Low-Loss Ti: LiNbO/sub 3/ Waveguide Bends at Lambda = 1.3 µm

Low-loss waveguide bends are necessary for many proposed integrated optical circuits. The bend loss associated with an S-shaped transition connecting offset 6 µm wide titanium-indiffused lithium niobate strip waveguides has been measured as a function of transition length and initial Ti metal thickness for 1.3 µm wavelength. Losses as low as 0.2 +- 0.2 dB have been achieved for a transition between offset parallel waveguides with a 0.1 mm lateral and 3.25 mm longitudinal separation. The bend loss is shown to be strongly dependent on the mode confinement and less sensitive to the shape of the transition curve.