Optical frequency comb and picosecond pulse generation based on a directly modulated microcavity laser

Area of Science:

• Photonics and Laser Technology
• Semiconductor Lasers
• Nonlinear Optics

Background:

• Directly modulated semiconductor lasers are crucial for optical communications.
• Microcavity lasers offer unique properties due to their small size and high Q-factor.
• Generating optical frequency combs (OFCs) and ultrashort pulses is essential for various applications.

Purpose of the Study:

• To experimentally demonstrate optical frequency comb (OFC) and picosecond pulse generation.
• To leverage the high electro-optic modulation response of a directly modulated AlGaInAs/InP square microcavity laser.
• To achieve power-efficient OFCs with good flatness and ultrashort optical pulses.

Main Methods:

• Direct modulation of an AlGaInAs/InP square microcavity laser with a sinusoidal signal.
• Utilizing optical injection locking to enhance the number of comb lines by suppressing nonlinear dynamics.
• Employing dispersion compensation and self-phase modulation in nonlinear fiber for pulse compression.

Main Results:

• Generation of power-efficient OFCs with good flatness and 10 optical tones spaced at 8 GHz with <3 dB power fluctuation.
• Enhancement of comb line number to 20 through optical injection locking.
• Obtaining a 6.8 ps transform-limited pulse and subsequent compression to 1.3 ps.

Conclusions:

• Directly modulated microcavity lasers are a viable platform for generating high-quality OFCs and ultrashort pulses.
• The demonstrated technique offers a power-efficient and scalable approach for integrated photonic applications.
• This work paves the way for advanced applications in spectroscopy, metrology, and high-speed optical communications.