Temperature-Insensitive Dual-Comb Filter Based on Multimode Interference Ti : LiNbO$_{3}$ Waveguide

Nonperiodic Oscillation With Wavelength of Mode Guided in a Special Ti-Diffused $\hbox{LiNbO}_{3}$ Waveguide Structure

“…First of all, we can exclude several possibilities, such as the coupling between the strip and the planar waveguides (because the light power does not lose from the strip waveguide except for the usual waveguide loss), the coupling among the strip waveguides (because the separation each other is large enough, i.e., 200 m), and the interaction between the TE and TM modes. The observed waveguiding characteristic is very similar to that of MMI, which was observed in a usual multimode Ti:LN strip waveguide [9], [10]. However, the waveguiding characteristic here appears to take place in a single-mode waveguide.…”

“…5 depicts the evolution along the propagation direction z of TM mode field distribution in the width direction of the usual MMI Ti:LN strip waveguide. W eff and L c denote the effective waveguide width and the wavelength-dependent coupling length between the two lowest order modes in the waveguide, respectively, and L c % 4N eff ðW eff Þ 2 =ð3Þ [9], where N eff and are the effective refractive index and the wavelength of input beam, respectively. For a given wavelength, the input field profile is reproduced in single-mode or two-mode image at periodic intervals along the propagation direction z.…”