Precision optical filters are key components for current and future photonic technologies. Here, we demonstrate a low loss spectral filter consisting of an ultrasteep bandpass feature with a maximum gradient of (90.6±0.7) dB/GHz, centred within a notch filter with (128±6) dB of suppression. The filter consists of a fiber Bragg grating with multiple π-phase discontinuities inscribed into a single mode photosensitive fiber. The measured performance closely matches the simulated spectrum calculated from the design parameters indicating a high degree of confidence in the repeatability and manufacture of such devices. These filters show great promise for applications reliant on high-frequency resolution noise suppression, such as quantum networking, and highlight the opportunities for the versatility, efficiency, and extreme suppression offered by high-performance fiber Bragg grating devices.
@article{arxiv.2412.00981,
title = {Efficient, ultra-high attenuation fiber Bragg grating filter for photon noise suppression},
author = {Benjamin R. Field and Chintan Mistry and Liguo Luo and Goran Edvell and Joss Bland-Hawthorn and Sergio Leon-Saval and John G. Bartholomew},
journal= {arXiv preprint arXiv:2412.00981},
year = {2024}
}