Reflection-insensitive semiconductor laser integrated with a non-magnetic optical isolator

The proposed research aims to develop a chip-scale narrow-linewidth laser at 778.1nm that is fully integrated with a non-magnetic optical isolator on the same chip, for applications in optical clock technologies. The proposed research is based upon novel self-injection-locked frequency-conversion laser technology recently developed by our team, which can produce ultra-narrow-linewidth high-power high-coherence lightwave in the visible and near-infrared (NIR) spectral regions, with laser wavelength by design of nonlinear photonic integrated circuit (PIC).  The proposed laser-chip system will be realized via hybrid integration and packaging between an InP distributed-feedback (DFB) laser chip and a thin-film lithium niobate (TFLN) PIC chip. Development will leverage our team’s world-leading expertise in TFLN PIC technology and heterogenous/hybrid integration/packaging of high-power III-V laser chip. Our approach reduces risk by using mature, high-performance III-V technology in the telecom band to generate NIR light at 778.1nm. The proposed approach includes a series of key innovations: I) It is intrinsically immune to back reflection of light; II) It offers high-performance broadband non-magnetic optical isolation with low insertion loss; III) It enables direct integration with electro-optic functionalities on a single chip; IV) It enables wafer-scale mass manufacturing at the foundry level. The combination of these innovations leads to a novel chip-scale integrated laser that offers superior linewidth (<10kHz), optical power (>40mW), optical isolation (>30dB), while with dramatically reduced size, weight, power consumption, and cost (SWaP-C), which will be ideally suited for Air Force applications in optical and atomic clocks.