On-Chip Photonic Filter Design via Objective-First Algorithm

We propose and demonstrate compact on-chip optical filters with ultra-high efficiencies, which are designed via the recently-emerged objective-first inverse design algorithm. The all-dielectric high-pass, low-pass and all-pass filters presented in this study operate within the telecommunication wavelength spectrum of 1260 - 1625 nm. The high-pass filter shows an outstanding performance for the transmission efficiency higher than the frequency of 210 THz and an effective suppression of the other spectral region. Also, the proposed low-pass filter exhibits high transmission and significant blocking at the ranges of 170 Thz-205 Thz and 205 Thz-240 Thz, respectively. Furthermore, the designed all-pass filter possesses notable spectral transmissivity and blocking characteristics. The promising features of the structures were also verified via the finite-difference time-domain method. Such manufacturable optical filters with great device performances are favorable candidates for next-generation photonic applications.