This application note is intended to demonstrate spectral tunability of a single-stage ring resonator that can be used as an integrated photonic add-drop multiplexer in multi-channel fiber-optic systems . Ring resonator is an important component in silicon photonics. It is made up of an optical waveguide in a loop fashion with coupling mechanism as shown in the schematic of Figure 1.
As per the theory of ring resonators , the ring is in resonance when wavelength of the light fits integer number of times in the optical length of the ring. The resonance wavelength is given by:
Where m is a non-zero positive integer, L is the optical roundtrip length of the ring, and neff is the effective index of the waveguide.
Free spectral range (FSR) is an important specification of a ring resonator. It is the spacing between resonances and is given by:
Figure 1. Layout of a single-stage ring resonator circuit with thermal tuning.
Figure 3. Thermally-tuned drop spectrum.
This application note demonstrated spectral tunability of a single-stage ring resonator that can be used as an integrated photonic, tunable add-drop multiplexer in multi-channel fiber-optic systems. Please contact us in case of questions or for more information on your modeling needs.