Agile THz-range spectral multiplication of frequency combs using a multi-wavelength laser

Area of Science:

• Photonics and Optical Engineering
• Nonlinear Optics
• Integrated Photonics

Background:

• On-chip frequency comb sources offer compact, energy-efficient solutions for applications like lidar and telecommunications.
• Existing sources face a trade-off between controllability and bandwidth: microresonator combs lack control, while electro-optic modulator combs have limited bandwidth.

Purpose of the Study:

• To overcome the fundamental trade-off between controllability and bandwidth in on-chip frequency comb generation.
• To develop a method for agile spectral multiplication of narrowband combs.

Main Methods:

• Exploiting nonlinear dynamics of a multi-wavelength laser under modulated optical injection.
• Achieving spectral multiplication at frequency offsets from 26 GHz to 1.3 THz.
• Implementing on-chip control for nano-second switching of frequency offset.

Main Results:

• Demonstrated agile spectral multiplication of narrowband combs, overcoming the controllability-bandwidth trade-off.
• Achieved frequency offsets from 26 GHz to 1.3 THz with nano-second switching capability.
• Developed a scalable approach compatible with generic photonic platforms.

Conclusions:

• The novel agile spectral multiplication technique offers enhanced control and bandwidth for on-chip frequency combs.
• This approach can be scaled to cover several THz and, when combined with THz photomixers, could enable low-cost, compact THz comb sources.
• The technology paves the way for a new generation of terahertz applications.