C-band 33-GHz high flatness photon-photon resonance directly modulated semiconductor lasers

Area of Science:

• Photonics
• Semiconductor Lasers
• Optical Communications

Background:

• Directly modulated lasers (DMLs) utilizing the photon-photon resonance (PPR) effect (PPR-DMLs) offer high modulation bandwidth.
• However, uncontrolled PPR amplitude causes frequency-dependent intensity variations, degrading broadband system consistency.

Purpose of the Study:

• To propose and experimentally demonstrate a novel method for flattening the frequency response of InP-substrate-based PPR-DMLs.
• To maintain or enhance modulation bandwidth while achieving a flat frequency response.

Main Methods:

• Development of a new technique to control and flatten the frequency response of PPR-DMLs.
• Experimental demonstration using InP-substrate-based lasers operating at 1553.92 nm.

Main Results:

• A high-flatness large-bandwidth directly modulated laser (HFLB-DML) was realized.
• Achieved a ±2 dB response flatness across a 15-32 GHz frequency range.
• Demonstrated 12 mW output power and a 49 dB side-mode suppression ratio (SMSR).

Conclusions:

• The HFLB-DML exhibits an excellent flat frequency response exceeding 30 GHz.
• This technology is highly promising for broadband, high-fidelity microwave photonic systems.
• The proposed method effectively addresses the broadband consistency limitations of PPR-DMLs.