光學濾波器在光通訊中處理特定頻譜的訊號是不可或缺的；窄瀕濾波器更是特別重要；再者，多波長濾波器的主動元件在通訊系統中較被動元件更強大且多功能。 我們設計且做了第一個利用APLN當作在C band的主動式窄頻寬多波長濾波器。在5公分長的APLN元件，外加約700(V/mm)的電場(設設計值為298V/mm)，能夠同時使得8個電信波長有大於90%以上的穿透率(設計上~100%)，每個波長的頻寬約為0.45nm。我們在一片2cm的串極式APLN晶體，1cm長的波長濾波器接著1cm長的波長轉換器，得到了高度地抑制了邊葉波段的四個窄頻的二倍頻光。Optical Filters are quite dispensibale in optical communication allows the process of signals in special spectrum portions. Narrowband filters are particularly important. Moreover, Active devices with multiple wavelength filter would be much powerful and functional in the communication system than the passive ones. we report the design and first experimental observation of active narrowband multiple wavelength filters in aperiodically poled lithium niobates (APLN) crystals in telecom C band. Simultaneous transmission of >90% (~100% in design) of 8 telecom wavelengths with each a bandwidth of ~0.45 nm was achieved in a 5-cm long APLN device when an electro-optic field of ~700 V/mm (~298 V/mm in design) was applied. We also obtained four peak-narrowed and highly sidelobe-suppressed second-harmonic generation (SHG) signals of four telecom wavelengths from a monolithic LiNbO3 crystal cascading a 1-cm long APLN wavelength filter and a 1-cm long APLN wavelength converter.