BACKGROUND

The present invention relates to photonics chips and, more specifically, to structures for an optical power splitter and methods of forming a structure for an optical power splitter.

Photonics chips are used in many applications and systems, such as data communication systems and data computation systems. A photonics chip integrates optical components, such as waveguides, optical switches, optical power splitters, and directional couplers, and electronic components, such as field-effect transistors, into a unified platform. Among other factors, layout area, cost, and operational overhead may be reduced by the integration of both types of components on the same chip.

An optical power splitter is an optical component that is used in photonics chips to divide optical power between multiple waveguides with a desired coupling ratio. The same structure may be used as an optical power combiner that combines optical power received from multiple waveguides. Conventional optical power splitter/combiners tend to have a footprint that is larger than desirable and, in addition, may exhibit an insertion loss that is higher than desirable.

Improved structures for an optical power splitter and methods of forming a structure for an optical power splitter are needed.

SUMMARY

In an embodiment of the invention, a structure for an optical power splitter is provided. The structure includes a multimode interference region, a first waveguide core including a portion positioned over the multimode interference region, a second waveguide core including a portion positioned over the multimode interference region, and a third waveguide core including a portion positioned over the multimode interference region. The first waveguide core provides an input port to the optical power splitter, the second waveguide core provides a first output port from the optical power splitter, and the third waveguide core provides a second output port from the optical power splitter.

In an embodiment of the invention, a method of forming a structure for an optical power splitter is provided. The method includes forming a multimode interference region, forming a first waveguide core including a portion positioned over the multimode interference region, forming a second waveguide core including a portion positioned over the multimode interference region, and forming a third waveguide core including a portion positioned over the multimode interference region. The first waveguide core provides an input port to the optical power splitter, the second waveguide core provides a first output port from the optical power splitter, and the third waveguide core provides a second output port from the optical power splitter.

