An optical transceiver includes at least one light source and at least one detector mounted on the same surface of the same substrate. The detector is to receive light from other than a light source on the surface. At least one of the light source and the detector is mounted on the surface. An optics block having optical elements for each light source and detectors is attached via a vertical spacer to the substrate. Electrical interconnections for the light source and the detector are accessible from the same surface of the substrate with the optics block attached thereto. One of the light source and the detector may be monolithically integrated into the substrate.