In situ measurement of polarization-resolved emission and absorption cross sections of Er-doped Ti:LiNbO_3 waveguides

Notice of Retraction: Strip Waveguide With High Diffusion-Doped Concentration

“…The Er 3+ absorption loss at λ = 1.547 μm is evaluated from the known Er 3+ absorption cross section values and Er 3+ concentration profile given below. The Er 3+ absorption cross section under the TE/TM polarization, named σ T E (λ)/σ T M (λ), is about (1.0/0.6 ± 0.05) × 10 −20 cm 2 at λ = 1.547 μm [6], [16], [17]. The Er 3+ absorption loss L abs along the waveguide length L is given by L abs = 4.343αL [dB], where α is the waveguide-depth-dependent Er 3+ absorption coefficient in unit of cm −1 , given by α(y) = σ i (λ)C Er (y), in which i = TE or TM and C Er (y) is the Er 3+ concentration depth profile given below.…”

“…Fig. 3(b) shows the measured depth profiles of the substrate ions 93 Nb, 16 Fig. 3(b) represent the best Gaussian fits to the experimental curves and the fitting expressions are indicated.…”

“…The polarization state of the signal light was controlled by a polarization controller suitable for the 1.5 μm wavelength region while that of the pump light was by a mechanical one. Because the Er 3+ absorptions upon both the 980 and 1480 nm light are all highly σ -polarized [6], [16], [17], the pumping light with the TE-polarization was concerned for both cases of 980 and 1480 nm pumping scheme considered here. An optical spectrum analyzer was used to measure the signal output.…”

“…It is unfortunate that due to the limited facility available coupled pump power is only 90 mW, where the signal enhancement has a value ∼5 dB and is insufficient to compensate the larger insertion loss and hence we cannot obtain a net gain. Nevertheless, it is possible to give a theoretical prediction on the attainable saturation gain on the basis of the highly simplified Er 3+ three-level system [23] and the known Er 3+ absorption and emission cross section data at both the 1480 and 1547 nm wavelengths [6], [16], [17]. In Fig.…”

Emission and absorption cross section spectra of Er3+ in LiNbO3 crystals codoped with indium

“…Over the past years, much work on this subject has been done for the Er:LN single-crystal [17][18][19][20] or the Ti-diffused Er:LN strip waveguide. [21][22][23][24][25] For the ErIn-codoped LN crystal, however, the relevant study could not be found yet. In this study, we report polarized emission and absorption cross section spectra at all the above-mentioned typical transition wavelength regions of Er 3+ ions in the Er-In-codoped LN crystals, on which we have done the J-O study.…”