Design and Fabrication of Long Silicon Microring CROWs (Project Report 0642603-Y3)

This NSF-funded project [0642603] is a five-year (60 months) CAREER (Faculty Early Career Development Program) unified research and education development program, with a focus on the physics and applications of optical waveguiding in the CROW (Coupled Resonator Optical Waveguide) device structure. The CROW structure is suitable as the foundation of this project because it offers a very high four-wave mixing nonlinearity based on the slow-light effects on each of the pump, signal and idler modes. Since the output depends quadratically on the propagation length (in the low power regime), it is important to realize long CROWs.

Synthesis and characterization of electro-optic polyurethane-imide and fabrication of optical waveguide device

The novel electro-optic (EO) polymers of fluorinated cross-linkable Y-type polyurethane-imides (PUI) were designed and synthesized by polycondensation of second-order non-linear optical azo-based chromophores, phenyl diisocyanate, and aromatic dianhydride. Molecular structural characterization for the resulting polymers was achieved by proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, elemental analysis, and gel permeation chromatography. The resulting polymers exhibited good film-forming properties, high glass transition temperature in the range from 186°C to 198°C and thermal stability up to 300°C, high EO coefficient ( γ33 = 43–60 pm/V) at 1550 nm wavelength, good stabilization of electrically induced chromophore dipole alignment and low optical propagation losses in the range of 1.5–1.7 dB/cm at 1550 nm, which are suitable for the EO modulators. Using the synthesized EO PUI as the active core material and of a fluorinated polyimide as cladding material, we have designed and fabricated the high-performance polymer waveguide Mach-Zehnder EO modulators. Obvious modulation was observed by application of ac voltage signal to the EO modulators.

Metal-cladding directly defined active integrated optical waveguide device based on erbium-containing polymer

The Er-containing polymer is synthesized by free-radical polymerization. Based on the copolymer, metal-cladding directly defined waveguide technique is proposed. The technique is advantageous to realize the multi-functional integrated circuits.