Angularly offset multiline dispersive optical phased array enabling large field of view and plateau envelope

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Semiconductor Devices

Background:

• Optical phased arrays (OPAs) are crucial for beam steering applications.
• Existing OPAs face limitations in field of view (FOV) and intensity stability.
• Silicon nitride photonics offers advantages for integrated optical devices.

Purpose of the Study:

• To propose and demonstrate a novel angularly offset multiline (AOML) dispersive silicon nitride OPA.
• To achieve efficient line beam scanning with an expanded FOV and stable intensity envelope.
• To integrate multiline OPAs using thermo-optic switches for enhanced performance.

Main Methods:

• Fabrication of a silicon nitride OPA with integrated multiline units and a 45° angular offset.
• Utilizing thermo-optic switches based on multimode interference couplers for seamless integration.
• Implementing oblique polishing techniques for angled facet fabrication.
• Engineering delay lines with adjustable lengths for passive wavelength-tunable beam scanning.

Main Results:

• Demonstrated efficient beam scanning across a wide FOV of 152° via wavelength tuning (1530-1600 nm).
• Achieved a plateau envelope with reduced peak intensity fluctuation (2.8 dB) across the large FOV.
• Measured a dispersive scanning efficiency of 0.97°/nm.
• Successfully switched between multiline OPAs for continuous scanning.

Conclusions:

• The AOML OPA design effectively expands the FOV and improves intensity stability for beam scanning.
• Silicon nitride is a suitable material for fabricating advanced OPAs with integrated functionalities.
• The demonstrated OPA technology holds promise for applications requiring wide-angle, stable optical beam steering.