Silicon nitride Si 3 N 4-on-SiO 2 attracts increasing interest in integrated photonics owing to its low propagation loss and wide transparency window, extending from ∼400 nm to 2350 nm. Scalable integration of active devices such as amplifiers and lasers on the Si 3 N 4 platform will enable applications requiring optical gain and a muchneeded alternative to hybrid integration, which suffers from high cost and lack of high-volume manufacturability. We demonstrate a high-gain optical amplifier in Al 2 O 3 :Er 3 monolithically integrated on the Si 3 N 4 platform using a double photonic layer approach. The device exhibits a net Si 3 N 4-to-Si 3 N 4 gain of 18.1 0.9 dB at 1532 nm, and a broadband gain operation over 70 nm covering wavelengths in the S-, C-and L-bands. This work shows that rare-earth-ion-doped materials and in particular, rare-earth-ion-doped Al 2 O 3 , can provide very high net amplification for the Si 3 N 4 platform, paving the way to the development of different active devices monolithically integrated in this passive platform.
A low-loss and broadband multimode interference (MMI)-based wavelength multi/demultiplexer in Si 3 N 4 /SiO 2 technology for erbium-doped lasing and amplifying applications is presented. The structural parameters of a 2 × 1 Si 3 N 4 MMI multi/demultiplexer are optimized to minimize losses. The design and analysis of the MMI multi/demultiplexer are carried out using a hybrid approach, which combines a modified effective index method, the 2D film mode matching method, and the 2D beam propagation method, with lower impact in the computing requirements and simulation time than 3D methods. Simulated total losses of 0.19 and 0.23 dB at 980 and 1550 nm, respectively were obtained for the optimized MMI multi/demultiplexer. The measurements of our fabricated couplers, with 110 nm thick Si 3 N 4 layer, show good agreement with our design. As multiplexers, the average losses of the MMI were measured to be 0.4 ± 0.3 dB for both 976 and 1550 nm wavelengths, and less than 1 dB across the whole C-band. As demultiplexers, the measured average extinction ratio of the fabricated MMI was found to be 21.4 ± 1.2 and 26.3 ± 0.8 dB for pump and signal wavelengths, respectively. Index Terms-Beam propagation and laser couplers, integrated optoelectronics, multi/demultiplexer, multimode interference (MMI), silicon nitride (Si 3 N 4 ).
Low-cost, high-performance integration technologies are instrumental for active-passive integrated photonics devices. The monolithic integration of Al 2 O 3 and Si 3 N 4 is studied, enabling to combine the promising optical features of Si 3 N 4 with the excellent optical gain characteristics of rare-earth-ion doped Al 2 O 3 . The Al 2 O 3 and Si 3 N 4 layers are separated by a thin SiO 2 film and coupled by adiabatically width-tapered Al 2 O 3 and thickness-tapered Si 3 N 4 waveguides. In this paper, a detailed characterization of the couplers, as well as a study of the influence of the different design parameters and fabrication tolerances on the final device performance is presented. Test structures are characterized under transverse electric (TE) polarization. Measured loss per coupler is as low as 0.26 ± 0.03 dB at the wavelength of 1030 nm, and below 0.24 dB in the spectral window of 1460-1635 nm. Lateral misalignment of ±1 µm results in less than 0.6 dB increase of the coupler loss at 1030 nm, and the tolerance of misalignment goes up to 1.7 µm at the investigated longest wavelength of 1635 nm without introducing extra coupler losses. The reported integration technology paves the way toward a double-layer platform monolithically integrating Si 3 N 4 and rare-earth-ion doped Al 2 O 3 for active-passive photonic functionalities.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.