Optical Resonator Cavity Tuning for Beam-Pointing-Stable Reception
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Solution Overview
Problem
Optical communication systems face challenges in adapting to varying wavelengths, modulation formats, and data rates without requiring coherent receivers or adaptive optics, particularly in free-space optical communications where beam pointing and optical resonator tuning are critical.
Innovation Solution
An optical receiver with a tunable optical resonator assembly, such as a Fabry-Perot etalon, adjusts its optical thickness or length using temperature or piezoelectric actuators to optimize the operating point based on signal characteristics, enabling dynamic adaptation to changing conditions without external feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the optical resonator is tuned to optimize the operating point for different wavelengths and modulation formats, then the receiver can adapt to varying signal characteristics, but the device complexity increases due to required tuning mechanisms
Solution Approach 1:
The patent applies parameter changes by tuning the optical resonator's physical parameters (cavity length, refractive index) to optimize the operating point for different wavelengths and modulation formats. The controller dynamically adjusts these parameters based on detected signal characteristics, enabling the receiver to adapt to varying input conditions without requiring multiple fixed resonators or complex coherent detection systems.
2Adaptability or versatility
If temperature control is used to tune the optical resonator, then the operating point can be optimized for different signal characteristics, but the response time may be limited by thermal inertia
Solution Approach 1:
The patent implements dynamics by providing a dual-tuning mechanism: slow thermal tuning for coarse adjustment of the resonator's operating point, and fast piezoelectric tuning for rapid fine-adjustment. This hierarchical approach allows the system to optimize the operating point for different signal characteristics while maintaining fast response times when beam pointing changes occur, effectively combining the advantages of both slow and fast tuning methods.
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 system effectively converts modulated optical signals into intensity-modulated outputs, allowing for reliable demodulation across different wavelengths, modulation formats, and data rates, maintaining beam pointing without additional hardware, and correcting for environmental disturbances.
Implementation Method 1
an optical resonator configured to receive an input optical signal, to accumulate optical signal energy inside the at least one optical resonator
Implementation Method 2
In one example, the at least one optical cavity resonator is a Fabry-Perot etalon
Implementation Method 3
the at least one optical cavity resonator further includes a piezoelectric actuator coupled to at least one of the first and second semi-reflective surfaces, and the controller is configured to apply the first control signal to the at least one piezoelectric actuator to move a corresponding at least one of the first and second semi-reflective surfaces
Implementation Method 4
produce an intensity modulated output optical signal, an intensity modulation of the output optical signal being representative of a modulation of the input optical signal
Data Source
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Figure 3~3A
AI summary
Disclosed are optical communications systems and optical receivers including one or more optical cavity resonators. In particular, disclosed are methods and apparatus that allow for beam pointing to be maintained while permitting the receiver to tune the optical length of the optical resonator to suit the wavelength, data rate and modulation format of the incoming optical signal, without requiring a coherent receiver or adaptive optics in addition to optical resonators.