Search

The 2-μm-waveband has been recognized as a potential telecommunication window for next-generation low-loss, low-latency optical communication. Thermo-optic (TO) modulators and switches, which are essential building blocks in a large-scale integrated photonic circuit, and their performances directly affect the energy consumption and reconfiguration time of an on-chip photonic system. Previous TO modulation based on metallic heaters at 2-μm-waveband suffer from slow response time and high power consumption. In this paper, high-performance thermo-optical Mach–Zehnder interferometer and ring resonator modulators operating at 2-μm-waveband were demonstrated. By embedding a doped silicon (p++-p-p++) junction into the waveguide, our devices reached a record modulation efficiency of 0.17 nm/mW for Mach–Zehnder interferometer based modulator and its rise/fall time was 3.49 μs/3.46 μs which has been the fastest response time reported in a 2-μm-waveband TO devices so far. And a lowest Pπ power of 3.33 mW among reported 2-μm TO devices was achieved for a ring resonator-based modulator.

Slot waveguide has attracted a lot of attention due to its ability to confine light in the low refractive index region, while strip waveguide acts as the basic component of guiding light due to its relatively low optical loss. In the multifunctional photonic integrated chips, it is critical to achieve the low loss transition between the strip waveguide and the slot waveguide. In this work, a silicon nitride strip-slot mode converter with high efficiency, large bandwidth, and large fabrication tolerance are proposed and demonstrated through the numerical investigation and experiments. The coupling efficiency of the mode converter is up to - 0.1 dB (97.7%), which enables the extremely low transition loss between the strip waveguide and the slot waveguide. Moreover, the fabrication process of silicon nitride photonic devices with high performance is introduced, which is fully compatible with the CMOS technology. Photonic devices based on silicon nitride with the characteristics of the low optical loss and the temperature insensitivity represent a new paradigm in realizing silicon-based photonic multifunctional chips.

A ring resonator-based biochemistry sensor with a wide range, ultra-compact footprint, and high sensitivity is proposed, which utilizes a suspended slot hybrid plasmonic (SSHP) waveguide. The waveguide consists of a suspended Si nanowire separated from a Cu metal surface by a nanoscale air gap. The hybridization of fundamental mode of a Si channel waveguide with the surface plasmon polariton (SPP) mode of Cu-Si interface achieves a strong light confinement, high waveguide sensitivity (Sw), and low optical loss, showing a great potential in integrated optical sensor. The sensitivity, the detection limit and the detection range of the SSHP waveguide-based biochemistry sensor with a miniaturized radius of 1 µm are numerically demonstrated as 458.1 nm/RIU, 3.7 × 10−5 RIU and 0.225 RIU, respectively. These superior performances as well as the fully CMOS compatibility enable the integrated optical sensing applications.