Thermo-optical polymer ring resonator integrated with tunable directional coupler

Waveguide ring resonators are key elemental devices for wavelength filters, optical switches, lasers and optical sensors. In order to control the finesse and notch depth of the resonator, the coupling ratio needs to be varied widely and accurately. A novel thermooptic polymer ring resonator integrated with a tunable directional coupler was theoretical analyzed. Polymer materials with different thermooptic coefficients were chosen as the core and cladding layers of waveguides. The structure of the directional coupler was optimized to achieve large tuning range of coupling ratio. The finesse, notch depth and the resonant frequency peak of the resonator can be controlled precisely by temperature. The coupled-mode theory (CMD) and beam propagation method (BPM) were used to simulate the characteristics of the tunable directional coupler. The transmission spectra and loss characteristic of the resonator are also discussed in detail. This device can be used to improve the performance of integrated optical gyroscope (IOG) and other resonator-based photonic integrated circuits.