(a) Schematics of the experimental setup for imaging waves propagating in photonic devices. The 1550 nm signal pulses (orange) are grating coupled into a silicon-on-insulator (SOI) waveguide, while the 780 nm pump pulses (red) are focused onto the device at the using a long working distance lens. When the two pulses overlap in time and space, a nonlinear wave is generated (green), separated from the pump by a dichroic mirror (DM), and collected by a standard CMOS camera. P, F, and 𝜆/2 represent the linear polarizer, spectral filter, and 𝜆/2 waveplate, respectively. (b) Definitions of the axes and directions of propagation of the pump beam (normal incidence), the signal beam (guided along the waveguide), and the nonlinearly generated beam (reflected at an angle versus the vector waveform of the signal wave). (c) Cross section of the single waveguide. Credit: Optical (2023). DOI: 10.1364/OPTICA.504397
The field of photonic integrated circuits focuses on miniaturizing photonic elements and integrating them into photonic chips, circuits that perform a range of calculations using photons, rather than electrons like those used in electronic circuits.
Silicon-based photonics is a developing field relevant to data centers, artificial intelligence, quantum computing, and more. It makes it possible to considerably improve the performance of chips and their cost-benefit ratio because it is based on the same raw material as chips, very widespread in the world of electronics.
However, although they benefit from a well-developed lithographic production process, which allows precise production of the desired devices, the instruments do not yet allow precise mapping of the optical characteristics of the chip. This includes the movement of internal light – a crucial capability given the difficulty of modeling the effect of manufacturing defects and inaccuracies – due to the devices’ tiny dimensions.
A new paper by Technion Faculty of Electrical and Computer Engineering researchers Andrew and Erna Viterbi tackles this challenge, showing advanced light imaging in photonic circuits on chips. The research, published in the journal Optical, was led by Professor Guy Bartal, head of the Advanced Photonics Research Laboratory, and doctoral student Matan Iluz, in collaboration with the research group of Professor Amir Rosenthal. Graduate students Kobi Cohen, Jacob Kheireddine, Yoav Hazan and Shai Tsesses also participated in the research.
The researchers exploited the optical characteristics of silicon to map the propagation of light without requiring invasive action of any kind that could disrupt or alter the chip. This process includes mapping the electric field of light waves and defining the elements that affect the movement of light: waveguides and beam splitters.
The process provides real-time images and video recordings of the light inside the photonic chip, without having to damage the chip and without losing data. This new process is expected to improve the design, production and optimization processes of photonic chips in various fields, including telecommunications, high-performance computing, machine learning, distance measurement, medical imaging, sensing and quantum computing.
More information:
Matan Iluz et al, Unveiling the Evolution of Light in Photonic Integrated Circuits, Optical (2023). DOI: 10.1364/OPTICA.504397
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Quote: New research shows how light propagates in integrated circuits on chips (January 31, 2024) retrieved January 31, 2024 from
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