2024/11/27 by Yating Wu, Wu, Yating, Tao Chu +1 · 1 citation
Engineering · Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Optical Network Technologies #Optics (physics.optics) #Photonic and Optical Devices #Semiconductor Quantum Structures and Devices
paper · pdf · doi:10.48550/arxiv.2411.18139
openalex publication_date 2024/11/27 · openalex created_date 2024/12/05 · openalex updated_date 2026/07/28
In silicon electro-optic (EO) Mach-Zehnder interferometer (MZI) switches, crosstalk is typically limited by beam imbalance between the MZI arms, primarily caused by the free carrier absorption loss during routing, thus hindering switch scalability. To address this issue, we propose a low-crosstalk push-pull EO MZI switch by cascading a lightly doped, long phase shifter (PSLL) and a heavily doped, short phase shifter (PSHS) to construct phase-shift arms. In both BAR and CROSS states, PSLL in one arm and PSHS in the other arm are simultaneously forward-biased, with PSLL provides a pi/2 greater phase shift for switching, while PSHS balances loss of PSLL, effectively minimizing crosstalk. Simulations indicate that the proposed switch achieves a crosstalk below -51 dB at a 1310 nm wavelength. The fabricated 2 x 2 silicon EO MZI switch exhibited crosstalk between -33 and -44.2 dB at 1316 nm, and maintained crosstalk below -30 dB across an impressive 61 nm optical bandwidth, with response times under 119 ns. Featuring single-pair electrode control, consistent two-state performance, and a compact size, this approach could enable high-radix switch fabrics in data centers and artificial intelligence compute clusters.