Direct-write embedded waveguides and integrated optics in bulk glass by femtosecond laser pulses

Embedded waveguides and integrated optical devices are fabricated from a computer-aided design file by scanning the focus spot in amorphous silica, using femtosecond laser pulses (800 nm, <125 fs, at 1 kHz). The effect of laser processing conditions on the optical properties of direct-written waveguides and an unusual laser-induced birefringence in an optically isotropic glass are reported. Several integrated optical devices, including Y coupler, directional coupler, and Mach-Zehnder interferometer, are made to demonstrate the simplicity and flexibility of this technique in comparison to the conventional waveguide fabrication processes. © 2005 Society of Photo-Optical Instrumentation Engineers.