Previously reported double ring based reflectors use directly coupled rings. Moreover, precise fabrication of these gratings requires a high quality lithography process. The main problem with these approaches, though interesting results have been recently presented, is related to the footprint: indeed, a very high number of periods is needed to guarantee high reflection.
Other approaches for realizing single wavelength reflectors combine a Y-branch splitter with an embedded microring/microdisk or sidewall Bragg grating assisted ring and racetrack resonators. Coupled resonators could benefit of the vernier effect, which increases the wavelength tuning range (e.g. To tackle this issue, cascaded ring resonators have been proposed to enhance the FSR and pass band flatness without suffering from the reduced radius issues (see for more examples). Increasing the FSR to obtain a single working wavelength requires a reduction of the MRR radius, with an immediate fallout in an unacceptable increase of bending loss attenuation. A major drawback of these solutions is that they exhibit multiple reflected wavelengths, spaced according to the device overall FSR. For example, devices based on two rings or three and even more rings have been proposed. Resonator-based reflectors can be implemented by using many different configurations. Mirrors realized by MRRs have been previously proposed in literature for various applications such as laser cavities and sensing, as well as reflective filters in wavelength division multiplexing (WDM) systems.
In this paper we propose the use of micro ring resonators (MRRs) for the realization of tunable integrated mirrors with good performance: single wavelength, high reflectivity, large free spectral range (FSR) and narrow bandwidth. In the recent years, high index contrast integration platforms made the fabrication of small footprint photonic devices possible among them silicon-on-insulator (SOI) technology, attracting for its compatibility with CMOS devices, is of particular interest. Ring resonators can be fabricated with different integration technologies. They are attracting and versatile components, particularly suitable for many applications ranging from wavelength channel filters to laser cavities, modulators, routers or switches. Optical ring resonators have been first proposed by Marcatili in 1969, to investigate propagation losses in waveguide bends. © 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement 1. The proposed device can offer an alternative approach to realize compact reflective structures for single wavelength reflection operations in photonic integrated circuits. The average measured reflectivity over a wavelength span of 37 nm is 0.55, with a peak of about 50 pm full-width-half-maximum, which corresponds to a quality factor of ∼30, 000. The experimental results show a good agreement with the model outcomes. With the proposed configuration, by electrically driving the integrated micro heaters, a single reflection wavelength with narrow bandwidth can be tuned. The device is studied using an analytical model based on the transfer matrix method. This paper presents a novel narrow band wavelength selective optical reflector implemented by indirectly coupling two micro ring resonators in silicon-on-insulator technology. Note: Author names will be searched in the keywords field, also, but that may find papers where the person is mentioned, rather than papers they authored.Use a comma to separate multiple people: J Smith, RL Jones, Macarthur.Use these formats for best results: Smith or J Smith.For best results, use the separate Authors field to search for author names.