Si-rich SiNx based Kerr switch enables optical data conversion up to 12 Gbit/s.

Gong-Ru Lin,Chung-Lun Wu,Bo-Ji Huang,Huai-Yung Wang,Yung-Hsiang Lin,Yu-Chieh Chi,Cheng-Ting Tsai,Chih-I Wu,Sheng-Pin Su

doi:10.1038/srep09611

Abstract

Silicon photonic interconnection on chip is the emerging issue for next-generation integrated circuits. With the Si-rich SiNx micro-ring based optical Kerr switch, we demonstrate for the first time the wavelength and format conversion of optical on-off-keying data with a bit-rate of 12 Gbit/s. The field-resonant nonlinear Kerr effect enhances the transient refractive index change when coupling the optical data-stream into the micro-ring through the bus waveguide. This effectively red-shifts the notched dip wavelength to cause the format preserved or inversed conversion of data carried by the on-resonant or off-resonant probe, respectively. The Si quantum dots doped Si-rich SiNx strengthens its nonlinear Kerr coefficient by two-orders of magnitude higher than that of bulk Si or Si3N4. The wavelength-converted and cross-amplitude-modulated probe data-stream at up to 12-Gbit/s through the Si-rich SiNx micro-ring with penalty of −7 dB on transmission has shown very promising applicability to all-optical communication networks.

Highlights

The plasma enhanced chemical vapor deposition (PECVD) grown Si-rich SiNx with excessive Si density of 23.4% is employed to fabricate the rib-type bus and micro-ring waveguides with insertion loss of 3 dB/facet, which exhibits dense crystalline SiQDs buried in the Si-rich SiNx to enhance ultrafast nonlinear Kerr effect, enabling a transient nonlinear refractive index change to achieve cross-wavelength all-optical data conversion at telecommunication wavelengths
The Si-rich SiNx micro-ring with Q 5 1.1 3 104 further enhances the ultrafast nonlinear Kerr effect due to the optical field enhancement of the incoming optical data-stream at its resonant wavelength
The input optical data stream instantly modifies the nonlinear refractive index of the Si-rich SiNx to cause the red-shift of resonant notch, providing a high-speed all-optical data conversion with either preserved or inverted format via the cross-wavelength amplitude modulation effect

Summary

Introduction

With the Si-rich SiNx micro-ring based optical Kerr switch, we demonstrate for the first time the wavelength and format conversion of optical on-off-keying data with a bit-rate of 12 Gbit/s. The field-resonant nonlinear Kerr effect enhances the transient refractive index change when coupling the optical data-stream into the micro-ring through the bus waveguide. This effectively red-shifts the notched dip wavelength to cause the format preserved or inversed conversion of data carried by the on-resonant or off-resonant probe, respectively. To achieve high-speed data transmission, the Si-QD based photonic devices using nonlinear effects such as two-photon-absorption (TPA) and third-order Kerr effects are considered[20]. Even after doping with the SiQDs, the reduced bandgap energy of the Si-rich SiNx is still high enough to suppress the TPA effect

Methods

Results

Conclusion