Abstract: This optical coupler for coupling a plurality of visible light beams having different wavelengths includes: a substrate made of a material different from lithium niobate; and an optical coupling function layer formed on a main surface of the substrate. The optical coupling function layer includes: two multimode-interference-type optical coupling parts; optical-input-side waveguides and an optical-output-side waveguide connected to one multimode-interference-type optical coupling part, and optical-input-side waveguides and an optical-output-side waveguide connected to the other multimode-interference-type optical coupling part. The multimode-interference-type optical coupling parts, the optical-input-side waveguides, and the optical-output-side waveguides are made of a lithium niobate film.

Abstract: An address translation buffer control system includes multiple prioritized address translation buffers and circuitry for changing the contents of the buffers. When a desired address translation pair is not present in the buffer having the highest priority, the contents of the highest priority buffer are replaced with contents from a lower priority buffer. If a desired address translation pair is not present in any buffer, the contents of the lowest priority buffer are replaced.