Spectral engineering with coupled microcavities: active control of resonant mode-splitting

Abstract

Optical mode-splitting is an efficient tool to shape and fine-tune the spectral response of resonant nanophotonic devices. The active control of mode-splitting, however, is either small or accompanied by undesired resonance-shifts, often much larger than the resonance splitting. We report a control mechanism that enables reconfigurable and widely tunable mode splitting while efficiently mitigating undesired resonance shifts. This is achieved by actively controlling the excitation of counter-traveling modes in coupled resonators. The transition from a large splitting (80 GHz) to a single-notch resonance is demonstrated using low-power microheaters (35 mW). We show that the spurious resonance shift in our device is only limited by thermal crosstalk, and resonance-shift-free splitting control may be achieved.

Advanced photonic filters based on cascaded Sagnac loop reflector resonators in silicon-on-insulator nanowires

“…The calculated power transmission spectra in Fig. 3(a) also indicate that the filter shape of the CSLR resonator can be tuned or optimized by introducing thermo-optic micro-heaters 19,33 or carrier-injection electrodes 39,40 along L 1,2 to tune the phase shift. Fig.…”

“…[10][11][12][13][14] Photonic resonators can be classified into two categories-travelling-wave (TW) resonators, exemplified by ring resonators, and standing-wave (SW) resonators represented by photonic crystal cavities, distributed feedback cavities, and Fabry-Pérot (FP) cavities. 3 The majority of work on mode splitting in photonic resonators has been based on TW resonators [15][16][17][18][19] although some recent work has investigated device structures consisting of both TW and SW resonators. [20][21][22] Since TW resonators are almost twice as long as their SW counterparts for the same FSR, 23 SW resonators tend to attract more interest in terms of device footprint.…”

Advanced Multi-Functional Integrated Photonic Filters Based on Coupled Sagnac Loop Reflectors

“…Clearly both the SR and the IL decrease with ts, reflecting the trade-off between them. Figure 3(c-ii) depicts the calculated SR and IL as functions of L. One can see that the resonant wavelength redshifts as L increases, indicating that it can be tuned by adjusting the phase shift with thermo-optic micro-heaters [37,39] or carrier-injection electrodes [44,45] along the connecting bus waveguides. In Fig.…”

Advanced Classical Optical Filters with Three Waveguide Coupled Sagnac Loop Reflectors

“…Resonance mode splitting is a fundamental phenomenon in photonic resonators that occurs when two or more mutually coupled modes co-exist in the same resonant cavity [140,141]. It can achieve a reduced free spectral range (FSR) and an increased quality (Q) factor while maintaining a small physical cavity length, thus yielding a compact device footprint, low power consumption, and versatile lter shapes for dense-wavelength division-multiplexing (DWDM) and microwave photonics applications [142,143].…”