Optical Phased Array Grating Structure for Tx/Rx Crosstalk Separation
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Solution Overview
Problem
In optical phased array (OPA) architectures, the simultaneous transmission and reception of signals using a common aperture leads to scattering of strong transmit signals into the weaker receive signal channel, necessitating additional separation components, which complicates the design and impairs signal detection.
Innovation Solution
Incorporating an additional grating structure, such as an Echelle grating, at the entrance aperture of the OPA chip to separate transmit and receive signals by dispersing different wavelengths, allowing them to focus on separate emitters within the micro-lens array, thereby reducing the need for additional separation components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common aperture is used for both transmitting and receiving signals in an optical phased array, then the device complexity is reduced, but the transmit signals scatter into the receive signal channel causing crosstalk and impairing signal detection
Solution Approach 1:
The patent divides the signal paths by implementing separate emitter arrays for transmit and receive functions, and separate detector arrays for different wavelength channels. This segmentation prevents transmit signals from scattering into the receive channel by creating physically distinct optical paths for each function.
Solution Approach 2:
The patent introduces wavelength division as an additional dimension for signal separation. By assigning different wavelength ranges to transmit and receive signals, and using wavelength-selective detectors, the system can separate signals that share the same spatial aperture, effectively adding a spectral dimension to the signal separation problem.
2Measurement precision
If additional separation components are added to prevent transmit signal scattering, then signal detection quality improves, but the device complexity increases
Solution Approach 1:
The patent combines multiple functions into integrated photonic circuits on single chips. The emitter arrays, detector arrays, waveguides, and wavelength-selective elements are merged into compact integrated structures, reducing the overall system complexity despite the added functional separation requirements.
Solution Approach 2:
The patent designs photonic integrated circuits that perform multiple functions within single components. For example, the waveguide structures serve both as signal transmission paths and as wavelength-selective elements through their geometric design, eliminating the need for separate filtering components.
3Productivity
If wavelengths for transmit and receive signals are kept close together, then the spectral efficiency improves, but the ability to separate signals at the receiver deteriorates
Solution Approach 1:
The patent changes the separation parameter from wavelength-based filtering to geometric/path-based separation. By using physically distinct emitter and detector arrays with controlled optical paths, the system can separate signals even when their wavelengths are very close, achieving both spectral efficiency and effective signal separation.
Solution Approach 2:
The patent replaces traditional mechanical or bulky optical filtering systems with integrated photonic circuit structures. The wavelength-selective behavior is achieved through the geometric design of waveguides and coupling structures rather than through separate filtering components, enabling compact implementation with closely spaced wavelengths.
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
The solution effectively separates transmit and receive signals, enabling bidirectional communication with closely spaced wavelengths, reducing complexity and improving signal detection by eliminating crosstalk and the need for additional separation components.
Implementation Method 1
Incorporating an additional grating structure, such as an Echelle grating, at the entrance aperture of the OPA chip to separate transmit and receive signals by dispersing different wavelengths
Implementation Method 2
allowing them to focus on separate emitters within the micro-lens array
Data Source
AI summary
Aspects of the disclosure provide for a system including a first communications terminal. The first communications terminal may include a common aperture for transmitting signals and receiving signals and an optical phased array (OPA) architecture. The OPA architecture may include including a micro-lens array including a plurality of micro-lenses, each micro-lens of the plurality of micro-lenses having an additional grating structure on a surface of that micro-lens and being associated with a first pair of emitters, and each one of the pair of emitters being associated with a phase shifter. The OPA architecture may be configured for bidirectional communication with a second communications terminal.