Parallel emitted silicon nitride nanophotonic phased arrays for two-dimensional beam steering

Abstract

In this Letter, a two-dimensional (2D) beam steering on silicon nitride (SiNx) nanophotonic phased arrays from visible to near-infrared wavelengths is reported for the first time, to the best of our knowledge. In order to implement beam steering along the transverse direction for one-dimensional waveguide surface grating arrays, wavelengths from 650 to 980 nm provided by the supercontinuum laser are used to excite the phased array. Then the beams are parallel radiated with steering angles in a sequence of 26.84° to − 16.54 ∘ along the transverse direction, and a continuous line in the far field consisting of parallel emitted spots is produced with a total view angle of 43.38°. Moreover, this continuous far-field line is steered along the longitudinal direction with massive wavelengths simultaneously tuned by phase shifts from − π / 2 to over + π / 2 . This method with massive parallel wavelengths emitted paves a new way for 2D steering on SiNx nanophotonic phased arrays.

Enhanced coupling efficiency of optical fiber to green light waveguide by optical phased array

“…, where 𝐸 𝑓𝑖𝑏𝑒𝑟 (𝑥, 𝑦) and 𝐸 𝑤𝑎𝑣𝑒𝑔𝑢𝑖𝑑𝑒 (𝑥, 𝑦) are the mode field distribution of fiber and waveguide separately [7], thus the theoretical coupling efficiency is calculated to be 0.0619 (-12.8dB) contributed by the mode field overlap, which is comparatively low than that of fiber chip coupling in the nearinfra wavelength [6,9,10]. For measuring the loss of designed waveguide of blue-green light phased array, the experimental setup in fig.…”

“…Practical implementations of the blue-green light phased array for above applications requires highefficiency coupling to ensure the OPA chip to get enough emitting energy [5]. The traditional fiberwaveguide couplers can be divided to two categories, grating couplers and edge couplers [6][7][8][9][10]. The alignment tolerance of grating couplers is large but the bandwidth is limited.…”

Design a common optical path system for near- and far-field detection of optical phased array chips

“…In recent years, there have been significant advancements in integrated photonics chips for free-space optical communication, especially in the field of optical phased array (OPA), which exhibits immense potential for applications in light detection and ranging (LiDAR) 1 . After the chips are fabricated, researchers typically employ Fourier optical systems, 2 – 10 mechanical spatial scanning systems, 11 – 13 and hybrid detection systems combined with precision mechanical structures 14 – 16 to achieve near- and far-field detection of OPA chips. Calibration and phase modulator characterization can be accomplished through near- and far-field measurements on the OPA chips.…”

“…When using a Fourier optical system to detect the near- and far-field of an OPA chip, a set of lenses needs to be added or removed to switch between near-field and far-field detection modes, 2 – 10 which is tedious for researchers during practical testing. In Refs.…”

Microcantilever-integrated photonic circuits for broadband laser beam scanning

“…Another major obstacle is that the half-wavelength pitch criterion for single-lobe emission in an OPA 15 is hard to satisfy in the visible spectrum without introducing significant inter-waveguide crosstalk or reducing the minimum feature size. Recent demonstrations of visible-light beam scanners have been based on OPAs 28 – 33 using an external super-continuum source coupled with a tunable filter 33 or a rotation stage to scan the beam in the second dimension while requiring high on-chip driving powers of 2 W 31 . These approaches are difficult to miniaturize into single chips in the foreseeable future.…”