Optical Storage DRAW Verification Using Beam Splitting and Digital Noise Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Optical Pickup Units (OPUs) face challenges in directly reading and verifying data during the write operation due to noise contamination from high-power laser beams, leading to a low signal-to-noise ratio and inefficiencies in data recovery.
Innovation Solution
The implementation of an optical storage system with a controller and optical head that splits a light beam into a higher power main beam and a lower power side beam, where the higher power beam is modulated for writing and the lower power beam is used for feedback to remove noise through digital signal processing, allowing for direct read after write (DRAW) capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a higher power laser beam is used for writing data to the optical medium, then the writing speed and data recovery efficiency are improved, but noise is introduced into the reflected signal, degrading the signal-to-noise ratio
Solution Approach 1:
The patent divides the laser beam into multiple separate beams (first beam for writing, second beam for reading) using optical elements like beam splitters or diffractive optical elements. This segmentation allows the high-power writing beam and low-power reading beam to coexist without mutual interference, resolving the contradiction between writing speed and signal quality by spatially separating the functions.
Solution Approach 2:
The patent introduces an intermediary optical element (such as a beam splitter, diffractive optical element, or acousto-optic modulator) that mediates between the high-power writing beam and the reading process. This intermediary directs the writing beam to the medium while allowing the reflected reading beam to be extracted with minimal contamination from the writing beam, thus maintaining both high writing speed and good signal quality.
2Device complexity
If a single laser beam is used for both writing and reading operations, then the device complexity is reduced, but the signal quality deteriorates due to noise from the writing process
Solution Approach 1:
The patent segments the single laser beam into multiple spatially separated beams using optical elements. The first beam is directed for writing operations while the second beam is directed for reading operations. This segmentation enables simultaneous writing and reading with distinct optical paths, maintaining signal quality while using a single laser source.
Solution Approach 2:
The patent resolves the contradiction by adding a spatial dimension to the optical path management. Instead of using temporal separation (writing then reading), the system uses spatial separation of beams at different angles or positions. This dimensional approach allows both writing and reading to occur simultaneously without interference, improving signal quality while maintaining reasonable device complexity.
3Measurement precision
If digital signal processing is applied to remove noise from the reflected signal, then the signal-to-noise ratio is improved, but the processing time and computational complexity increase
Solution Approach 1:
The patent applies preliminary optical filtering and signal conditioning before the digital signal processing stage. Optical elements such as bandpass filters or temporal filtering through acousto-optic modulators pre-clean the signal by removing high-frequency noise components generated during writing. This preliminary action reduces the computational burden on subsequent digital processing, decreasing processing time while maintaining high signal quality.
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 real-time data verification with improved signal quality and reduced noise, achieving high-speed and efficient data recovery during the write operation, with potential for multi-channel operation and cost-effective design.
Implementation Method 1
an optical head that splits a light beam into a higher power main beam and a lower power side beam
Implementation Method 2
modulating the higher power main beam according to writing commands to write to an optical medium
Implementation Method 3
processing first data resulting from the lower power side beam being reflected from the medium
Implementation Method 4
processes the feedback and data representing filtered writing strategy waveforms to remove noise from the feedback caused by the higher power main beam
Data Source
AI summary
An optical storage system includes an optical head configured to split a light beam into a higher power main beam and a lower power side beam. The system also includes a controller. The controller is configured to modulate the higher power main beam according to writing commands to write to an optical medium while processing first data resulting from the lower power side beam being reflected from the medium and second data obtained from a look-up table that maps the writing commands to digital representations of filtered writing strategy waveforms to remove noise from the first data caused by the higher power main beam and generate output indicative of written data directly after writing.