| 1. |
- Girardi, Marcello, 1991, et al.
(författare)
-
3D Integration of Microcombs
- 2023
-
Ingår i: 2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023.
-
Konferensbidrag (refereegranskat)abstract
- Microcombs based on silicon nitride are a promising technology in applications such as sensing, metrology and telecommunication [1]. These applications often require to combine a nonlinear waveguide with a linear integrated processor on the same chip to perform functionalities such as splitting, demultiplexing, and optical buffering. However, there is a fundamental performance tradeoff between linear and nonlinear waveguides. For microcomb generation, thick waveguide cores are necessary to achieve the desired anomalous dispersion, while for linear operation a thin core improves the loss of a single mode (SM) waveguide [2]. The dissimilar requirements in waveguide thickness brings challenges for planar integrated technologies. Here, we propose and demonstrate wafer-level three-dimensional integration of microcombs using two different Si3N4 core thicknesses: a thick core featuring dispersion-engineered microcombs and a thinner core for linear processing (see Fig. 1a). This technology breaks off the fundamental tradeoff between loss and confinement in thick waveguides and opens the door to combine high-performance microcombs with ultra-low-loss silicon nitride waveguide technology [3]. We demonstrate this approach by efficiently coupling a microcomb between two layers of Si3N4 and demultiplexing a few lines with an arrayed waveguide grating (AWG) (Fig 1b).
|
|
| 2. |
- Girardi, Marcello, 1991, et al.
(författare)
-
Multilayer integration in silicon nitride: decoupling linear and nonlinear functionalities for ultralow loss photonic integrated systems
- 2023
-
Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 31:19, s. 31435-31446
-
Tidskriftsartikel (refereegranskat)abstract
- Silicon nitride is an excellent material platform for its extremely low loss in a large wavelength range, which makes it ideal for the linear processing of optical signals on a chip. Moreover, the Kerr nonlinearity and the lack of two-photon absorption in the near infrared enable efficient nonlinear optics, e.g., frequency comb generation. However, linear and nonlinear operations require distinct engineering of the waveguide core geometry, resulting in a tradeoff between optical loss and single-mode behavior, which hinders the development of high-performance, ultralow-loss linear processing blocks on a single layer. Here, we demonstrate a dual-layer photonic integration approach with two silicon-nitride platforms exhibiting ultralow optical losses, i.e., a few dB/m, and individually optimized to perform either nonlinear or linear processing tasks. We demonstrate the functionality of this approach by integrating a power-efficient microcomb with an arrayed waveguide grating demultiplexer to filter a few frequency comb lines in the same monolithically integrated chip. This approach can significantly improve the integration of linear and nonlinear optical elements on a chip and opens the way to the development of fully integrated processing of Kerr nonlinear sources.
|
|
| 3. |
- Twayana, Krishna Sundar, 1986, et al.
(författare)
-
Multi-Heterodyne Differential Phase Measurement of Microcombs
- 2023
-
Ingår i: 2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC). - 9798350345995 - 9798350345995
-
Konferensbidrag (refereegranskat)abstract
- Microcombs have been an intense area of research in frequency synthesis and metrology over the past decade. The measurement of amplitude and phase of microcombs provides unique insight into the nonlinear cavity dynamics. Different techniques have been reported to this aim, including iterative pulse shaping [1], dual-comb interferometry [2] and lately stepped-laser interferometry [3], resulting in unprecedented sensitivity and bandwidth. Here, we report a dramatic simplification of the latter setup by using another microcomb instead of a stepped tunable laser. This results into the acquisition of complex spectra in a single-scan without requiring additional optical components and high-end detection units.
|
|
