We present a four channel optical add-drop multiplexer based on vertically coupled microring resonators fabricated in Si3N4/SiO2. The device with a Manhattan-like geometry has a footprint of 0.25 mm2 and can find application in metro-networks. The individual micro-resonators have a 50 μm radius and are thermally tunable over a 4 nm range. The maximum power consumption per ring is 0.5 W. Measurements show that each microring has a bandwidth >10 Gbit and can be thermally tuned in less than 1 ms. The measured on-off resonance in the drop ports of each micro-resonator is 10 dB