3-dB bandwidth enhanced InGaAs PIN photodiode by inductive CPW electrode for datacenter applications

Area of Science:

• Optoelectronics
• Semiconductor Devices
• Microwave Engineering

Background:

• Indium Gallium Arsenide (InGaAs) positive-intrinsic-negative (PIN) photodiodes are crucial for high-speed optical communication.
• Bandwidth limitations in photodiodes hinder data transmission rates.
• Existing bandwidth extension techniques often involve complex fabrication or additional components.

Purpose of the Study:

• To demonstrate a 3-dB bandwidth extension technique for InGaAs PIN photodiodes.
• To investigate the impact of coplanar waveguide (CPW) electrode design on photodiode performance.
• To analyze the role of inductive gains and carrier transit times in bandwidth enhancement.

Main Methods:

• Designing coplanar waveguide (CPW) electrodes to introduce inductive gains.
• Developing an equivalent circuit model that includes photo-generated carrier transit times.
• Numerically analyzing electron and hole transit times.
• Validating the model by comparing extracted RLC parameters with measured frequency response data.

Main Results:

• The proposed CPW electrode design successfully imposed inductive gains.
• The equivalent circuit model accurately predicted the photodiode's frequency response when transit times were included.
• A 3-dB bandwidth extension was achieved, increasing from 48 GHz to over 67 GHz at a -2.5 V bias voltage.

Conclusions:

• Reconfiguring the CPW electrode design is an effective method for extending photodiode bandwidth.
• The inclusion of carrier transit time effects in circuit modeling is essential for accurate performance prediction.
• This technique offers a simple yet powerful approach to enhance the speed of InGaAs PIN photodiodes.