High-modulation efficiency operation of GaInAsP/InP membrane distributed feedback laser on Si substrate

Area of Science:

• Optoelectronics
• Materials Science
• Photonics

Background:

• Distributed feedback (DFB) lasers are crucial for optical communication.
• Silicon photonics offers advantages for integrated optical devices.
• Membrane structures can enhance laser performance through improved optical confinement.

Purpose of the Study:

• To investigate the direct modulation characteristics of a membrane DFB laser on a silicon substrate.
• To evaluate the performance metrics, including modulation bandwidth and efficiency.
• To compare the achieved efficiency with existing DFB laser technologies.

Main Methods:

• Fabrication of a membrane DFB laser on a silicon substrate.
• Characterization of optical confinement factor in the membrane structure.
• Small-signal modulation measurements to determine bandwidth and efficiency.

Main Results:

• A strongly index-coupled DFB laser (κ(I) = 1500 cm(-1)) was fabricated with an 80 µm cavity length and 270 µA threshold current.
• A -3dB bandwidth of 9.5 GHz was achieved at 1.03 mA bias current.
• A modulation efficiency of 9.9 GHz/mA(1/2) was recorded, representing the highest value reported for DFB lasers.

Conclusions:

• The membrane DFB laser on silicon exhibits excellent direct modulation characteristics.
• Enhanced optical confinement in the membrane structure is key to achieving high performance.
• The demonstrated device sets a new benchmark for DFB laser modulation efficiency, promising for high-speed optical systems.