High-performance thermally-robust C-band GeSi FK electro-absorption modulators on 300-mm silicon photonics platform.

Area of Science:

• Photonics and optoelectronics
• Materials science
• Semiconductor device physics

Background:

• Silicon photonics enables compact optical transceivers.
• Electro-absorption modulators (EAMs) are crucial for high-speed data transmission.
• Germanium-Silicon (GeSi) alloys offer tunable optoelectronic properties.

Purpose of the Study:

• To demonstrate a high-performance, thermally robust C-band GeSi Franz-Keldysh electro-absorption modulator (FK-EAM).
• To evaluate the static and temperature-dependent performance of the GeSi FK-EAM on a silicon photonics platform.
• To establish GeSi EAMs as a viable technology for advanced optical interconnects.

Main Methods:

• Fabrication of a compact GeSi FK-EAM on a 300-mm silicon photonics platform.
• Experimental evaluation of static electrical and optical performance over wide operating ranges.
• Temperature-dependent measurements from 25°C to 85°C.

Main Results:

• Wafer-scale results show an extinction ratio (ER) of 6.44 ± 0.38 dB and transmitter penalty (TP) of 9.25 ± 0.15 dB.
• Best dies achieved insertion loss (IL) of ~5 dB, figure-of-merit (FOM) of 1.23, and TP of 8.8 dB at 1550 nm.
• Stable performance maintained across the wafer from 25°C to 85°C (ER > 6 dB, FOM > 1, TP ~ 9-10 dB) with a red-shift rate of 0.8 nm/°C.

Conclusions:

• The GeSi FK-EAM demonstrates state-of-the-art performance comparable to room-temperature EAMs.
• The device exhibits robust modulation performance and sustained operation at elevated temperatures.
• GeSi EAMs are a key enabling technology for high-speed, low-power silicon-photonic transceivers in demanding environments.