摘要： Energy-ef?cient communication links are crucial for future processors and optoelectronic microchips in order to continue growths in computing and information technologies [1]. Wavelength-division multiplexing (WDM) techniques based on silicon photonic circuits are ideal for high bandwidths data communication systems with small footprints [2,3]. Compact double ring resonators (DRRs) provide excellent properties to realize spectral ?lters with ?at-top transmission characteristics, providing a steep roll-off with low channel crosstalk at dense frequency grids. Hence, cascaded DRRs as illustrated in Fig. 1 (a) are well-suited for integrated WDM systems on optoelectronic microchips. The high refractive index of silicon facilitates small ring perimeters and the wide free spectral range (FSR ∝ 1 Lr ) enables multiplexing tens of data channels to a common bus waveguide. The high energy-ef?ciency which is enhanced by the strong thermo-optic effect (TOE) combined with the short physical lengths is another relevant advantage of the compact size. However, manufacturing variability and associated photonic component deviations remain a serious drawback [4]. Hence, most recent works use thermal heaters for the dynamic ?lter control as well as to counterbalance inevitable manufacturing deviations [5-7]. In this work, we present multilayer compatible 5 and 10μm radius DRR ?lters based on microrings manufactured with deposited amorphous silicon [8]. We demonstrate a permanent correction of manufacturing variations and optimize the spectral properties of DRR ?lters. Such fabrication imperfections which may arise more frequently in multilayer circuits are exempli?ed in Fig. 1 (a) where widths (Δw), heights (Δh), and refractive index (Δn) variations are implemented to one microring; even lowest deviations substantially degrade the ?lter response. A DRR measurement with undesired drop port splitting which was corrected through the SiO2 top cladding by 405 nm laser-trimming one of the rings is shown in Fig. 1 (b); the intermediate trimming spectra are provided in order to guide the eye. The possibility to permanently align ?lters to a given wavelength channel is presented in Fig. 1 (c). In this experiment both 5 μm radius racetracks were alternately trimmed to shorter wavelengths, without degrading the spectrum or the ?lter bandwidths. In summary, several compact DRR ?lters with multiplexers up to 8-channels suitable for multilayer integration at the CMOS back-end-of-line with start-of-art performance were successfully fabricated and tested. Malfunctioning components were identi?ed and optimized on micron-scales by a post-fabrication trimming method. The proposed correction method for DRR multiplexers allows adjusting ?lters to a prespeci?ed wavelength channel and enables more generalized concepts which do not require a thermal heater for each ring thereby mitigating detrimental thermal crosstalk and lowering the overall energy consumption.