Electro-optical switching at 1550 nm using a two-state GeSe phase-change layer

Area of Science:

• Photonics and optical engineering
• Materials science for optoelectronics
• Semiconductor device physics

Background:

• Traditional electro-optical switches face limitations in speed and efficiency.
• Existing devices often require larger footprints and longer active lengths.
• The need for compact, low-loss optical switching components is critical for telecommunications.

Purpose of the Study:

• To present and analyze novel designs for electro-optical free-space and waveguided 2x2 switches.
• To explore the use of germanium selenide (GeSe) as a phase-change material for optical switching.
• To demonstrate reduced device dimensions and enhanced performance characteristics.

Main Methods:

• Development of electro-optical switches employing a ~10 nm GeSe film.
• Electrical actuation to induce amorphous-to-crystal phase transitions in GeSe.
• Analysis of device performance at the 1.55 μm telecommunications wavelength.
• Integration of GeSe with III-V prism materials for free-space optics and Si/GeSe/Si structures for waveguide devices.

Main Results:

• Achieved optical switches with two self-sustaining states via GeSe phase transitions.
• Utilized GeSe's low absorption loss and high electro-refraction (Δn ~0.6) at 1.55 μm.
• Designed cascadeable N x M free-space and waveguided switches.
• Demonstrated active lengths 16x shorter than conventional free-carrier devices.

Conclusions:

• The proposed GeSe-based electro-optical switches offer a significant advancement in device miniaturization and performance.
• The phase-change properties of GeSe enable efficient and compact optical switching solutions.
• These devices are suitable for integration into advanced photonic integrated circuits and free-space optical systems.