A simple technique for suppressing Li2O out-diffusion in Ti : LiNbO3 optical waveguide

Abstract

Li2O out-diffusion in Ti-diffused LiNbO3 optical waveguide was suppressed by annealing a LiNbO3 y-cut substrate in Li2CO3 powder prior to the Ti-diffusion process. The waveguide, made of the substrate annealed at 600 °C for 72 h, supported single TE and TM modes without any out-diffusion modes for 0.6328-μm light propagation.

Integrated Optical Devices in Lithium Niobate

“…1. Li,0 outdiffusion [Miyazawa 1977;Burns et al 1978;Ranganath and -2 * -Wang 1979] 2. Phase transformation [Vahey 1980] 3.…”

“…As a result, a guiding layer capable of supporting a large number of unwanted modes is formed. This problem can be solved by diffusing Ti in the presence of LiNb0 3 powder [Burns et al 1978a;Ranganath and Wang 1979], Although LiC0 3 has been used successfully, it requires longer compensation time [Miyazawa et al 1977].…”

Observation of unusual temperature-dependent stripes in LiTaO3and LiTaxNb1−xO3crystals with near-zero birefringence

“…In order to obtain stoichiometric crystals, vapour transport equilibration (VTE) has proved successful: here the congruent crystal is surrounded by an Li 2 O-rich atmosphere at high temperature and this allows Li 2 O to diffuse into the crystal in order to increase the lithium concentration. This is often carried out for LiNbO 3 (Miyazawa et al, 1977;Holman et al, 1978;Bordui et al, 1992;Cheng et al, 1995;Chen et al, 2002;Liang et al, 2004;Zhang et al, 2007;Hua et al, 2008) but less often for LiTaO 3 (Tian & Gopalan, 2004). In order to determine the composition of VTE-treated crystals several methods have been established, for example using ultraviolet absorption-edge measurements (Bä umer, David et al, 2003) or Raman powder spectroscopy (Scott & Burns, 1972).…”

Ti-Diffused LiNbO3 Waveguides and Modulators

“…-Ti diffusion in Li 2 O rich atmosphere [35,36], -annealing LiNbO 3 substrates in Li 2 CO 3 or LiNbO 3 powder before Ti diffusion [37][38][39][40] or after Ti diffusion [41], -Mg diffusion before Ti diffusion [42]. Figure 7 shows E 2 (n e ) mode nearfield patterns in the -y-cut LiNbO 3 waveguide, fabricated by 8 μπι wide and 50 nm thick Ti metal diffusion at 1050°C for 5 hours.…”