Electro-optic tuning and modulation of single-crystalline organic microring resonators

We present, for the first time to our knowledge, the fabrication and electro-optic (EO) tuning of single-crystalline organic microring resonators. In recent years, optical microring resonators have proven to be highly suitable building blocks for the realization of very large-scale integrated photonic circuits. In particular, microresonators based on organic materials are very promising for ultrafast EO applications, due to the electronic nature of the EO response preserving the modulation performances beyond 100 GHz. In contrast to polymer waveguiding structures realized previously, our crystalline thin-film devices feature an excellent long-term stability of the chromophore orientation and superior photochemical stability, and they do not require high-field poling prior to operation. The introduced thin-film fabrication method significantly reduces fabrication complexity of organic crystalline EO waveguides, compared to previously developed techniques. We have fabricated crystalline COANP (2-cyclo-octylamino-5-nitropyridine) microring resonators with resonance contrast up to 10 dB, ring waveguide propagation losses of about 10 dB/cm, a free spectral range of 1.6 nm, a finesse of up to 20, and a corresponding Q-factor of about 20,000, measured in the telecom wavelength range around 1.55 mu m. We have demonstrated resonance wavelength tuning at the rate of 0.13 GHz/V (1.1 pm/V). (C) 2009 Optical Society of America