Design of narrow band photonic filter with compact MEMS for tunable resonant wavelength ranging 100 nm

Abstract

A prototype of planar silicon photonic structure is designed and simulated to provide narrow resonant line-width (∼2 nm) in a wide photonic band gap (∼210 nm) with broad tunable resonant wavelength range (∼100 nm) around the optical communication wavelength 1550 nm. This prototype is based on the combination of two modified basic photonic structures, i.e. a split tapered photonic crystal micro-cavity embedded in a photonic wire waveguide, and a slot waveguide with narrowed slabs. This prototype is then further integrated with a MEMS (microelectromechanical systems) based electrostatic comb actuator to achieve “coarse tune” and “fine tune” at the same time for wide range and narrow-band filtering and modulating. It also provides a wide range tunability to achieve the designed resonance even fabrication imperfection occurs

Design of curved photonic cavities for a narrow-band widely tunable resonance ranging 200 nm

“…In this paper, we show that a very wide tuning range of up to 200 nm (which is twice as wide as ever reported previously for such a sharp resonance [9]) by proposing a new type of photonic resonator suspended in air, namely a "tunable curved resonator (TCR)". To construct the TCR, a straight photonic resonator is curved at the cavity part and divided into two parts with one of them driven by a MEMS electrostatic comb actuator, providing the ability of tuning the length of a resonant cavity made of solid materials for efficiently tuning its resonant wavelength, which is not possible with straight cavities as discussed firstly in the paper.…”

“…When integrating such devices in photonic circuits, on-chip reconfiguration of the devices for programmable modulation of light is desirable. Recently widely and continuously tunable resonances ranging 10 to 100 nm have become an interesting research direction through the design of compact reconfigurable micro/nano photonic structures integrated with MEMS [6][7][8][9]. These designs are usually silicon photonic crystal based structures suspended in air.…”

“…Due to the high refractive index contrast between the silicon waveguide to the air holes, the width of the photonic band gap can be more than 300 nm centered at the optical communication wavelength 1550 nm with a proper design geometry [10]. Though a tunable range for the resonance of up to 100 nm has been shown possible in our previous work [9], itself already 20 times wider than that achievable by carrier injection [11,12] and 5 to 10 times wider than that of any other reported MEMS electrostatic tuning designs [6][7][8], there is still available wavelength range within the photonic band gap to accommodate a wide (> 100 nm) tuning range for the narrow-band resonance, which would provide a wider range of signal channel selection for tunable optical filters, switches and photonic crystal lasers. In our previous design [9] employing a straight split photonic crystal resonator with a nano-meter wide air gap throughout the structure, the tuning range of resonance with narrow band width and high transmission could only achieve 100 nm, which is limited by the change of effective refractive index as the air gap becomes wider and wider in the course of modulation.…”

Recent Progress in Silicon‐Based Photonic Integrated Circuits and Emerging Applications

“…PhC filters are suitable basic units for PICs for their flexible structure and excellent performance. [235][236][237] 2D PhC-based microring resonators also have the advantages of 2D PhC and microring resonators, which have very well optical confinement and small footprint size. A PhC-based ring resonator of the hexagonal lattice was proposed by Hsiao and Lee as shown in Figure 4g.…”

Development Trends and Perspectives of Future Sensors and MEMS/NEMS

“…A great number of impressive sensors were made with those technologies in the process of mass production. However, many critical issues in MEMS/NEMS fabrication still need to overcome, such as bulk etching, wire bonding, wafer-level packaging, and complex lithography [25][26][27][28]. To solve the conventional MEMS technology in the bulk etching with a rough surface, Figure 2a reports a typical MEMS fabrication using both potassium hydroxide (KOH) and Isopropyl alcohol (IPA) solution.…”