THz Signal Generator Using a Single DFB Laser Diode and the Unbalanced Optical Fiber Interferometer

Area of Science:

• Optoelectronics
• Terahertz (THz) Technology
• Laser Physics

Background:

• Developing efficient frequency-modulated optical signal generators is crucial for advanced THz applications.
• Existing methods often involve complex setups or limited tunability.
• A single narrowband laser diode combined with an optical fiber interferometer offers a promising alternative.

Discussion:

• The proposed method achieves fast optical frequency sweeps by driving a laser diode with high-amplitude current pulses.
• Modulation frequency is controllable via the optical path difference of the interferometer and the laser diode's sweep rate.
• Analysis covers Michelson and Fabry-Perot interferometers under varying conditions.

Key Insights:

• Demonstrated generation of optical chirp signals using programmable current pulse waveforms for nonlinear optical sweep.
• Experimental validation confirmed signal generation in both microwave (1-30 GHz) and THz (0.1-0.3 THz) bands.
• The system offers a flexible and efficient approach to THz signal generation.

Outlook:

• Further optimization of current pulse shaping could enhance sweep rates and bandwidth.
• Integration into compact THz systems for sensing and communication is a potential future direction.
• Exploring alternative interferometer designs may lead to improved signal quality and broader frequency coverage.