Publications

2017
Compact narrow-linewidth integrated laser based on a low-loss silicon nitride ring resonator
Stern, Brian, Xingchen Ji, Avik Dutt, and Michal Lipson. “Compact narrow-linewidth integrated laser based on a low-loss silicon nitride ring resonator.” Optics Letters 42, no. 21 (2017): 4541-4544. Publisher's Version Abstract
We design and demonstrate a compact, narrow-linewidth integrated laser based on low-loss silicon nitride waveguides coupled to a III-V gain chip. By using a highly confined optical mode, we simultaneously achieve compact bends and ultra-low loss. We leverage the narrowband backreflection of a high-Q microring resonator to act as a cavity output mirror, a single-mode filter, and a propagation delay all in one. This configuration allows the ring to provide feedback and obtain a laser linewidth of 13 kHz with 1.7 mW output power around 1550 nm. This demonstration realizes a compact sub-millimeter silicon nitride laser cavity with a narrow linewidth.
compact_narrow_linewidth_laser.pdf
Wang, Cheng, Mian Zhang, Brian Stern, Michal Lipson, and Marko Loncar. “Nanophotonic Lithium Niobate Electro-optic Modulators.” arXiv 1701.06470 (2017). Publisher's Version Abstract
Modern communication networks require high performance and scalable electro-optic modulators that convert electrical signals to optical signals at high speed. Existing lithium niobate modulators have excellent performance but are bulky and prohibitively expensive to scale up. Here we demonstrate scalable and high-performance nanophotonic electro-optic modulators made of single-crystalline lithium niobate microring resonators and micro-Mach-Zehnder interferometers. We show a half-wave electro-optic modulation efficiency of 1.8V-cm and data rates up to 40 Gbps.
2015
Stern, Brian, Xiaoliang Zhu, Christine P. Chen, Lawrence D. Tzuang, Jaime Cardenas, Keren Bergman, and Michal Lipson. “On-chip mode-division multiplexing switch.” Optica 2, no. 6 (2015): 530-535. Abstract
Leveraging the spatial modes of multimode waveguides using mode-division multiplexing on an integrated photonic chip allows unprecedented scaling of bandwidth density for on-chip communication. Switching channels between waveguides is critical for future scalable optical networks, but its implementation in multimode waveguides must address how to simultaneously control modes with vastly different optical properties. Here we present a platform for switching signals between multimode waveguides based on individually processing the spatial mode channels using single-mode elements. Using this wavelength-division multiplexing-compatible platform, we demonstrate a 1×2 multimode switch for a silicon chip that routes four data channels with low (<−16.8  dB) crosstalk. We show bit-error rates below 10−9 and power penalties below 1.4 dB on all channels while routing 10 Gb/s data when each channel is input and routed separately. The switch exhibits an additional power penalty of less than 2.4 dB when all four channels are simultaneously routed. These results enable individual processing of multimode signals and high-bandwidth, flexible optical networks.
on-chip_mode-division_multiplexing_switch.pdf