Design and measurement of a second-order silicon photonic CROW filter for self-coherent detection

We propose and verify a second-order coupled resonator optical waveguide (CROW) filter with a narrow 10dB bandwidth of 1.725 GHz and an extinction ratio of ~50 dB on the silicon photonic platform. The use of the narrow bandwidth CROW filter is further demonstrated in a self-coherent receiver system, by which only the optical carrier is filtered through while the signal is effectively suppressed by properly tuning the central wavelength of the CROW filter. Experimental results confirm the effectiveness of our design, showcasing its potential for enhancing the performance of self-coherent detection.