Abstract

Wavelength-independent, polarization-insensitive, compact 3dB optical power splitters are key components in many photonic integrated circuits, such as preamplified lightwave receivers using a Bragg reflection grating-folded noise filter [1], balanced coherent lightwave receivers [2],[3], and optical switches [4], Due to the large size and difficulties in controlling the split ratio of directional couplers, other devices such as polarization-insensitive zero-gap two-mode or multimode interference couplers [5] have been reported. Recently, using a planar slab waveguide as a free-space radiation region, N X N star couplers [6] and 1 × N optical power splitters [7] have been demonstrated. Here, we present an InP-based wavelength-independent, polarization-insensitive, 3dB (2 × 2) optical power splitter using the free-space radiative input-output coupling, which we believe offers a compact and robust integrable element for photonic integrated circuits.

© 1994 Optical Society of America