Migration and refractive index control in phosphate glasses by femtosecond laser induced element redistribution

Autor: Macías-Montero, M., Moreno-Zarate, Pedro, Dias, A., Ariza, Rocío, Sotillo, Belén, Fernández, Paloma, Serna, Rosalía, Solís Céspedes, Javier
Rok vydání: 2019
Zdroj: Digital.CSIC. Repositorio Institucional del CSIC
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Popis: USTS 2019, Madrid, Spain, 06 - 08 November, 2019
Femtosecond laser induced element redistribution (FLIER) processes in glass (see the review in Ref. [1]) is an interesting route to produce of photonic devices. Recent FLIER investigations have shown how to produce efficient photonics devices, such as waveguides [2,3], optical amplifiers, and lasers [4]. These works effectiveness rely on the addition of a small amount of a glass modifier that act as a refractive index carrier and a fast diffusing element (usually an alkali ion, like Na+ or K+). Upon fs-laser irradiation, cross migration of both types of glass modifier ions occurs, producing a significant refractive index contract that enables the production waveguides. In this work, experimental conditions are varied to stablish a solid control of the ion migration, and hence, of the refractive index contrast obtained via FLIER. In order to produce optical waveguides, a modified phosphate glass is used. The modification is induced by the addition of small amounts of La+ (index carrier) and K+ (fast diffusion ion) in the form of oxides. Structures are created using 350 fs-laser pulses, operating at 500kHz repetition rate and 1030 nm [5]. Morphological and compositional characterization is carried out by optical microscopy and energy-dispersive X-ray spectroscopy respectively. Performance of the waveguides produces is also evaluated [6]. Results show that it is possible to control the refractive index between 5·10-3 to 1.5·10-2 by tuning the writing velocity of the devices. Simultaneously, mode field diameters (MFD) measured at the exit of waveguides are also controllably tuned, ranging values from 6 to 18 ¿m. The use of a velocity ramp enables the production of tapper structures that are able to convert MFDs with low losses. These results show that the experimental approach is adequate to produce highly versatile and efficient photonic devices. Figure. (a) Optical cross-section images of waveguides written at the indicated velocities. (b) Propagated mode images at 1640 nm. (c) Mode field diameter versus writing velocity. Notes and References 1 Fernandez, T. T. ; Sakakura, M.; Eaton, S. M.; Sotillo, B.; Siegel, J.; Solis, J.; Shimotsuma, Y.; Miura, K. Prog. Mater. Sci. 2018, 94, 68¿113 2 Toney Fernandez, T.; Haro-González, P.; Sotillo, B.; Hernandez, M.; Jaque, D.; Fernandez, P.; Domingo, C.; Siegel, J.; Solis, J. Opt. Lett. 2013, 38, 5248¿51 3 Del Hoyo, J. ; Vazquez, R. M.; Sotillo, B.; Fernandez, T. T.; Siegel, J.; Ferna¿ndez, P.; Osellame, R.; Solis, J. Appl. Phys. Lett. 2014, 105, 131101 4 del Hoyo, J. ; Moreno-Zarate, P.; Escalante, G.; Valles, J. A.; Fernandez, P.; Solis, J. J. Light. Technol. 2017, 35, 2955¿2959 5 Dias, A.; Muñoz, F.; Alvarez, A.; Moreno-Zárate, P.; Atienzar, J.; Urbieta, A.; Fernandez, P.; Pardo, M.; Serna, R.; Solis, J. Opt. Lett. 2018, 43, 2523 6 Moreno-Zarate, P.; Gonzalez, A.; Funke, S.; Días, A.; Sotillo, B.; del Hoyo, J.; Garcia-Pardo, M.; Serna, R.; Fernandez, P.; Solis, J. Phys. status solidi 2018, 1800258, 1¿6
Databáze: OpenAIRE
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