Coherent terabit communications with microresonator Kerr frequency combs

Area of Science:

• Photonics
• Optical Communications
• Quantum Optics

Background:

• Optical frequency combs are key to terabit communications.
• Kerr combs in microresonators offer dense line spacing but suffer from phase noise.
• Phase noise has previously hindered high-speed data transmission.

Purpose of the Study:

• To demonstrate low phase noise in Kerr combs through systematic pump condition adjustments.
• To enable coherent data transmission using advanced modulation formats with Kerr combs.
• To showcase the potential of Kerr combs for chip-scale terabit transceivers.

Main Methods:

• Systematic adjustment of pump conditions to minimize phase noise in Kerr combs.
• Encoding data streams using quadrature phase shift keying (QPSK) and 16-state quadrature amplitude modulation (16QAM).
• Implementing feedback stabilization for enhanced comb performance.

Main Results:

• Demonstrated coherent data transmission of 392 Gbit/s using QPSK and 16QAM.
• Achieved a 1.44 Tbit/s data stream transmission over 300 km with feedback-stabilized Kerr combs.
• Confirmed that low phase noise Kerr combs meet stringent spectral purity requirements for coherent communications.

Conclusions:

• Systematic optimization of pump conditions effectively reduces phase noise in Kerr combs.
• Kerr combs are a viable technology for high-speed, spectrally pure coherent data transmission.
• This work positions Kerr combs as a promising solution for future chip-scale terabit transceivers.