Table 1.

Comparison of reported programmable optical signal processor.

Year	Ref.	Material	Mesh structure	Size	Operation approach	Functionality
2015	20	Si3N4	Square	7 × 3.5 mm2	MZI coupler	-Notch filter -Hilbert transformer, -Bandpass filter, -Delay line
2016	39	III–V	Ring	1.5 × 2 mm2	Ring resonator	-Integrator -Differentiator -Hilbert transformer
2017	21	SOI	Hexagonal	15 × 20 mm2	MZI coupler	21 functionalitiesa
2019	Our work	SOI	Square	0.4 × 0.4 mm2	MDR	-Demultiplexer -Flat-top filter -Tunable delay line -Differentiator -Beamforming network -Optical pulse shaper

^a21 different functionalities include unbalanced FIR Mach–Zehnder filters, ring cavities, complex CROW, SCISSOR, and ring-loaded MZI filters, and multiple input–multiple output linear-optic transformation devices, including a C-NOT gate