Abstract: A Mach-Zehnder interferometer (MZI) incorporates a tunable multimode interference (MMI) coupler comprising a tunable MMI coupler with a tuning electrode on a surface of a tunable MMI region and an electrically insulating region provided within the tunable MMI region. The MMI region is tunable in response to detection of a photocurrent by a photodetector section. Such a tunable MZI is particularly advantageous in enabling a split ratio of an optical splitter, the split ratio and the splitter to be controlled in a particularly efficient manner.

Abstract: An Mach-Zehnder interferometer (500) incorporates a tunable multimode interference coupler comprising a tunable MMI coupler (504) with a tuning electrode (524) on a surface of a tunable MMI region (516) and an electrically-insulating region provided within the tunable MMI region. The MMI region is tuned in response to detection of a photocurrent measured by integrated photodetector section (510, 512). Such a tunable MZO is particularly advantageous in enabling a controlled split tio of an optical splitter.

Abstract: An optical interface arrangement includes a tile carrying an optical component which is mounted substantially at right angles to a closely adjacent circuit board which carries an electrical circuit. The circuit board has an electrically conductive track extending to an edge of the board adjacent to an edge of the tile. The edge surface of the tile has a localized recess carrying an electrically conductive material which extends across the thickness of the tile and along a major surface of the tile to connect with the optical component. A short bondwire is provided which links the electrically conductive material in the recess to the adjacent electrically conductive track on the circuit board.