Abstract. Comparative analysis is presented for two alternative ways to create optical waveguide on the base of spatial profiles of refractive index in quartz glass experimentally obtained by femtosecond treatment. Advantages and disadvantages of the two methods in creation of the waveguide core with enhanced refractive index and the cladding with reduced refractive index are discussed. Numerical simulation is employed to analyze the influence of the most significant perturbations observed in the experiment on the basic parameters of the waveguide: the effective refractive index, diameter and shape of the mode distribution, input and output losses for the approval of the mod with standard optical fibers. The following main disturbances affecting the femtosecond record are considered: local decrease in the peak intensity of the laser radiation causing a local reduction of the induced refractive index, and local deviation of the focus point from the desired path for characteristic size of 2 microns. The results of the study can be used to record femtosecond waveguides with reduced losses by scattering, and to increase the repeatability and reliability of the micromachining technology.

Keywords: laser-induced effect, femtosecond record, locally-modified area, induced refractive index, waveguide

References:

1. Osellame R., Cerullo G., Ramponi R. Femtosecond Laser Micromachining Photonic and Microfluidic Devices in Transparent Materials, London, Springer, 2012.
2. Okhrimchuk A.G., Shestakov A.V., Khrushchev I., Mitchell J. Opt. Lett., 2005, no. 17(30), рр. 2248–2250.
3. Streltsov A.M., Borrelli N.F. Opt. Lett., 2001, no. 1(26), рр. 42–43.
4. Williams R.J., Kramer R.G., Nolte S., Withford M.J. Opt. Lett., 2013, no. 11 (38), рр. 1918–1920.
5. McMillen B. et al. Opt. Lett., 2014, no. 12(39), рр. 3579–3582.
6. Dubov M., Boscolo S., Webb D.J. Opt. Mater. Express, 2014, no. 8(4), рр. 1706–1716.
7. Ma Xiao-Song. Nature Photonics, 2014, no. 8, рр. 749.
8. Mermillod-Blondin A. et al. Appl. Phys. Lett., 2008, no. 93, рр. 021921.
9. Okhrimchuk A.G. et al. Opt. Lett., 2009, no. 34, рр. 3881–3883.
10. Bukharin M.A., Khudyakov D.V., Vartapetov S.K. Appl. Phys. A, 2015, no. 1(119), рр. 397–403.
11. Zhang H., Eaton S.M., Herman P.R. Opt. Express, 2006, no. 11(14), рр. 4826–4834.
12. Payne F., Lacey J. Opt. Quantum Electron., 1994, no. 26, рр. 977–986.
13. Melati D., Morichetti F. A. J. Opt., 2014, no. 16, рр. 055502.
14. Semenov A.S., Smirnov V.L., Shmalko A.V. Integral Optics for System of Information Transmission and Processing, Moscow, Radio and Communication, 1990.
15. Osellame R., Taccheo S., Marangoni M., Ramponi R., Laporta P., Polli D., De Silvestri S., Cerullo G. J. Opt. Soc. Amer. B-Opt. Phys., 2003, no. 20, рр. 1559–1567.
16. Ams M., Marshall G.D., Spence D.J., Withford M.J. Opt. Express, 2005, no. 13, рр. 5676–5681.