Integrated analogue–digital control circuit for photonic switch matrices

An analogue–digital circuit for thermal control of the resonance frequency of optical ring resonators is suggested. This approach is characterised by a low power dissipation of 209 µW and needs only 2800 µm2 of chip area in 0.16 µm CMOS technology. Therefore, it is well appropriate to be used to control each of the cells of large optical switch matrices. Compared with a purely analogue heater control approach the power dissipation is reduced to 7%.