Polymeric chemical injection into a water jet to improve cut quality while cutting very brittle materials

The present invention generally relates to fabricating optical integrated circuits. In particular, the present invention relates to efficiently isolating optical integrated circuits with high yields from substrates. 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 water jet cutting system a mixture of water and at least one water soluble polymer is wet injected into a water stream and then a high pressure polymer water jet is used to cut the brittle substrate. The non-rectangular shaped optical integrated circuits are isolated by water jet cutting in a curvilinear manner without fatally damaging adjacent optical integrated circuits.