ContactLess Integrated Photonic Probe for light monitoring in InP-based devices

TL;DR

This paper introduces a non-invasive, contactless photonic probe (CLIPP) for monitoring light in InP-based integrated circuits, enabling more accurate and scalable circuit stabilization without affecting circuit response.

Contribution

The paper presents a novel vertical CLIPP design that reduces device footprint and simplifies electrical connections, improving light monitoring in large photonic circuits.

Findings

CLIPP effectively monitors power without circuit interference

Vertical scheme reduces device size and complexity

Demonstrated improved accuracy over traditional detectors

Abstract

The increasing complexity of photonic integrated circuits requires the possibility to monitor the state of the circuit in order to stabilize the working point against environmental fluctuations or to perform reliable reconfiguration procedures. Although InP technologies can naturally integrate high-quality photodiodes, their use as tap monitors necessarily affects the circuit response and is restricted to few units per chip. They are hence unsuited for very large circuits, where transparent power monitors become key components. In this paper we present the implementation of a ContactLess Integrated Photonic Probe (CLIPP) realizing a non invasive integrated light monitor on InP-based devices. We describe an innovative vertical scheme of the CLIPP monitor which exploits the back side of the chip as a common electrode, thus enabling a reduction of the device footprint and a simplification of the electrical connectivity. We characterize the response of the CLIPP and demonstrate its functionality as power monitor. Lastly, we provide a direct demonstration that CLIPP monitor allows to access more accurate information on the working point of photonic integrated circuits compared to conventional external or integrated photodetectors.