Enhancing Optical Nonlinearity in a Nonstoichiometric SiN Waveguide for Cross-Wavelength All-Optical Data Processing

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• 作者：Chung-Lun Wu ; Yung-Hsiang Lin ; Sheng-Pin Su ; Bo-Ji Huang ; Cheng-Ting Tsai ; Huai-Yung Wang ; Yu-Chieh Chi ; Chih-I Wu ; Gong-Ru Lin
• 刊名：ACS Photonics
• 出版年：2015
• 出版时间：August 19, 2015
• 年：2015
• 卷：2
• 期：8
• 页码：1141-1154
• 全文大小：1241K
• ISSN：2330-4022

文摘

Nonstoichiometric SiN_x with enhancing optical nonlinearity is enabled to facilitate the waveguide microring resonator for cross-wavelength all-optical data processing applications. The Si/N composition ratio of the nonstoichiometric SiN_x can be detuned from stoichiometric to Si-rich by adjusting the SiH₄/NH₃ fluence ratios. Under pumping with incoming pulsed data, the comb-like transmittance of the nonstoichiometric SiN_x microring resonator can spectrally red-shift by 100 pm as its effective refractive index changed by more than 1 order of magnitude due to the enhanced nonlinear Kerr effect. The enlarged refractive index of 螖n = 1.6 脳 10^鈥? with increasing nonlinear refractive index to n₂ = 1.6 脳 10^鈥?3 cm²/W at 1550 nm is observed at a Si concentration of 66.2% in the Si-rich SiN_x film. In application, a cross-wavelength all-optical data conversion/inversion processor based on the nonstoichiometric SiN_x microring resonator is presented. The dense nanoscale Si content formed by a higher Si/N composition ratio of the SiN_x contributes to an enhanced Kerr effect based optical nonlinear switching, which enables the optimized 12 Gbit/s all-optical conversion of the pulsed return-to-zero on鈥搊ff-keying (RZ-OOK) data with converted or inverted format. The photon lifetime of 鈭?9 ps in the Si-rich SiN_x microring resonator cavity can support the Si-rich SiN_x all-optical Kerr switch with a maximal bandwidth of up to 50 GHz.