Tunable wavelength filters using polymer long-period waveguide gratings based on metal-cladding directly defined technique
Wang Ji-Hou, Chen Chang-Ming †, Zheng Yang, Wang Xi-Bin, Yi Yun-Ji, Sun Xiao-Qiang, Wang Fei, Zhang Da-Ming
       

(color online) (a) Structural patterns of double gold claddings and waveguide region by microscope (×500), and (b) surface morphology from the gold cladding measured by AFM.