Single-Chip Ring Resonator-Based 1 × 8 Optical Beam Forming Network in CMOS-Compatible Waveguide Technology

Optical ring resonators (ORRs) are good candidates to provide continuously tunable delay in optical beam forming networks (OBFNs) for phased array antenna systems. Delay and splitting/combining elements can be integrated on a single optical chip to form an OBFN. A state-of-the-art ring resonator-based 1times 8 OBFN chip has been fabricated in complementary metal-oxide-semiconductor-compatible waveguide technology. A binary tree topology is used for the network such that a different number of ORRs is cascaded for delay generation at each output. In this letter, the principle of operation is explained and demonstrated by presenting some measurement results on the 1times 8 OBFN chip.