Generating a Bessel beam by using a twisted integrated silicon photonic chip

The Bessel beam's propagation length is crucial for imaging applications. However, the length is challenging to further extend for the generation structure with a fixed conical angle. Here, we extended this result by rotating the sub-beams for the first time. Specifically, a crooked-headed photonic chip with an angle of 30 ° is designed, manufactured, and tested. The Bessel beam with 900 µm length is measured at the incident wavelength of 1528 nm. The path of beam synthesis is no longer the traditional conical surface but a single hyperbolic surface, which can prolong the overlap region. The experimental results bring a new scheme for the generation of a Bessel beam. In addition, we introduced the decentered Gaussian beam (DGb) model into the grating arrays or optical phased arrays (OPA) and demonstrated the transition from DGb to Bessel beam. The theoretical calculation results are consistent with the experimental results. The model accurately describes the beam steering and is expected to be applied in LiDARs based on grating arrays or OPA. Thanks to the silicon photonic chips' small footprint and mass production capability, our method can provide an on-chip solution for slight particle rotation, communication on-chip, and long-range sensing.