Gain-switched dual frequency comb at 2 µm.

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Frequency Comb Spectroscopy

Background:

• Optical frequency combs are crucial for precise measurements.
• Generating dual combs with high repetition rates presents challenges.
• Semiconductor lasers offer compact and efficient light sources.

Purpose of the Study:

• To demonstrate a phase-locked dual optical frequency comb in the 2 µm wavelength region.
• To utilize mutually injection locked gain-switched semiconductor lasers for comb generation.
• To enable compressed data acquisition for sensing applications.

Main Methods:

• Employed strained InGaAs multi-quantum-well discrete mode lasers.
• Utilized gain switching to generate two optical frequency combs.
• Achieved mutual injection locking to a common comb line.

Main Results:

• Generated two optical frequency combs centered at 2.002 µm with repetition rates of 2 GHz and 2.0001 GHz.
• Each comb spanned approximately 100 GHz.
• Demonstrated a phase-locked dual frequency comb with 44 unique beating tones.

Conclusions:

• The demonstrated dual frequency comb scheme allows for compressed information capture within a 5 MHz bandwidth.
• Millisecond acquisition times are achievable, beneficial for real-time sensing.
• This technology has potential applications in various sensing fields requiring high precision.