Tunable True Time Delay Photonic Circuit
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Solution Overview
Problem
Existing true time delay hardware using low-loss fiber optic waveguides is cumbersome due to the extreme burden on design and fabrication of the switch matrix, resulting in a large footprint and increased weight.
Innovation Solution
A compact photonic circuit with a plurality of waveguides of different lengths, integrated demultiplexer, and multiplexer on a single substrate, where the wavelength of a tunable laser is used to select the desired time delay, allowing for tunable true time delay and additional selectable delays through additional photonic circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large N×M switch matrix is used to couple light into fiber optic waveguides, then true time delay functionality is achieved, but device complexity and footprint increase significantly
Solution Approach 1:
The patent extracts the switching function from a complex N×M switch matrix and replaces it with a simple wavelength-selective mechanism. By using wavelength division multiplexing, the delay selection is achieved through wavelength routing rather than complex switching, eliminating the need for a large switch matrix while maintaining true time delay functionality.
Solution Approach 2:
The patent replaces the mechanical/electrical switching system with an optical wavelength-based selection system. Instead of using switches to route signals through different delay paths, the system uses wavelength-specific routing where different wavelengths automatically follow different delay paths, substituting a complex switching mechanism with a simpler optical filtering approach.
2Reliability
If fiber optic waveguides and switch matrix are used, then true time delay is achieved, but footprint and weight increase
Solution Approach 1:
The patent merges the delay lines and switching functionality into a single integrated photonic circuit structure. By combining multiple delay paths into one compact device with wavelength-selective routing, the overall footprint and weight are reduced while maintaining the true time delay functionality across multiple channels.
Solution Approach 2:
The patent transitions from a two-dimensional planar layout with extensive fiber paths to a three-dimensional integrated photonic structure. By stacking delay lines and using vertical coupling structures, the system achieves compact packaging that reduces footprint and weight while maintaining all necessary delay paths.
3Adaptability or versatility
If fiber optic waveguides with different lengths are used, then different time delays are achieved, but fabrication complexity increases
Solution Approach 1:
The patent uses wavelength as the controlling parameter for delay selection instead of physically switching between different fiber lengths. By encoding delay selection in the wavelength domain, the system achieves multiple selectable delay values without requiring complex fabrication of switchable fiber length configurations, simplifying the manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a compact and lightweight solution for tunable true time delay, enabling adjustable time delays with reduced complexity and size, suitable for applications like beamforming and phased array antennas.
Implementation Method 1
A particular one of the waveguides corresponding to a desired time delay is selected by tuning the wavelength of a tunable laser
Implementation Method 2
The photonic circuit comprises a plurality of waveguides, in which each waveguide corresponds to a different time delay
Data Source
AI summary
Described are systems and methods that provide tunable true time delay of a signal using a compact photonic circuit. The photonic circuit comprises a plurality of waveguides, in which each waveguide corresponds to a different time delay. A particular one of the waveguides corresponding to a desired time delay is selected by tuning the wavelength of a tunable laser. Additional photonic circuits can be used to provide additional selectable time delays.