ng-Jin Ju

Poling-induced birefringence phase matching for 1.5-μm-band wavelength conversion in a polymeric rib waveguide

Abstract A birefringence phase-matching (BPM) scheme for second harmonic generation, difference frequency generation (DFG), and their cascading is developed in a polymer rib waveguide. Poling-induced birefringence ( n TM – n TE ) of PMMA:DANS side-chain polymer films showed quadratic increase upon applied DC poling fields, and was controlled for satisfying the BPM. The three conversion processes using the nonlinear coefficient of the d 15 were simultaneously phase matched at the poling field around 150 V/μm when the fundamental guiding modes of a pump (DFG: 0.775 μm, cascading: 1.55 μm) and a signal (∼1.55 μm) waves were used. In addition, a numerical simulation of the DFG including the waveguide losses showed high conversion efficiencies around 0 dB on the conditions: the pump power of 100 mW, the waveguide length around 2 cm, and the waveguide losses of 2 dB/cm, demonstrating that the poling-induced BPM is an effective phase-matching method in the wavelength conversion processes.

New Host-Guest Polymeric System for Thermal Stability Enhancement of Electro Optic Effect

A new host-guest electro optic (EO) polymer, in which a chromophore can be reacted with the polymer main chain during poling to give the corresponding side-chain EO polymer, has been prepared for improving EO effect and its thermal stability. Polyisoimide (PII) synthesized from 2, 2-bis (4-aminophenyl) hexafluoropropane and oxydiphthalic anhydride and Disperse Red 1 (DR1) were used as a host and a guest, respectively. A model compound reaction and Infrared spectra of the host-guest film after annealing at various temperatures show that the reaction between the isoimide groups in PII and the hydroxyl groups in DR1 occurs around 140 °C. The glass transition temperatures of the resulting EO polyamic aicd ester-imide copolymer with 0, 10, 20 and 30 wt. % of chromophore concentration were 275, 219, 160, and 124 °C, respectively. The EO coefficient obtained at a wavelength of 1.55 νm was 5.3 and 10.5 pm/V from the EO polymer film with 20 and 30 wt. % DR1. The EO signals exhibited only a slight decay at high temperature due to the chemical reaction between the host and guest during poling.

SSC-integrated TM mode LD for long-range surface-plasmon-polariton waveguide

We fabricated 1.3µm TM mode LD with integrated SSC. The high polarization ratio of 21dB was obtained between TM and TE mode. SSC supplied good coupling efficiency and alignment tolerance with LR-SPP waveguide. Clear eye opening was observed under 10Gbps NRZ modulation.

Optical and structural characterization of InP nanorods

InP nanorods were chemically synthesized. We investigated the structures of InP nanorods and their optical properties by using UV-VIS spectroscopy, photoluminescence study, powder X-ray diffractometer and transmission electron microscopy. Also, we suggested their photonic applications.