Characterization and Optimization of a High-Efficiency AlGaAs-On-Insulator-Based Wavelength Converter for 64- and 256-QAM Signals

Abstract

Abstract-In this paper, we demonstrate wavelength conversion of advanced modulation formats such as 10-GBd 64-QAM and 256-QAM with high conversion efficiency over a 29-nm spectral window by using four-wave mixing in an AlGaAs-On-Insulator (AlGaAsOI) nano-waveguide. A thorough characterization of the wavelength converter is reported, including the optimization of the AlGaAsOI nano-waveguide in terms of conversion efficiency and associated bandwidth and the analysis of the impact of the converter pump quality and power as well as the signal input power. The optimized converter enables generating idlers with optical signal-to-noise ratio (OSNR) above 30 dB over a 29-nm bandwidth leading to error-free conversion of 64-QAM and 256-QAM with OSNR penalty below 1.0 dB and 2.0 dB respectively. The generated idlers exhibit an OSNR margin to the chosen forward error correction thresholds of >3 dB and >7 dB for 64-QAM and 256-QAM, respectively, that can be used for transmission after conversion.

III–V/Silicon Hybrid Non-linear Nanophotonics in the Context of On-Chip Optical Signal Processing and Analog Computing

“…The manufacturing capabilities of the CMOS foundries used for silicon photonics enable complex integrated photonic architectures, which have been used for optical signal processing [55,56,62,63], optical computing [4,5], and quantum optics where integration enables high precision and controllability [64]. In contrast, the demonstration of photonic integrated architectures for all-optical signal processing are more challenging and only a few approaches seem to have reached the scale of a non-linear integrated circuit [65][66][67][68][69]. Relying on the higher non-linearity of III-V semiconductor alloys, the hybrid III-V/Si technology turns out highly relevant to provide non-linear elements that can fit in already existing silicon photonic architectures.…”

Nano-engineered high-confinement AlGaAs waveguide devices for nonlinear photonics

“…Figure 5(b) shows the measured FWM conversion efficiency (normalized) as a function of signal wavelengths with pumping at 1567 nm. It is seen that the 660-nm wide waveguide has the lowest GVD value at the pump wavelength and thus exhibits the widest FWM conversion bandwidth of around 160 nm covering the whole C-and L-band, which is suitable for ultra-fast optical signal processing such as wavelength conversions [18], [19] and phase-sensitive amplification [20].…”

High-Quality-Factor AlGaAs-on-Sapphire Microring Resonators

“…Ultrahigh effective nonlinearity was demonstrated for low-loss nano-waveguides in this platform. Since the bandgap of the Al x Ga 1-x As can be engineered by changing the aluminum composition (x) to avoid the nonlinear loss induced by the twophoton absorption in the telecom wavelength range, a variety of nonlinear applications such as frequency comb generation [14], [15], parametric wavelength conversion [16], [17], and supercontinuum generation [18] have been demonstrated in the AlGaAsOI platform. However, the low index oxide layer between the Al x Ga 1-x As and the carrier substrate has strong material absorption at wavelengths longer than 2.5 µm [19], which prohibits extending the operation wavelength range for the nonlinear AlGaAsOI platform into the mid-infrared (MIR) range.…”