Improvement on tandem-type ultra-high-density multi/demultiplexer performance for use in future super-dense photonic network

我们的目的是通过金属掩膜在紫外激光下的光致折射率变化来减少串联型超高密度多/解复用器中使用的主、次awg的串扰。金属掩模制作工艺：我们提出了一种金属掩模制作工艺，使用喷墨打印机绘制掩模图案，并使用复印机将其固定在抗蚀片上。该方法的优点是制造过程短，约10分钟，成本较低。初级AWG的相位误差测量：我们发现，当所使用的光源仅覆盖AWG透射谱中两个连续峰的两个窄光谱区域时，采用光学低相干干涉法获得的AWG干涉图被分解。该方法成功地用于测量间隔为1太赫兹的主AWG的相位误差分布，其中1.3 μm和1.5 μm led的光组合在一起以两个峰覆盖光谱。我们利用相位误差数据为AWG制作了金属掩模，成功地将频谱中的旁瓣减小了7 dB.3。二次awg的相位误差测量：我们成功地测量了窄通道间距awg的相位误差分布，在频域精度为0.05 rad。这是通过以50nm/s的速度扫描激光频率并通过平衡检测方案去除激光强度噪声来实现的。降低超高密度串联多/解复用器：我们用上述制造工艺为二次awg制造了金属掩模，并成功地将其中央阵列波导周围的副瓣串扰降低到-39 dB。通过将它们与相位补偿的初级AWG相结合，与先前报道的系统相比，1000通道多/解复用器的累积串扰降低了5db。

Our aim was to reduce the crosstalk of primary and seconday AWGs used in a tandem-type ultra-high density multi/demultiplexer by means of photoinduced refractive index change under UV laser light through metal masks.1.Metal mask fabrication process : We proposed a metal mask fabrication process employing an inkjet printer to draw the mask pattern and a copy machine to fix it on a resist sheet. The advantage of the method is a short fabrication process for around 10 minutes and a lower cost.2.Phase error measurement of primary AWG : We found that an interferogram obtained from an AWG with optical low coherence interferometry is decomposed when the employed light source covers only two narrow spectral regions at two successive peaks in its AWG transmission spectrum. This was utilized successfully for measuring the phase error distribution of a 1-THz-spaced primary AWG, where the lights from 1.3 and 1.5 μm LEDs were combined to cover the spectrum with two peaks. We fabricate the metal mask for the AWG from the phase error data and succeeded in reducing the sidelobe in the spectrum by 7 dB.3.Phase error measurement of secondary AWGs : We have succeeded in measuring the phase error distributions of narrow-channel spacing AWGs with an accuracy of 0.05 rad in the frequency domain. This was achieved by sweeping the laser frequency at 50nm/s and by removing the laser intensity noise with a balanced detection scheme.4.Reduction of an ultra-high density tandem multi/demultiplexer : We fabricated metal masks for the secondary AWGs with the above fabrication process and succeeded in reducing the sidelobe crosstalk to -39 dB around their central arrayed waveguides. By combing them with the phase-compensated primary AWG, the accumulated crosstalk of the 1000-channel multi/demultiplexer was reduced by 5 dB as compared with the system previously reported.