Ion-implanted polymethyl methacrylate beam splitter/coupler for 155 μm applications

The applicability of layers of ion-implanted polymethyl methacrylate (PMMA) for beam splitting of laser light at the telecommunications wavelength of 1.55 mum is examined. Bulk PMMA is studied, subjected to low-energy (50 keV) silicon ion implantation at various ion fluences in the range from 10(14) to 10(17) cm(-2). The formed ultrathin near-surface ion-implanted layer of a thickness of about 100 nm, buried in a depth of approximately 100 nm, can be used to split (or combine) laser beams at 1.55 microm with a low absorption loss.