Novel directional coupled waveguide photodiode-concept and preliminary results

Area of Science:

• Photonics
• Optoelectronics
• Semiconductor Devices

Background:

• Traditional waveguide photodiodes face limitations in performance and reliability, particularly concerning burnout.
• Understanding photocurrent density profiles is crucial for optimizing photodiode performance.

Purpose of the Study:

• To introduce and characterize a novel photodiode design incorporating a directional coupler and UTC-style photodiode.
• To evaluate the responsivity, output third-order intercept point (OIP3), and capacitance of the new device.
• To compare the failure mechanisms of the novel design against traditional waveguide photodiodes.

Main Methods:

• Fabrication of a novel photodiode integrating a directional coupler with a UTC-style photodiode.
• Characterization of device responsivity at various photocurrents (up to 10 mA).
• Measurement of OIP3 up to 25 mA and 10 GHz, and device capacitance.
• Modeling of capacitance-limited OIP3.
• Comparative analysis of device failure modes with traditional waveguide photodiodes.

Main Results:

• The novel photodiode exhibits 0.88 A/W responsivity and 35 dBm OIP3 at 25 mA.
• Device capacitance was measured and utilized to model the capacitance-limited OIP3.
• Burnout failure was mitigated, occurring away from the device front compared to traditional designs.
• The new design demonstrates effective control over the photocurrent density profile.

Conclusions:

• The novel directional coupler-integrated UTC photodiode offers superior performance and reliability.
• The design successfully addresses burnout issues and provides control over photocurrent density.
• This advancement holds significant potential for next-generation waveguide photodiode applications.