Reconfigurable Optical Receiver Using Ring Resonators
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Solution Overview
Problem
Conventional optical receivers face challenges in reducing size, weight, and power consumption (SWAP) while maintaining sensitivity and reconfigurability for demultiplexing and demodulating wavelength division multiplexed (WDM) signals, especially in space-based applications where power is limited and versatility is required.
Innovation Solution
The use of ring resonator-based partial drop filtering elements that couple out spectral components at specific wavelengths, allowing for reconfigurable optical receivers with lower loss and fewer components, enabling demultiplexing and demodulation with reduced SWAP and supporting various modulation schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional optical receivers are used for WDM signal demultiplexing and demodulation, then signal processing capability is maintained, but size, weight, and power consumption (SWAP) increase
Solution Approach 1:
The patent combines multiple functional elements (filtering elements, detectors, and comparators) into an integrated optical receiver architecture. The filtering elements are optically coupled to the waveguide to perform wavelength selection, detectors convert optical signals to electrical signals, and comparators process the detector signals to generate demodulated output. This integration reduces the number of discrete components and interconnections, thereby reducing SWAP while maintaining signal processing capability.
Solution Approach 2:
The optical receiver is designed with reconfigurable filtering elements that can be tuned to different wavelengths, enabling the same receiver structure to handle multiple WDM channels and various modulation schemes (FSK, DPSK, OOK). This multi-functionality eliminates the need for separate receivers for different wavelength channels or modulation types, significantly reducing the overall system SWAP.
2Reliability
If conventional optical receivers are used for WDM signal processing, then signal demodulation is achieved, but sensitivity is reduced due to higher losses
Solution Approach 1:
The patent employs filtering elements that are optically coupled to the waveguide to extract specific wavelength components from the WDM signal. This selective extraction minimizes the optical loss by only coupling out the necessary wavelength components while allowing other wavelengths to continue propagating with minimal attenuation. The filtering elements are positioned and designed to optimize the coupling efficiency, thereby reducing overall optical loss and improving receiver sensitivity.
3Adaptability or versatility
If conventional optical receivers are used, then basic demodulation function is provided, but reconfigurability for different modulation schemes is limited
Solution Approach 1:
The patent incorporates reconfigurable filtering elements that can be dynamically tuned to different wavelengths and configured for different modulation schemes. The filtering elements can be adjusted via control signals to change their resonant wavelengths, enabling the receiver to adapt to different WDM channel assignments and modulation formats (FSK, DPSK, OOK) without requiring hardware changes. This dynamic reconfigurability provides versatility while maintaining a compact integrated structure.
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 achieves lower SWAP, improved sensitivity, and reconfigurability, allowing for efficient demultiplexing and demodulation of WDM signals in space-based applications, supporting high data rates and various modulation schemes with reduced power consumption.
Implementation Method 1
A first plurality of ring resonators may be optically coupled to the input waveguide to couple out a first plurality of spectral components in the WDM input signal
Implementation Method 2
A first detector may be optically coupled to the first plurality of ring resonators to generate a first detector signal in response to the first plurality of spectral components
Data Source
AI summary
An optical receiver includes a cascade of optical filtering elements, each of which selects spectral components from incoming optical signals at a wavelengths aligned to filter passbands. The selected spectral components may be optically combined to form k pairs of intermediary signals, where k=log2(M). By comparing the k pairs of intermediary signals, k bits of a digital signal representing the incident signal may be generated. The filtering elements may be configured to perform demultiplexing and demodulation simultaneously, increasing functionality and reducing excess losses. The filtering elements may also be tuned so that the optical receiver may be reconfigured to accommodate different combinations of wavelengths and modulation formats, such as wavelength division multiplexed (WDM) on off keying (OOK), M-ary orthogonal formats including frequency shift keying (FSK) and pulse position modulation (PPM), differential phase shift keying, and hybrid combinations—providing rate and format flexibility and WDM scalability.