Diffusion Properties of Tm³⁺ in Congruent LiNbO₃ Crystal

Abstract

profiles, characteristic diffusion parameters such as diffusivity, diffusion constant, activation energy, solubility, solubility constant, and heat of solution were obtained and discussed in comparison with the case of Er 3+ diffusion. In comparison with Er 3+ diffusion, the Tm 3+ diffusion shows similar anisotropy and temperature dependence of solubility. In the aspect of diffusivity, under lower temperature the Tm 3+ has a lower diffusivity than the Er 3+ , and their diffusivity difference reduces with the increased temperature and becomes null at 1130°C.

Diffusion Properties of Scandium in Lithium Niobate Crystal

“…In parallel, our previous work has revealed that both n o and n e do not change with the bulk‐doped Er 3+ concentration (0–3.0 mol% in crystal) within the experiment error 1 × 10 −3 . Moreover, an independent study on Er 3+ diffusion‐doping into LN shows that the contribution is <1 × 10 −3 for n o and <1.7 × 10 −3 for n e for the considered Er 3+ concentration up to 1.4 mol%, and similar result was also obtained in the case of Tm 3+ diffusion‐doping . One may thus conclude in combination with the present result of Sc 3+ doping that the rare‐earth dopant has little contribution to the substrate index regardless of diffusion‐doping or crystal‐growth incorporation method.…”

“…Similar little contribution to the LN substrate index was also observed for other rare‐earth dopants such as Er 3+ , Yb 3+ , Tm 3+ , whether the ion is incorporated by homogeneous growth‐doping or inhomogeneous diffusion‐doping method. For the homogeneous growth‐doping case, Fedorov et al .…”

Er3+ diffusion in LiTaO3 crystal

“…By taking into account that a longer duration was adopted for a lower temperature while a shorter duration was adopted for a higher temperature (see Table 1), one may conclude that the higher the diffusion temperature, the more serious the Li 2 O out-diffusion, and Li 2 O out-diffusion depends on more the temperature than the duration. Similar result was also obtained for Er 3+ or Tm 3+ diffusion in LN [19,24].…”

“…One can see that the Ti 4+ -induced index increment in LT is much larger than the contribution of Er 3+ dopant. Therefore, the Er 3+ doping contribution to the index increment in the Ti-diffused LT waveguide is minor in comparison with the Ti 4+ doping contribution and can be ignored (this is also the case for LN [19]). Similar small contribution of rare-earth doping to the substrate index was also observed for Er 3+ -or Tm 3+ -doped LN regardless of the incorporation method by either crystal growth [24,25] or diffusion [19,26].…”

“…To fabricate a device with optimized performance, it is crucial to have the knowledge of diffusion properties. For the LN crystal, a number of papers have been published to report the diffusion properties of rare-earth ions (Er 3+ , Tm 3+ , Sc 3+ ) [15][16][17][18][19][20] and transition metal ion Zr 4+ [21]. For the LT crystal, however, the relevant knowledge could not be found yet.…”