All-optical switching in epsilon-near-zero asymmetric directional coupler

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• All-optical switches are crucial for high-speed optical communication networks.
• Existing all-optical switching technologies face limitations in speed and performance.

Purpose of the Study:

• To propose and investigate a novel all-optical switch utilizing an epsilon-near-zero (ENZ) layer.
• To analyze the nonlinear optical properties of the ENZ layer via hot-electron dynamics.
• To demonstrate the device's performance on a silicon nitride platform.

Main Methods:

• Design of an asymmetric directional coupler incorporating an ENZ layer.
• Analysis of nonlinear optical effects in the ENZ layer through hot-electron dynamics.
• Experimental investigation of the all-optical switch performance at a 1.55 μm communication wavelength.

Main Results:

• The switch exhibits an insertion loss of < 2.7 dB and crosstalk of < -18.93 dB.
• A sub-picosecond response time was achieved due to pump-induced refractive index changes in the ENZ layer.
• Successful demonstration of signal light transfer within the optical system.

Conclusions:

• The proposed all-optical switch demonstrates ultrafast response, high performance, and a simple structure.
• This device offers significant potential for future all-optical communication and signal processing applications.
• The use of ENZ materials provides a promising pathway for advanced photonic devices.