Silicon nitride microclips for the kinematic location of optic fibres in silicon V-shaped grooves

Flexible silicon nitride clips are used to hold single mode optical fibres in position in grooves etched in silicon substrates to connect either subsu rface or surface mounted optical components. The fabrication process for th e buried fibre connector requires only one lithographic step, and a silicon substrate coated with a 3 mu m thick silicon nitride film. The light coupl ed between two single mode optic fibres buried in the same V groove has bee n measured as a function of the separation of the ends of the fibres. The Y oung's modulus and mechanical properties of silicon nitride from various so urces have been measured using the clips. In another process using two lith ographic steps a clipped fibre is made having the fibre core level with the silicon surface or up to 20 mu m above it, and the tolerances are sufficie ntly tight for optical system manufacture. Light coupling has been demonstr ated between a semiconductor laser and a fibre. The clip technology is vers atile and tolerant of lateral and angular misalignments during insertion. F abrication and mechanical design rules for the silicon nitride clip technol ogy are summarized, and possible applications in fibre connection, waveguid e sensor and telecommunication systems are discussed.