In-plane reactive ion etched fibre grooves for optical integration and coupling

Reactive Ion Etching (RIE) is demonstrated as an alternative to wet etching silicon to form optical alignment grooves for optical interconnection in silicon. The dependence of the etched groove shape, aspect ratio and anisotropy as a function of RIE pressure was measured to optimise the operating parameters for forming fibre grooves in silicon. The groove shape was measured as the degree of groove conformance to a semicircular profile. An optimal pressure of 300 mTorr was determined and the undercutting and depth of the etched grooves as a function of photolithography mask width was measured. An optical fibre is mounted into a fibre groove and packaged using wire bonding. This method of optical interconnection and packaging yielded a fibre-to-fibre optical loss of 1.47 dB.