Integrated self-referenced frequency-comb laser based on a combination of fiber and waveguide technology

Area of Science:

• Photonics and Optical Engineering
• Laser Physics and Technology
• Integrated Optics

Background:

• Frequency combs are crucial for precision measurements, but often require bulky and complex setups.
• Self-referenced frequency combs enable direct measurement of the carrier-envelope offset (CEO) frequency, simplifying operation.
• Existing phase-sensing technologies for CEO stabilization typically demand high pulse energies, limiting system miniaturization.

Purpose of the Study:

• To demonstrate the first self-referenced frequency comb system entirely based on guided-wave technology.
• To develop an optically integrated solution for carrier-envelope-offset (CEO) phase stabilization.
• To reduce the pulse energy requirements for phase-sensing in frequency comb lasers.

Main Methods:

• Utilized a passively mode-locked Erbium-fiber laser as the gain medium.
• Integrated a butt-coupled periodically poled lithium niobate (PPLN) waveguide as a phase-sensor.
• Implemented an electronic feedback loop for carrier-envelope-offset (CEO) phase stabilization.

Main Results:

• Successfully demonstrated an optically integrated, self-referenced frequency comb laser.
• Achieved CEO stabilization with a beat signal linewidth of 62 kHz and a signal-to-noise ratio of 40 dB.
• Significantly reduced pulse energy requirements compared to traditional bulk crystal phase-sensors.

Conclusions:

• This work presents the first self-referenced frequency comb system built entirely on guided-wave technology.
• The integrated PPLN waveguide approach offers a compact and efficient method for CEO stabilization.
• The reduced pulse energy requirements pave the way for more accessible and miniaturized frequency comb systems.