Holographic Data Storage Single-Arm Optical Path
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Solution Overview
Problem
Conventional holographic data storage devices with dual-arm structures face issues of compactness and anti-interference stability, which are critical problems in practical applications.
Innovation Solution
A holographic storage system with a single-arm structure is developed, integrating parts of the signal and reference arms, using a spherical wave reference light shift multiplexing method, and incorporating two polarizing beam splitters as a beam combiner and splitter, along with a relay lens group that includes a filter, allowing for beam combining and filtering, and a lens on an actuator for error compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual-arm structure is used for holographic data storage, then the system can process signal and reference beams separately, but the device complexity and system volume increase
Solution Approach 1:
The patent merges the signal arm and reference arm into a single integrated optical path. The beam expander, spatial light modulator, and relay lens group are shared by both signal and reference beams, eliminating the need for separate dual-arm structures while maintaining the ability to process both beams independently through polarization separation and sequential beam combining/splitting operations
2Reliability
If a dual-arm structure is used for holographic data storage, then beam processing is feasible, but the system volume increases
Solution Approach 1:
The patent combines the signal and reference beam paths into a compact single-arm configuration. Shared optical components including the beam expander, spatial light modulator, and relay lens group significantly reduce the overall system volume compared to separate dual-arm structures, while the polarization-based beam combining and splitting enables independent beam processing within the reduced footprint
3Ease of operation
If separate optical paths are used for signal and reference beams, then beam processing is enabled, but anti-interference stability deteriorates
Solution Approach 1:
The patent merges the optical paths such that signal and reference beams traverse the same relay lens group and share the same optical environment. This ensures that environmental interference (temperature changes, vibrations, air currents) affects both beams equally, maintaining their relative phase relationship and improving anti-interference stability while polarization-based beam combining/splitting enables continued beam processing capability
Solution Approach 2:
The patent creates a homogeneous optical environment for both signal and reference beams by having them pass through the same optical components and physical space. This homogeneity ensures that environmental factors affect both beams uniformly, preserving their interference pattern stability and enhancing anti-interference performance
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 design reduces the number of optical and mechanical elements, decreases system volume and cost, and enhances stability by equally impacting environmental interference on both signal and reference beams, while maintaining performance.
Implementation Method 1
a beam expander, and a first half-wave plate; light emitted from the light source emitter is processed by the beam expander and the first half-wave plate
Implementation Method 2
a first half-wave plate; light emitted from the light source emitter is processed by the beam expander and the first half-wave plate and then incident to the beam combining unit; and the first half-wave plate is configured to adjust a beam intensity ratio
Implementation Method 3
the beam combining unit converts the input light into a signal beam and a reference beam which are coaxial and have orthogonal polarization directions
Implementation Method 4
the transmitted signal beam is loaded with an input signal by a spatial light modulator
Implementation Method 5
A relay lens group including a filter is disposed between the beam combiner and the beam splitter, and can transmit and filter patterns on a spatial light modulator. When Fourier holography is used, the filter can also control the size of a hologram on a storage medium
Implementation Method 6
the signal beam and the reference beam are incident to the storage medium at a certain angle and interfere to form a hologram
Implementation Method 7
a lens in the relay lens group is fixed on an actuator that can move in the optical axis direction or the shift multiplexing direction. If the conditions of reading and recording are different due to changes in medium temperature, etc., the actuator is controlled to compensate for an error
Data Source
AI summary
The present invention relates to a holographic data storage device with a single-arm structure, and belongs to the technical field of optical holographic storage. According to the device disclosed in the present invention, a part of a reference arm and a part of a signal arm are integrated together to form a single-arm structure, which can not only reduce the number of optical and mechanical elements, but also reduce the system volume and cost without degrading performance. In addition, a signal beam and a reference beam share the same relay lens, so that the impact of environmental interference on the two beams is equal, and the stability of the entire system is improved.