Microresonator achieves ultra-efficient optical signal processing

Optical signal processing has the potential to outperform electrical signal processing because of its improved capacity and power consumption. For decades, researchers have been attempting to perfect an integrated nonlinear photonic chip for optical signal processing. However, most chips developed thus far require optical power only attainable with off-chip, bulky lasers or amplifiers, not with on-chip lasers.

Using an integrated microresonator, Stassen et al. demonstrate all-optical wavelength conversion of a high-speed data signal with low operation power at the sub-milliwatt level. Wavelength conversion is crucial because it allows optical routing, which is necessary for optical signal processing in the future all-optical network. Their work is a step towards a fully-integrated chip solution for high-speed optical signal processing.

The authors developed a high-confinement aluminum gallium arsenide (AlGaAs) on-insulator waveguide platform, which provided an ultra-high nonlinear efficiency. They also used a microring resonator with a broad resonance linewidth, which provided field enhancement. This combination of properties allowed the authors to achieve ultra-efficient optical signal processing, with record-low power consumption and high speed data signal operation on the order of 10 gigabits per second.

Author Minhao Pu said their integrated AlGaAs microring resonator platform is not only beneficial to low-power optical signal processing, but also to Kerr frequency comb applications, a type of laser source that relies on efficient nonlinear processes. Next, the authors plan to realize a fully-integrated optical signal processor by heterogeneously integrating both a laser and a nonlinear microresonator on the same chip.

Source: “Ultra-low power all-optical wavelength conversion of high-speed data signals in high-confinement AlGaAs-on-insulator microresonators,” by Erik Stassen, Chanju Kim, Deming Kong, Hao Hu, Michael Galili, Leif Katsuo Oxenløwe, Kresten Yvind, and Minhao Pu, APL Photonics (2019). The article can be accessed at https://doi.org/10.1063/1.5115232 .