Wet injecting fine abrasives for water jet curved cutting of very brittle materials

The present invention relates to methods and systems for isolating non-rectangular shaped optical integrated circuits formed on a brittle substrate. For example, a brittle substrate comprising a plurality of non-rectangular shaped optical integrated circuits is provided on a water jet cutting system. In the cutting head of the water jet cutting system, a mixture of water and abrasive particles is wet injected into a supply of a high pressure water stream. The non-rectangular shaped optical integrated circuits are isolated by water jet cutting in a curvilinear manner without fatally damaging adjacent optical integrated circuits.