Integrated balanced homodyne photonic–electronic detector for beyond 20 GHz shot-noise-limited measurements

Abstract

Optical homodyne detection is used in numerous quantum and classical applications that demand high levels of sensitivity. However, performance is typically limited due to the use of bulk optics and discrete receiver electronics. To address these performance issues, in this work we present a co-integrated balanced homodyne detector consisting of a silicon photonics optical front end and a custom integrated transimpedance amplifier designed in a 100 nm GaAs pHEMT technology. The high level of co-design and integration provides enhanced levels of stability, bandwidth, and noise performance. The presented detector shows a linear operation up to 28 dB quantum shot noise clearance and a high degree of common-mode rejection, at the same time achieving a shot-noise-limited bandwidth of more than 20 GHz. The high performance of the developed devices provide enhanced operation to many sensitive quantum applications such as continuous variable quantum key distribution, quantum random number generation, or high-speed quantum tomography.