On-chip Mach Zehnder interferometer-based all-optical amplitude regenerator for optical 16-QAM signals

Abstract

We propose an on-chip all-optical multilevel amplitude regenerator scheme over a Mach Zehnder interferometer (MZI) configuration, enabling multiple amplitude-noise suppression on 16-QAM signals. Joint parameter optimization is carried out based on the general nonlinear model of the proposed scheme to significantly reduce the phase distortion caused by the nonlinear interferometer, which is the key to perform the phase preserving operation. The full function of the phase-preserving amplitude regeneration (PPAR) is verified by an experiment on an on-chip nonlinear waveguide with the length of the 2.31 cm. Furthermore, we perform thoughtful investigations on the oscillatory behavior achieved by the silicon MZI regenerator, enabling the full PPAR on 16-QAM signals through the optimized multiple power plateaus. A maximum 1.6 dB improvement of signal quality is achieved by the proposed on-chip amplitude regenerator at the input signal-to-noise ratio (SNR) of 25 dB. The impact from the two-photon absorption (TPA) effect as an positive role in the regenerator is also well discussed.

An Introduction to Nonlinear Integrated Photonics: Structures and Devices

“…Optical signal processing techniques employ a wide range of devices and various nonlinearities to achieve multiple network functionalities. Widely used functionalities demonstrated in nonlinear photonic circuits (PICs) include wavelength [ 31 , 32 , 33 , 34 , 35 ] and format conversions [ 36 , 37 ], routing [ 38 , 39 ], phase-sensitive amplification [ 40 ], optical multiplexing and demultiplexing [ 41 , 42 , 43 , 44 , 45 ], optical memory [ 46 , 47 ], all-optical tunable delay [ 48 , 49 ], and signal regeneration [ 50 , 51 ]. Thus far, most of the existing OSP research has relied on third-order nonlinearities, such as four-wave mixing (FWM), self-phase modulation (SPM), and cross-phase modulation (XPM) [ 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ].…”