Integrated Photonic Reflection Controlling Circuit for Attached Laser Stabilization

Author(s):

Valerie J. Yoshioka, Pak S. Cho, and Justin R. Bickford

Abstract:

To achieve stable laser operation in a photonic integrated circuit (PIC) system, we implemented an on-chip reflection controlling circuit (RCC), which controls the phase and amplitude of reflections from the on-chip system back into the laser. By adjusting the phase of the back-reflected light, we can prevent or induce instability in laser operation at a given operation point using on-chip controls rather than external isolation. In this work, we characterize the stability of a distributed feedback laser diode at 1550 nm that is photonically wire bonded to an on-chip PIC system. Although internal losses in the PIC system were sufficiently high to prevent measurable laser instability from intrinsic back reflections, we used the RCC to force the laser between stable and unstable modes of operation, demonstrating its utility in controlling laser dynamics. As system losses improve in future iterations of our PIC devices, intrinsic back reflections have the potential to induce instability, necessitating on-chip control methods to stabilize lasing.