A first optical coupler is configured to direct optical signals from an optical fiber onto one or more first optical channels located on a semiconductor chip, wherein the one or more first optical channels have dimensions that are within a specified tolerance of the dimensions of the optical fiber. One or more second optical couplers are configured to direct the optical signals from the one or more first optical channels to one or more second optical channels located on the semiconductor chip, wherein the one or more second optical channels have a specified sub-micron size.