# High Reliability Evaluation and Lifetime Prediction of 50 GHz Athermal AWG Module
## 3 Athermal AWG Fabrication Results  
Based on the principle of temperature compensation and patent described above, a compact athermal AWG module Gaussian-type (130 mm \(\times\) 90 mm \(\times\) 11 mm) was fabricated using 96-channel (50 GHz-spacing) athermal AWG chip technology and PLC manufacturing technology, as shown in Figure 5 below.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Values** \\ \hline Channel spacing & 50 GHz \\ Number of channels & 96 \\ Focal length of slab waveguide: \(L_{f}\) & 26,751 \(\upmu\)m \\ Path length difference of arrayed waveguide: \(\Delta L\) & 30.84 \(\upmu\)m \\ Pitch of adjacent arrayed waveguide: \(D\) & 8.5 \(\upmu\)m \\ Group index of arrayed waveguide at R.T.: \(n_{g}\) & 1.480 \\ Effective index of slab waveguide at R.T.: \(n_{s}\) & 1.454 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Circuit parameters of AWG.  
Figure 5: Appearance of athermal AWG module.  
Based on Telcordia GR-1221-CORE [19] and Telcordia-GR-1209-CORE [20] for passive optical components, reliability tests were performed on athermal AWG modules under the conditions in Table 2 to measure the performance characteristics before and after the test at room temperature.  
Five samples were used for each reliability test to compare the center wavelength and insertion loss values before and after the tests at room temperature. Figure 6 shows the spectra over all channels for the 96-channel (50 GHz-spacing) athermal AWG modules and the spectrum of one of the samples before the test.  
Figure 7 shows the wavelength and the loss variation measured and monitored during the temperature cycling test. The center wavelength shift and insertion loss values of channels 1, 48, and 96 were measured in the temperature cycling test (\(-40\)\({}^{\circ}\)C\(\sim\)85 \({}^{\circ}\)C). Figure 7a shows the temperature dependence of the center wavelength for three wavelengths (1 ch., 48 ch., 96 ch.) of the 96-channel (50 GHz-spacing) athermal AWG module, confirming that the temperature was compensated. Figure 7b shows the temperature dependence of spectrum 48 ch., in which the center wavelength shift at 85 \({}^{\circ}\)C was \(\pm\)0.05 nm. Figure 7c shows the temperature dependence of the center wavelength for the AWG module (1 ch., 48 ch., 96 ch.) between \(-40\)\({}^{\circ}\)C\(\sim\)85 \({}^{\circ}\)C, in which the temperature compensation was less than \(\pm\)0.05 nm. Figure 7d shows that the insertion loss variation was less than \(\pm\)0.5 dB in the range of \(-40\)\({}^{\circ}\)C\(\sim\)85 \({}^{\circ}\)C.  
\begin{table}
\begin{tabular}{c c} \hline
**Item** & **Condition**[19] \\ \hline Vibration & 20 G, 20–2000 Hz \\  & 4 min/cycles, 4 cycles/axis, 3 axis \\  & 25 \({}^{\circ}\)C–65 \({}^{\circ}\)C, 80\%–100\% R.H. \\ Cycling moisture Resistance test & \(-10\)\({}^{\circ}\)C, 10 cycles \\ Temperature cycling test & \(-40\)\({}^{\circ}\)C–85 \({}^{\circ}\)C, 500 cycles \\ High-temperature storage test & 85 \({}^{\circ}\)C, 2000 h \\ Low-temperature storage test & \(-40\)\({}^{\circ}\)C, 2000 h \\ \hline \end{tabular}
\end{table}
Table 2: Reliability test conditions.  
Figure 6: Spectrum of athermal AWG.