Optical Digital-to-Analog Converter With Intensity-Weighted Splitting
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Solution Overview
Problem
Optical digital-to-analog converters (DACs) using optical circuits face limitations in speed and density due to reliance on electric circuits and require a large number of elements and circuit size.
Innovation Solution
An optical DAC design incorporating a first splitter to differentiate light beams by intensity, an optical intensity modulator to individually modulate these beams based on digital signal bits, and a combiner to combine them, achieving high speed and high density with low loss and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an optical DAC uses an optical circuit, then speed is improved, but device complexity increases due to requiring a great number of elements
Solution Approach 1:
The optical signal is segmented into N separate light beams corresponding to N bits of digital signal, with each beam processed independently through dedicated optical intensity modulators. This segmentation allows parallel processing of multiple bits simultaneously, achieving high-speed operation while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The patent transitions from electrical domain processing to optical domain processing by using optical circuits instead of electrical circuits. This dimensionality change from electrical to optical enables higher speed operation while using a systematic approach to manage the number of optical elements required.
2Speed
If an optical DAC uses an optical circuit, then speed is improved, but circuit size increases
Solution Approach 1:
N light beams are merged/combined into a single output light beam through optical combining techniques. This merging process consolidates the parallel processed beams into one unified output, reducing the spatial footprint required for the optical circuit while maintaining the high-speed parallel processing capability.
Solution Approach 2:
The patent employs optical domain processing instead of electrical domain, which enables compact integration of multiple functions in a smaller physical footprint. The optical circuit design allows for denser integration compared to electrical circuits, reducing overall circuit size while preserving high-speed performance.
3Measurement precision
If higher resolution is achieved, then measurement precision is improved, but latency increases
Solution Approach 1:
The digital signal is segmented into N bits, with each bit processed simultaneously through dedicated optical intensity modulators. This parallel processing approach allows high-resolution (N-bit) conversion to be achieved without sequential processing delays, thereby maintaining low latency while improving resolution.
Solution Approach 2:
The optical circuit maintains continuous operation by processing all N bits in parallel through simultaneous optical modulation, rather than processing bits sequentially. This continuous parallel action eliminates waiting time between bit processing stages, reducing overall latency while achieving high resolution.
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 enables an optical DAC that operates at high speed and high density with low latency and loss, overcoming the limitations of existing optical DACs by optimizing the configuration of splitters, modulators, and combiners.
Implementation Method 1
a first splitter configured to split a single light beam into N light beams corresponding to bits of an N-bit electrical digital signal
Implementation Method 2
an optical intensity modulator configured to individually intensity-modulate the N light beams which are made different in optical intensities by the first splitter according to corresponding bits of the N-bit electrical digital signal
Implementation Method 3
a combiner configured to combine the N output light beams intensity-modulated by the optical intensity modulator and output the combined light beam
Data Source
AI summary
An optical DAC includes a 1:N splitter that splits a single light beam into N light beams corresponding to bits of an N-bit electrical digital signal (where N is an integer of 2 or more) and makes the N light beams different in optical intensities such that (N−1) light beams corresponding to bits except a least significant bit of the N-bit electrical digital signal each have an optical intensity which is four times as large as an optical intensity of a light beam corresponding to a next less significant bit, an optical intensity modulator that individually intensity-modulates the N light beams, an N:1 combiner that combines the N output light beams intensity-modulated by the optical intensity modulator and outputs the combined light, and a phase shifter that is adjustable such that the light beams that are combined by the N:1 combiner are made in phase.