Combined reflector and DOE couple light into or out of optical circuit

Dec. 1, 2009
It is sometimes necessary to couple light into or out of a silicon (Si) optical circuit (for example, from a laser diode or into a fiber or waveguide) in a no-coplanar manner, usually in a direction perpendicular to the plane of the optical circuit.

It is sometimes necessary to couple light into or out of a silicon (Si) optical circuit (for example, from a laser diode or into a fiber or waveguide) in a no-coplanar manner, usually in a direction perpendicular to the plane of the optical circuit. This is conventionally done with a 45° microprism and a separate lens (left). Researchers at National Central University (Jhong-li, Taiwan) and National Dong Hwa University (Hualien, Taiwan) have simplified this arrangement by combining an integrated Si 45° microreflector with a focusing diffractive optical element (DOE) etched on the surface of the microreflector (right).

The angled Si reflector is 216 µm high and is fabricated by anisotropic wet etching. The DOE has a focal length of 150 µm and is created by dry etching, with a minimum 0.71 µm linewidth; a final gold plating increases reflection efficiency. The DOE has an elliptical off-axis design to compensate for astigmatism, producing a 15-µm-diameter spot at best focus and a 20-µm-or-less spot throughout a 600 µm focal depth. Both the reflector and DOE can be monolithically integrated using standard lithographic techniques. Contact Mount-Learn Wu at [email protected].

Sponsored Recommendations

March 31, 2025
Enhance your remote sensing capabilities with Chroma's precision-engineered optical filters, designed for applications such as environmental monitoring, geospatial mapping, and...
March 31, 2025
Designed for compatibility with a wide range of systems, Chroma's UV filters are engineered to feature high transmission, superior out-of-band blocking, steep edge transitions...
March 31, 2025
Discover strategies to balance component performance and system design, reducing development time and costs while maximizing efficiency.
March 31, 2025
Explore the essential role of optical filters in enhancing Raman spectroscopy measurements including the various filter types and their applications in improving signal-to-noise...

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!