Optical isolation using microring modulators

Optical isolators, while commonplace in bulk and fiber optical systems, remain a key missing component in integrated photonics. Isolation using magneto-optic materials has been difficult to integrate into complementary metal-oxide- semiconductor (CMOS) fabrication platforms, motivating the use of other paths to effective non-reciprocity such as temporal modulation. We demonstrate a non-reciprocal element comprising a pair of microring modulators and a microring phase shifter in an active silicon photonic process, which, in combination with standard bandpass filters, yields an isolator on-chip. Isolation up to 13 dB is measured with a 3 dB bandwidth of 2 GHz and insertion loss of 18 dB. We also show transmission of a 4 Gbps optical data signal through the isolator while retaining a wide-open eye diagram. This compact design, in combination with increased modulation efficiency, could enable modulator-based isolators to become a standard 'black-box' component in integrated photonics CMOS foundry platform component libraries. (C) 2021 Optical Society of America

Automated summary

The study demonstrates a non-reciprocal element made up of a pair of microring modulators and a microring phase shifter in an active silicon photonic process, achieving an on-chip isolator. Isolation of up to 13 dB was achieved with an insertion loss of 18 dB. The design, along with increased modulation efficiency, could potentially make modulator-based isolators a standard 'black-box' component in integrated photonics CMOS foundry platform component libraries.