Suspended Silicon Waveguide with Sub-Wavelength Grating Cladding for Optical MEMS in Mid-Infrared

Abstract

Mid-infrared (MIR) photonics are generating considerable interest because of the potential applications in spectroscopic sensing, thermal imaging, and remote sensing. Silicon photonics is believed to be a promising solution to realize MIR photonic integrated circuits (PICs). The past decade has seen a huge growth in MIR PIC building blocks. However, there is still a need for the development of MIR reconfigurable photonics to enable powerful on-chip optical systems and new functionalities. In this paper, we present an MIR (3.7~4.1 μm wavelength range) MEMS reconfiguration approach using the suspended silicon waveguide platform on the silicon-on-insulator. With the sub-wavelength grating claddings, the photonic waveguide can be well integrated with the MEMS actuator, thus offering low-loss, energy-efficient, and effective reconfiguration. We present a simulation study on the waveguide design and depict the MEMS-integration approach. Moreover, we experimentally report the suspended waveguide with propagation loss (−2.9 dB/cm) and bending loss (−0.076 dB each). The suspended waveguide coupler is experimentally investigated. In addition, we validate the proposed optical MEMS approach using a reconfigurable ring resonator design. In conclusion, we experimentally demonstrate the proposed waveguide platform’s capability for MIR MEMS-reconfigurable photonics, which empowers the MIR on-chip optical systems for various applications.

Multispectral transmission through phoxonic crystal slot-waveguide at midwave infrared frequencies

“…For comparison, the most relevant and recent works related to the conventional waveguide architectures belonging to different technology platforms were chosen. It can be observed that one of the popular approaches i.e., suspending 33 the core from the bulk results in considerable reduction of the bulk scattering losses. However, such a reduction has only been observed either at single or dual wavelength peaks (6.4 or 8.5) μm with approximate bandwidth up to 3 μm, using conventional waveguide architectures viz., Rib 48 and Ridge 31 type.…”

“…Such a possibility of high mode confinement within small volumes anticipates an ultra-strong nonlinear interaction for the purpose of the novel cavity-optomechanical (C-OM) devices and applications. Recently, technology platforms like silicon on insulator (SOI), 29 germanium on insulator (GOI), 14 indium phosphide (InP), 30 and Ge-rich SiGe 10 , 11 , 15 , 31 (silicon–germanium) with waveguide topologies like rib/ridge, 32 suspended, 33 , 34 and self-collimated virtual PxC have theoretically as well as experimentally, shown considerable improvement in the direction of achieving low-loss, multispectral on-chip MWIR transmission. Despite the flexibility that these waveguide platforms offer, the mandatory condition to have high refractive index contrast between core and cladding limits them to have minimum propagation losses at one or two wavelength peaks.…”

Downsizing Effects on Micro and Nano Comb Drives

“…This enduring trend [2], together with the consequent evolution of massive low-cost and large-scale semiconductor and microelectronics technologies [3], also triggered the conception and manufacturing of micromechanical structures [4], paving the way to the birth and growth of Micro Electro-Mechanical Systems (MEMS) [5][6][7][8]. MEMS can be used as extremely miniaturized sensors, actuators, microgrippers [9][10][11], with different sorts of actuation [12][13][14], piezoelectric resonators [15,16], and wave-guides [17], to only name but a few. They share with microelectronic devices the same conceptual platform: processes, technologies, and facilities able to produce low-cost, large-volume fabrication steps [18,19].…”

Larger-Than-Unity External Optical Field Confinement Enabled by Metamaterial-Assisted Comb Waveguide for Ultrasensitive Long-Wave Infrared Gas Spectroscopy

“…A 150 nm wide Si wire is added in the middle of the comb structure to avoid the adhesion between adjacent free-standing beams. The grating period is chosen to satisfy the subwavelength condition, that is, Λ ≪ λ/(2 n eff ), where n eff is the waveguide mode effective index. , At the overlap region, the period is reduced to Λ/2, making our waveguide work in the deep-subwavelength regime, where reflection and diffraction effects are significantly suppressed. We define the duty cycle of ADMAC waveguide as W s /Λ, where W s is the width of the Si beam (Figure b).…”