Toward a low-jitter 10 GHz pulsed source with an optical frequency comb generator.

Area of Science:

• Photonics and Optical Engineering
• Quantum Optics
• Laser Physics

Background:

• Optical frequency combs are crucial for precise frequency measurements and timing.
• Electro-optic modulators offer a compact method for generating optical frequency combs.
• Timing jitter in pulse generation limits precision applications.

Purpose of the Study:

• To demonstrate low residual timing jitter in 10 GHz optical frequency comb pulses.
• To analyze the factors contributing to timing jitter in such systems.
• To improve the timing stability of optical frequency combs.

Main Methods:

• Utilizing a doubly-resonant electro-optic modulator for 1.55 µm optical frequency comb generation.
• Analyzing the spectral phase and timing delay of generated pulse trains.
• Investigating the impact of pump laser linewidth on timing jitter.
• Implementing an electronic servo system to stabilize the Fabry-Pérot cavity.

Main Results:

• Demonstrated linear spectral phase with different slopes on either side of the optical spectrum.
• Identified pump laser linewidth as a dominant factor in timing jitter.
• Reduced integrated residual timing jitter from 94 fs to 8 fs by narrowing pump laser linewidth from 10 MHz to 1 kHz.
• Achieved further jitter reduction to 6 fs using electronic cavity stabilization.
• Measured residual phase noise power density of -105 dBc/Hz at 1 Hz offset from the 10 GHz carrier.

Conclusions:

• The spectral phase characteristics of the electro-optic modulator-based comb generator are well-understood.
• Pump laser linewidth is critical for achieving low timing jitter in optical frequency combs.
• Electronic stabilization provides a viable method for further enhancing timing precision.