Fig. 5: Si-As2S3 MWP notch filter. | Nature Communications

Fig. 5: Si-As2S3 MWP notch filter.

From: Integrated microwave photonic notch filter using a heterogeneously integrated Brillouin and active-silicon photonic circuit

Fig. 5

a Experimental setup. b Measured RF notch filter response with the narrow 3-dB bandwdith of 37 MHz and large 51 dB rejection annotated. c Measured RF response of the MWP notch filter with a notch at 8 GHz. d Notch filter frequency tuning. The notch frequency is changed between 2.5–15 GHz. e Measured optical spectra for two different CSRs. Optical processing on the Si-As2S3 PIC reduces the CSR from CSR1 (blue) to CSR2 (orange). The modulated sideband is offset by 7 GHz from the optical carrier. f Measured RF response for notch filters with CSR1 and CSR2. g Measured notch and bandpass filter responses. A bandpass response can be created by changing the DC bias of the on-chip DDMZM, such that the photocurrents destructively interfere outside the Brillouin resonance. L Laser (Teraxion NLL), EDFA Erbium-doped fibre amplifier, PC Polarisation controller, C Circulator, TC Tunable coupler, VOA Variable optical attenuator, TPS Tunable phase shifter, DDMZM Dual-drive Mach-Zehnder modulator, BPF Band-pass filter (BPF1, BPF3: Santec OTF-320. BPF2: Alnair BVF-300CL).

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