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Updated: Jun 23, 2026
11:08
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Direct characterization of a nonlinear photonic circuit's wave function with laser light
Francesco Lenzini1, Alexander N Poddubny2,3,4, James Titchener2
1Centre for Quantum Dynamics, Griffith University, Brisbane, QLD 4111, Australia.
Light, Science & Applications
|March 7, 2019
Summary
Researchers developed a fast method to characterize quantum states from integrated photonic circuits. This technique uses classical measurements to precisely evaluate complex nonlinear quantum photonic networks.
Area of Science:
- Quantum optics and integrated photonics
- Development of quantum technologies
Background:
- Integrated photonics is crucial for quantum technologies like state generation, computation, and communication.
- Characterizing complex photonic circuits is challenging due to the impracticality of full quantum tomography.
Purpose of the Study:
- To propose and demonstrate an efficient method for characterizing two-photon states from nonlinear optical circuits.
- To overcome limitations of previous characterization methods for lossy, multi-mode devices.
Main Methods:
- Established a correspondence between quantum states and classical sum-frequency generation measurements.
- Applied the protocol to a multi-channel nonlinear waveguide network.
Main Results:
- Demonstrated a fast and reliable method for reconstructing two-photon states.
- Achieved a high fidelity of 99.28±0.31% between classical and quantum characterization.
- Successfully evaluated a multi-channel nonlinear waveguide network.
Conclusions:
- The developed technique enables fast and precise evaluation of nonlinear quantum photonic networks.
- This is a crucial advancement for the production of complex, large-scale quantum devices.
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01:28Standing Waves in a Cavity
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
01:26Linear Approximation in Frequency Domain
Linear systems are characterized by two main properties: superposition and homogeneity. Superposition allows the response to multiple inputs to be the sum of the responses to each individual input. Homogeneity ensures that scaling an input by a scalar results in the response being scaled by the same scalar.
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear.
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear.