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Recently, electro-optic integrated photonic elements have attracted considerable interest owing to their widespread application in optical communication and signal processing. The strong electro-optical properties and the complementary metal–oxide semiconductor (CMOS) technology compatibility of silicon–organic hybrid structures makes them promising photonic platforms. This study investigated a novel implementation of a high-speed electrically tuned bandpass optical filter using finite-difference time-domain and eigenmode expansion numerical methods. The proposed device was based on a Fabry–Perot cavity and was realized via an electro-optic organic molecular glass filled slot waveguide with Bragg gratings. Furthermore, the calculation considered the plasma dispersion effect, free-carrier absorption in the silicon component of the slot waveguide for different applied voltages, and doping profiles corresponding to ion implantation. It is shown that the spatial distribution of charge carrier density formed by the surface states accumulation/depletion layers has a significant effect on the optical properties of the slot waveguide. Lithographic distortions in the geometry of the proposed structures during fabrication were also considered. Therefore, this paper presents an optical filter designed for fabrication using CMOS-compatible processes on silicon-on-insulator wafers. The filter produced a 3 nm tunable range for a 10 V bias voltage swing, a 0.3 nm full width at half maximum (FWHM) passband with a center at 1550 nm at zero bias voltage, and a 12.5 nm free spectral range with a 27 dB extinction ratio. The proposed device outperforms many narrow passband analogs in terms of sensitivity (tunability: 0.3 nm/V) and can be applied extensively in the fields of optical communications and photonic spectral signal processing. [ABSTRACT FROM AUTHOR]

Photonic Integrated Circuits (PICs) on indium phosphide have matured significantly over the past couple of decades and have found use in many system applications. Some PIC efforts on other group III-V substrates have also been initiated. In numerous cases, the usefulness of these PICs is because of the reduction in size, weight, and power they provide, but in many cases also because of the higher performance made possible by the improved relative phase stability among optical paths as well as the reduction of inter-element coupling losses. In this paper, as part of this special issue in tribute to Prof. Daniel Dapkus, we focus on monolithic PICs that provide a system function, especially those that incorporate and build on widely-tunable laser technology as a key element. Some of the early widely-tunable laser work is reviewed, and a selection of past system-on-a-chip developments is presented as background. Then, more recent system-on-a-chip advances performed by the author’s groups are reviewed in more detail. Key advances are highlighted. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate the design, fabrication, and performance estimation of an integrated Bragg grating (IBG) filter having stressed Si3N4 periodic layer over silicon waveguide. The influence of stress-optic effect on the optical performance of the proposed IBG filter is experimentally verified. The proposed IBG filter is fabricated with the different number of grating periods and therefore offers different spectral properties. The proposed filters are designed for a set of target specifications; such as center wavelength, bandwidth, and extinction ratio. The optical performances including temperature sensitivity of the filters are numerically estimated in the absence and presence of stress and are compared with fabricated filter characteristics. The study reveals that the filter, which is designed using numerical simulation considering stress effect, shows the similar optical performance to the fabricated IBG filter. It is also found that the increase of the number of grating periods increases the extinction ratio with narrowing of spectral bandwidth. The IBG filter experimentally demonstrates maximum temperature sensitivity and extinction ratio of 90 pm/°C and 26 dB respectively. The proposed IBG filter offers compact footprint and improved characteristics in comparison to the previously reported filters and finds its potential application in sensing and optical communication. Therefore, the presented work highlights the potency of stress-optic effect in enhancing the capabilities of photonic devices. [ABSTRACT FROM AUTHOR]

Supercontinuum generation has been extensively studied in optical waveguides pumped with femtosecond pulses, while there are few reports using picosecond pump pulses with a small spectral power variation. In this paper, we numerically demonstrate the supercontinuum generation in a dispersion-engineered silicon nitride waveguide pumped with 10-ps pulses at 1550 nm wavelength. A supercontinuum from 656 to 3867 nm (2.5 octaves) is enabled by uniquely tailored dispersion. The spectrum has a power variation of < 15 dB and shows a very flat pedestal varying by < 5 dB. The spectra generated from different dispersion profiles are compared and analyzed, which verifies the unique role of dispersion tailoring in flattened supercontinuum generation. To the best of our knowledge, it is the first study on such broad and flat supercontinuum generation on a chip using picosecond pump pulses, which would be highly desirable for many applications. [ABSTRACT FROM AUTHOR]