Planar coupler devices of multimode fiber optics

In this paper we report on investigations of the multimode planar approach to fiber-optic coupler development. The planar approach, which utilizes photolithographic processing, is promising because of its versatility and high reproducibility. Our results indicate that this approach is indeed versatile and may lead to potential savings over conventional fabrication techniques. However, the major problem that remains to be solved is the reduction of interface losses.