Data from a test bench configured for an atomic clock is shown in FIGS. 5, 6, and 7. A micro-optical bench is made with in-plane micro-fabricated mirrors. The mirrors are made of silicon (Si). FIG. 5 is a photomicrograph of the micro-optical bench. FIG. 6 is a photomicrograph of a lithographically defined grating in the micro-optical bench. FIG. 7 is a photomicrograph of a lithographically defined mirror in the micro-optical bench.

In this realization a silicon reflection grating (center of FIG. 6) reflects and splits a single beam of light into two directions (m=±1) based on the periodicity of the diffraction grating. This light is collected by two silicon mirrors (bottom left and bottom right of FIG. 7) and routed around the chip in clockwise and anti-clockwise directions. The silicon micro-optical bench in the Example is capable of realizing two counter-propagating beams of light.

All publications, patents, and patent applications cited in this specification are herein incorporated by reference in their entirety as if each publication, patent, or patent application were specifically and individually put forth herein.

In this detailed description, reference has been made to multiple embodiments and to the accompanying drawings in which are shown by way of illustration specific exemplary embodiments of the invention. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that modifications to the various disclosed embodiments may be made by a skilled artisan.