd 3+ ) is arguably the most important active rare-earth ion for the demonstration of significant gain and laser operation due to the large emission cross-section of its four-level transition ( 4 F 3/2 → 4 I 11/2 ) at approximately 1060 nm, resulting in a very low laser threshold.…”

Section: Introductionmentioning

confidence: 99%

Neodymium-doped waveguide amplifiers and lasers for integrated optical applications

Yang¹

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Nd:MgO:LiNbO/sub 3/ channel waveguide laser devices

Cited by 93 publications

References 21 publications

Continuous-wave laser oscillation at 1.3μm in Nd:YAG proton-implanted planar waveguides

Continuous-wave laser oscillation at 1.3μm in Nd:YAG proton-implanted planar waveguides

Continuous wave waveguide laser at room temperature in Nd3+-doped Zn:LiNbO3

Neodymium-doped waveguide amplifiers and lasers for integrated optical applications

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