A fully integrated 10-Gb/s tapped delay Hilbert transformer for optical single sideband

Integrated frequency comb source based Hilbert transformer for wideband microwave photonic phase analysis

“…The process of obtaining in-phase and quadrature-phase components of a signal can be achieved via a Hilbert transform, and for RF signals this is often achieved using a so-called 'hybrid coupler' [1]. While microwave hybrid coupler technology is very mature, the performance of these components is often degraded by large amplitude and phase ripple [2][3][4]. In addition, it is difficult to achieve wide band operation using electronic circuits.…”

RF and microwave photonic high bandwidth signal processing based on Kerr micro-comb sources

“…Fractional Hilbert transform (FHT) provides a variable phase shift for applications such as hardware keys [145,146], secure single sideband communications [145], and in forming an image that is edge enhanced relative to the input object, where they can select which edges are enhanced and the degree of edge enhancement [147]. Electronic fractional Hilbert transformers are limited in operation bandwidth [145,148], whereas photonic technologies offer broadbandoperation as well as strong immunity to EMI. Hilbert transformers based on free-space optics have been demonstrated [146,149] that achieve high performance but are bulky and complex.…”

RF and microwave photonic high bandwidth signal processing based on Kerr micro-comb sources

“…Fractional Hilbert transforms (FHTs) that yield a variable phase shift represent a powerful extension to the standard HT, with applications to secure single sideband communications [145], hardware keys [145,146], and in forming images that are edge enhanced relative to the input object, where one can select the edges that are enhanced as well as the degree of edge enhancement [147]. Electronic fractional Hilbert transformers are limited in operation bandwidth [145,148], whereas photonic technologies offer broadband operation as well as strong immunity to EMI. Hilbert transformers based on free-space optics have been demonstrated [146,149] that achieve high performance but are bulky and complex.…”