Ultra-precise optical-frequency stabilization with heterogeneous III–V/Si lasers
Liron Stern, Wei Zhang, Lin Chang, Joel Guo, Chao Xiang, Minh A. Tran, Duanni Huang, Jonathan D. Peters, David Kinghorn, John E. Bowers, Scott B. Papp
Abstract
The demand for low-noise, continuous-wave, frequency-tunable lasers based on semiconductor integrated photonics has advanced in support of numerous applications. In particular, an important goal is to achieve a narrow spectral linewidth, commensurate with bulk-optic or fiber-optic laser platforms. Here we report on laser-frequency-stabilization experiments with a heterogeneously integrated III/V-Si widely tunable laser and a high-finesse, thermal-noise-limited photonic resonator. This hybrid architecture offers a chip-scale optical-frequency reference with an integrated linewidth of 60 Hz and a fractional frequency stability of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>2.5</mml:mn> <mml:mo>×</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>−</mml:mo> <mml:mn>13</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> at 1 s integration time. We explore the potential for stabilization with respect to a resonator with lower thermal noise by characterizing laser-noise contributions such as residual amplitude modulation and photodetection noise. Widely tunable, compact and integrated, cost-effective, stable, and narrow-linewidth lasers are envisioned for use in various fields, including communication, spectroscopy, and metrology.