Design and Fabrication of Grating Couplers for the Optical Addressing of Trapped Ions

Abstract

In this work, silicon photonics structures for the optical addressing of trapped ion is developed for quantum computing applications. Grating-waveguide-grating structures of various designs are designed, and fabricated for various radius curvatures of 12, 15, 25 and 30 µm, respectively. From the optical measurements, gratings with radius of curvature of 25 and 30 µm exhibit lower power loss of 36.5 and 33.9 dB with better-focused beam profiles as compared to those with radius of curvature of 12 and 15 µm. The beam width from these gratings ranges between 17.31 to 41.54 µm, which provides the feasibility to perform optical addressing on 2 to 4 Sr + ions trapped along the ground electrode of the ion trap.

Development of Mixed Pitch Grating for the Optical Addressing of Trapped Sr+ Ion with Data Analysis Techniques

“…6(c) and (d), the beam waist along y-axis do not show significant difference between fixed pitch grating and mixed pitch gratings. As the beam waist along y-axis mainly depend on the taper shape and the radius of curvature [25], mixing the pitch in the grating shall not have direct influence towards the beam waist along y-axis. Whereas for beam waist along x-axis, it is observed that 6(1.2µm), 5(1.2µm), and 4(1.2µm) mixed pitch gratings show lower beam waists (Fig.…”

High efficiency focusing double-etched SiN grating coupler for trapped ion qubit manipulation

“…[20][21][22] Furthermore, integrated photonic control with 2D focusing surface grating couplers (GCs) has been used to diffract guided light from the chip to the ions captured in free space. [23][24][25] Full coherent control of a single trapped ion qubit has since been reported; a chip with four GCs designed for four wavelengths demonstrated fully integrated ion trapping, laser cooling, qubit initialization, and state control. 26,27) However, for multi-qubit control, tightly focused irradiation is needed for ions in a tightly packed chain.…”

Development of Grating for the Optical Addressing of Sr+ Ions With Data Analysis Techniques

“…Thus, in our previous work, we reported the investigation on the focusing of grating coupler with various radius of curvatures (r) on Silicon-On-Insulator (SOI) platform. Beam focusing along the out-of-plane axis has been observed [8]. However, the focusing was demonstrated on 1630 nm wavelength on silicon-on-insulator (SOI) platform, which is not applicable for optical addressing of trapped ions.…”

“…It has been reported that SOI platform is suitable for silicon photonics at near-to mid-infrared (NIR and MIR) range, due to the high transmissivity of silicon for NIR to MIR light (∼1200 nm onwards) [9]. Thus, the SOI is selected for grating design under 1630 nm wavelength in our previous study [8]. In the case of 1092 nm, SiN platform is selected due to the high transmissivity of SiN for visible and NIR range, which covers the wavelength-of-interest in this study [10].…”