Self-oscillating optical frequency comb generator based on an optoelectronic oscillator employing cascaded modulators

Area of Science:

• Photonics and Optical Engineering
• Microwave Engineering
• Signal Processing

Background:

• Optical frequency combs are crucial for precise frequency metrology and high-speed communications.
• Traditional methods for generating ultraflat optical frequency combs can be complex and costly.
• Optoelectronic oscillators (OEOs) offer a promising platform for generating stable microwave signals.

Purpose of the Study:

• To propose and experimentally demonstrate an ultraflat self-oscillating optical frequency comb generator.
• To integrate cascaded modulators within an optoelectronic oscillator loop for comb generation.
• To evaluate the performance of the generated optical frequency combs and microwave signals.

Main Methods:

• Design and implementation of a self-oscillating optical frequency comb generator based on an OEO.
• Incorporation of cascaded modulators within the OEO loop.
• Experimental demonstration of 10 GHz and 12 GHz optical frequency combs.
• Characterization of spectral power variation and single-sideband phase noise.

Main Results:

• Generation of 11 ultraflat comb lines with frequency spacing determined by the OEO oscillation frequency.
• Demonstrated 10 GHz and 12 GHz optical frequency combs with spectral power variations below 0.82 dB and 0.93 dB, respectively.
• Successful generation and evaluation of spectrally pure microwave signals with low single-sideband phase noise (-122 dBc/Hz at 10 kHz for 10 GHz and -115 dBc/Hz at 10 kHz for 12 GHz).

Conclusions:

• The proposed self-oscillating OEO-based generator provides a novel and effective method for producing ultraflat optical frequency combs.
• The demonstrated system enables the generation of high-quality optical frequency combs and spectrally pure microwave signals.
• This technology holds potential for applications in optical communications, sensing, and metrology.