Preparation of a main-chain azo polyurethane-urea and its application of Y-branch and Mach-Zehnder thermo-optic switch

A novel main-chain azo polyurethane-urea (MCAPUU) was prepared with chromophore molecule 1,1'-azobisformamide (ABFA), polyether polyol (NJ-220) and isophorone diisocyanate (IPDI). The chemical structures of ABFA monomer and MCAPUU were characterized by the FT-IR and UV-Visible spectroscopy. The thermal and mechanical properties of MCAPUU film were investigated. The refractive index and transmission loss of MCAPUU film were measured at different temperature and different laser wavelength by attenuated total reflection (ATR) technique and the CCD digital imaging devices. The thermo-optic coefficients (dn/dT) of MCAPUU are -4.5429 x 10(-4) A degrees C-1 (532 nm), -5.7943 x 10(-4) A degrees C-1 (650 nm) and -6.6057 x 10(-4) A degrees C-1 (850 nm), respectively. A Y-branch switch and Mach-Zehnder interferometer (MZI) thermo-optic switches based on thermo-optic effect were proposed and the performances of switches were simulated. The results showed that the power consumption of the Y-branch thermo-optic switch is only 0.74 mW. The rising and falling times of Y-branch and MZI switches are 12.0 and 1.8 ms, respectively. The results indicate that the prepared MCAPUU has high potential for the applications of the Y-branch digital optical switch (DOS), MZI thermo-optic switch, directional coupler (DC) switch and optical modulators.