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Research Highlights, 45° Curved Micro-mirror for Vertical Optical Input/Output in Silicon Photonics Chips

Department of Electronics and Manufacturing

45° Curved Micro-mirror for Vertical Optical
Input/Output in Silicon Photonics Chips

NORIKI Akihiro, AMANO Takeru
Platform Photonics Research Center

MORI Masahiko
Research Strategy Planning Department

Establishment of key technologies for photonics-electronics conversion

We have succeeded for the first time in the world in developing a process for integrating curved micromirrors on photonic chips. This was achieved by introducing curved micromirrors (3D devices) on a photonic chip, on which previously only 2D devices were used. Simulations have confirmed the low loss of optical signals, and actual measurements have demonstrated that the basic properties of the mirrors, such as optical coupling efficiency, are at a practical level.

Vertical optical input/output technology and improvements

In practical applications of silicon photonics, where silicon is used as the optical medium, vertical optical input/output (I/O) offers many advantages in making optical connections, such as allowing flexible I/O placement on the chip surface. AIST developed a relatively simple and inexpensive method to fabricate a planar micromirror, but wafer-level integration/testing, 2D optical I/O placement as a 2D array of mirrors, etc. have not yet been achieved. Moreoever, there was the issue of developing a fabrication method of a curved micromirror which has a potential advantage because it works like a lens and realizes beam-waist conversion, beam-focusing, and/or beam-collimating functions.

Simulation and actual fabrication of curved micromirrors

Simulations of the new three-dimensional micromirror development confirmed that it can couple various types of optical fibers and has the same efficiency over a wide wavelength bandwidth. Based on these results, a design was developed and the developed curved micromirror was integrated on a Si photonic chip equipped with a Si waveguide and spot size converter using semiconductor manufacturing technology fitted for wafer-level manufacturing. Measurements of near-field and far-field patterns showed that the lens function of the mirror is suitable for vertical optical input/output.

Optimize developed technologies to improve efficiency and other characteristics

In the future, we will improve the reproducibility and uniformity of mirror fabrication and establish an optical coupling method that is not affected by polarization. It will be used for efficient vertical optical input/output with various types of single-mode optical fibers and waveguides as one of the core technologies for photonics-electronic conversion in next-generation semiconductors and silicon photonics.

Contact for inquiries related to this theme

Optical Integration Research Team, Platform Photonics Research Center

NORIKI Akihiro, Senior Researcher

AIST Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan

E-mail: M-contact-pprc-ml*aist.go.jp (Please convert "*" to "@".)

Web: https://unit.aist.go.jp/pprc/optic/optic_en.html

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