Thermally actuated optoelectronic switch array for wavelength modulation/lock within 0.01-nm fluctuation

Thermal actuated optoelectronic ring switch provides the advantages of high accuracy, easy actuation, and reasonable switching speed. However, when scaled up, the thermal ring switch may encounter issues related to fabrication error, nonaccurate wavelength response, and large terminal numbers in the control circuit. We propose the employment of an integrated control circuit to compensate for the fabrication error and tune as well as lock the wavelength in a thermal-actuated ring-type optical switch through an amplitude modulation scheme. Additional functionalities can also be added in this circuit by externally tailoring the round-trip loss or coupling constants of the ring. The design concept can be easily scaled up for large array optical switch system without much change in the terminal numbers thanks to the three-dimensional hierarchy of high gray-scale control circuit design, which effectively reduces the terminal numbers into the cubic root of the total control unit numbers. The integrated circuit has been designed, simulated, as well as fabricated, and demonstrated a decent performance with free spectral range equal to 1.5nm at 1534nm and very accurate wavelength modulation to 0.3nm within 0.01nm fluctuation for the thermal actuated ring-type optical switch.