Photonic mesh rejects wavelengths with up to 40dB contrast

Researchers at Stanford University have created an integrated photonic circuit capable of rejecting wavelengths with contrasts reaching 40 dB. The work demonstrates a programmable filter built from a N = 4 input triangular mesh with M = 3 layers that can be operated to filter M arbitrary wavelengths from an input spectrum. Unlike conventional filters, this architecture enables preconfigured functions to sweep continuously across its spectral range, removing fixed wavelength limitations. The device offers potential improvements for applications including wavelength division demultiplexing, Raman spectroscopy, and correlation spectroscopy. Carson G. Valdez, of Stanford University's Ginzton Laboratory, and colleagues demonstrate this through a power splitting subcircuit implemented via…