Optimal Design of Thin Film Filters for IR Integrated Photonic Amplifiers

This paper addresses in the design of thin film filter for IR broadband integrated photonic amplifiers. A cascaded multilayer medium thin film filter structure is presented. This proposed filter consists of some different filtering unit cells with different central wavelength and bandwidth, and each cell can suppress certain peak gain at a specific wavelength. The intrinsical gain spectrum of amplifier is obtained by solving a set of rate and power propagation equations with finite difference time-domain(FDTD)-based overlapping integral-Runge Kutter(RK) method. The effect of transmittance spectrum of the proposed cascaded multilayer medium thin film filter on flattening gain is discussed. The transmission function of the cascaded multilayer medium thin film filter is obtained. Finally, a real device is fabricated, it is shown that the design is valid.