Parallel Optical Sampler for High-Bandwidth Signal Conversion
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Solution Overview
Problem
Current electronic analog-to-digital converters (ADCs) are limited by jitter and cannot meet the demands for high-bandwidth, high-resolution sampling required for advanced applications such as optical communications, radar, and radio astronomy, as they require complex time-division demultiplexing which complicates the sampling process.
Innovation Solution
An optical sampler monolithically integrated on a single IC substrate using time delayed parallel sampling, which includes parallel optical modulators and photodiodes to generate successive optical samples of the input signal with reduced jitter, avoiding complicated time-division demultiplexing in the optical domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If time-division demultiplexing is used to increase sampling bandwidth, then the bandwidth demand is relieved, but the system complexity and jitter increase
Solution Approach 1:
The invention divides the high-bandwidth sampling task into multiple parallel optical modulators, each handling a portion of the signal. By segmenting the sampling process across multiple channels that operate simultaneously rather than sequentially, the system achieves high effective bandwidth without requiring complex time-division demultiplexing circuits, thus avoiding the associated jitter and complexity penalties.
Solution Approach 2:
The invention replaces electronic time-division demultiplexing mechanisms with parallel optical modulation. Instead of using electronic switches and multiplexers to sequentially process different signal portions, the system uses multiple optical modulators that operate in parallel, substituting optical-domain processing for electronic-domain processing to eliminate jitter and simplify the system.
2Speed
If electronic ADCs are used to achieve high sampling rates, then the conversion speed increases, but jitter limits the resolution
Solution Approach 1:
The invention substitutes electronic sampling and conversion mechanisms with optical modulation and detection. By using optical modulators driven by a high-speed clock signal and optical-to-electrical converters, the system achieves high sampling rates without the jitter inherent in electronic ADCs, thereby maintaining both speed and precision.
Solution Approach 2:
The invention employs periodic optical sampling using a high-frequency clock signal to modulate multiple optical carriers simultaneously. This periodic action across multiple channels enables high effective sampling rates while the optical domain operation maintains precision by avoiding electronic jitter accumulation.
3Measurement precision
If parallel optical modulators are used for time delayed parallel sampling, then jitter is reduced and fidelity improves, but device complexity increases
Solution Approach 1:
The invention merges multiple optical modulation functions into a single integrated photonic device structure. By combining multiple modulators, delay lines, and signal paths into one monolithic chip, the system achieves high sampling fidelity through parallel processing while reducing overall device complexity compared to assembling separate components.
Solution Approach 2:
The invention designs a universal photonic sampling platform that can handle multiple signal channels and sampling rates using the same basic building blocks. The parallel optical modulator architecture provides multi-functionality, enabling the system to achieve high fidelity sampling across different applications without requiring application-specific custom designs.
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 enables higher fidelity and speed in analog-to-digital conversion, allowing for real-time processing of optical signals and supporting applications like optical transmission links, advanced radar, and spread spectrum communications without the need for complex demultiplexing, thereby overcoming the limitations of current electronic ADCs.
Implementation Method 1
The photodiode converts a respective one of either a) n parallel optical analog input signals or b) n parallel input optical sampling signals to an electrical out signal
Implementation Method 2
The electrical output signal modulates a relative phase of two branches of the MZM so that the MZM produces a differential pair of optical output signals
Implementation Method 3
n semiconductor optical amplifiers (SOA) amplifying either a) n parallel optical analog input signals or b) n parallel input optical sampling signals
Data Source
AI summary
An optical sampler includes a first and second 1×n optical beam splitters splitting an input optical sampling signal and an optical analog input signal into n parallel channels, respectively, a plurality of optical delay elements providing n parallel delayed input optical sampling signals, n photodiodes converting the n parallel optical analog input signals into n respective electrical output signals, and n optical modulators modulating the input optical sampling signal or the optical analog input signal by the respective electrical output signals, and providing n successive optical samples of the optical analog input signal. A plurality of output photodiodes and eADCs convert the n successive optical samples to n successive digital samples. The optical modulator may be a photodiode interconnected Mach-Zehnder Modulator. A method of sampling the optical analog input signal is disclosed.