Femtosecond laser direct writing is employed for the fabrication of buried tubular waveguides in bulk poly(methyl methacrylate). A novel technique using selective chemical etching is presented to resolve the two-dimensional refractive-index profile of the fabrication structures. End-to-end coupling in the waveguides reveals a near-field intensity distribution that results from the superimposition of several propagating modes with different azimuthal symmetries. Mode analysis of the tubular waveguides is performed using the finite-difference method, and the possible propagating mode profiles are compared with the experimental data.
© 2004 Optical Society of America
(130.2790) Integrated optics : Guided waves
(220.4000) Optical design and fabrication : Microstructure fabrication
(230.7380) Optical devices : Waveguides, channeled
(350.3390) Other areas of optics : Laser materials processing
Arnaud Zoubir, Cedric Lopez, Martin Richardson, and Kathleen Richardson, "Femtosecond laser fabrication of tubular waveguides in poly(methyl methacrylate)," Opt. Lett. 29, 1840-1842 (2004)