Silisyum fotonik tümleşik devrelerde kıvrımlı halka yansıtıcıları ve çınlaçları: Tasarım, üretim, ve inceleme

Meandering Loop Mirrors (MLMs) and resonators based on MLMs are designed, fabricated, and analyzed using silicon integrated photonics circuit (Si-PIC) technology for operation in the standard near-infrared (near-IR) telecommunication band. Optical waveguides, directional couplers (DCs), MLMs, meandering resonators (MRs), antisymmetric meandering resonators (AMRs), and symmetric meandering resonators (SMRs) with symmetric and antisymmetric DCs were designed, fabricated, and analyzed as a function of the DC length to scan the desired near IR telecommunication band. A silicon on insulator (SOI) platform is used to realize strip waveguides in transverse electric (TE) mode polarized single mode configuration. The structures' design is based on numerical simulations using a photonics design kit and resulting geometry of the structures were incorporated into the photonics layout for fabrication by e-beam lithography. After the writing of the silicon strip waveguide, and before oxide deposition, the photonic structures were imaged with scanning electron microscopy (SEM) to physically characterize the fabricated devices. Surface gratings are used to couple in and out of these photonic structures with single mode optical fibers. The excitation source for the spectral measurement of the device transmission is a tunable laser operating in the 1500 – 1600 nm wavelength range. The transmission signals in logarithmic (dB) scale are detected in the same experimental region using calibrated near-IR photodetectors. The data is acquired by a control and data acquisition computer. The experimentally measured transmission spectra are compared with the numerically simulated transmission spectra. The normalized linear scale is used to make the peaks more prominent, whereas the logarithmic (dB) scale is used to make the dips more prominent. To make the results more reader friendly, the spectra are color coded: the normalized transmission intensity (excluding grating couplers) are plotted in brown, the transmission intensity in logarithmic (dB) scale (excluding grating couplers) are plotted in red, the transmission intensity logarithmic (dB) scale (including grating couplers) are plotted in blue, whereas the transmission intensity (including grating couplers) are plotted in green. The free spectral range (FSR), finesse (F), quality factor (Q factor), and extinction ratio (ER) are deduced from both the experimentally measured, and the numerically simulated transmission spectra, and were found to be in good agreement. To understand the actual spectral response, we first analyze the simulated spectra, for the device under test. Since the input and outputs of the devices had to be connected to the grating couplers, to couple in and out from the optical fibers, the measurement responses are always modulated by the grating coupler responses, and thus cannot be directly compared to the numerical simulations. To make our simulation spectra comparable to the measurement spectra, we also simulated the transmission spectra of the devices including the grating couplers. First we analyze the wavelength dependence of a DC, one of the basic elements used in our designs. We look at the coupled and the transmitted port intensities, and compare them with the measurement results. Then we look at the MLM spectral response, which incorporates a DC. After developing the understanding of DC and the MLM, we move to the analysis of the spectral responses of more complex structures, e.g., MR, AMR, SMR. The general response of a tunable mirror is observed for the MLMs. MRs show the typical Fabry Pérot response. The AMRs show the typical spectra similar to the coupled resonator induced transparency (CRIT), the analogue of the electromagnetically induced transparency (EIT) spectral responses. Whereas the SMRs show the Rabi split Fano resonance spectral responses. All in all, MLMs and resonators based on MLMs show promise as a novel integrated photonics platform for Si-PIC elements for optical communication, computation, and sensing.