Optical Phased Array Crosstalk Suppression via Phase Perturbations
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Solution Overview
Problem
Existing optical phased array beam steering technologies face challenges in efficiently steering light beams into multiple directions while minimizing optical crosstalk, which degrades performance in fiberoptic communication networks due to the limited number of phase delay elements and computation-intensive methods for reducing crosstalk.
Innovation Solution
An array of tunable phase delay elements is used to modify the wavefront of light waves, with a controller applying initial control signals and perturbations to suppress light propagation in undesired directions through destructive interference, allowing the light to propagate in a selected subset of directions while minimizing crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an array of tunable phase delay elements is used to steer light beams in multiple directions, then the beam steering capability is improved, but optical crosstalk increases and degrades network performance
Solution Approach 1:
The patent applies preliminary anti-action by calculating and applying perturbations to the initial control signals before light propagation occurs. These perturbations are specifically designed to generate anti-phase light waves that will destructively interfere with potential crosstalk in undesired directions, preventing crosstalk formation rather than addressing it after it occurs.
Solution Approach 2:
The patent converts the harmful optical crosstalk into a beneficial effect by using the same phased array mechanism that causes crosstalk to instead create controlled destructive interference. By applying perturbations to the control signals, the system generates anti-phase waves that target and cancel crosstalk in undesired directions, transforming the potential harm into a crosstalk suppression mechanism.
2Object-generated harmful factors
If conventional phased array methods are used to reduce crosstalk, then crosstalk suppression is achieved, but the computational complexity and time requirements increase significantly
Solution Approach 1:
The patent implements preliminary action by pre-calculating the perturbations to control signals based on the desired beam directions and the known geometry of the phased array. This preparation is done before the actual light steering operation, allowing the system to quickly apply the pre-computed perturbations without requiring real-time complex calculations during operation.
Solution Approach 2:
The patent changes the parameters of the control signals by applying specific perturbations that modify the phase and amplitude characteristics. These parameter changes are designed to create the necessary anti-phase interference patterns while maintaining the primary beam steering function, achieving crosstalk suppression through optimized signal parameters rather than complex post-processing.
3Measurement precision
If the number of phase delay elements is increased to improve beam steering precision, then the steering accuracy is improved, but the device complexity and cost increase
Solution Approach 1:
The patent achieves improved steering accuracy without increasing the number of elements by changing the operational parameters of the existing phase delay elements. By applying perturbations to the control signals, the system optimizes the phase and amplitude parameters to enhance beam directionality and reduce sidelobes, achieving higher effective precision from the same hardware configuration.
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 effectively reduces optical crosstalk by up to 20 dB, improving the performance of fiberoptic communication networks by allowing simultaneous coupling of light signals into multiple output fibers with reduced sidelobes and increased accuracy in steering light beams.
Implementation Method 1
an array of tunable phase delay elements disposed to interact with the light wave, for modifying the wavefront of the light wave
Implementation Method 2
determining perturbations to the initial control signals, for sending, in the subset B of directions, a wave having the modulus of the complex amplitude equal to the modulus of the initial complex amplitude, and the phase of the complex amplitude opposite to the phase of the initial complex amplitude
Data Source
AI summary
An apparatus and method for steering a beam of light using an array of tunable optical phase delay elements is presented. The sidelobes of an angular spectrum of light reflected from the array are causing an optical crosstalk. The selected sidelobes are suppressed by perturbing the phase delay pattern of the array elements. The pattern of perturbations is found by linearizing a system of equations describing dependence of the angular spectrum of the reflected light on the phase delays introduced into the wavefront of light by the elements of the array.