Variable Spectral Phase Encoder Using Hadamard Code Decomposition
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Solution Overview
Problem
Existing optical CDMA networks face limitations in scalability and rapid reconfiguration of dynamic encoders/decoders, which restrict the number of users and data rates due to the need for adjustable phase masks and multiple coder units, leading to inefficiencies in noise reduction and spectral phase encoding.
Innovation Solution
A spectral phase encoder/decoder system utilizing a cascade of 2x2 optical crossbar switches and Walsh encoders/decoders, allowing for rapid reconfiguration and scalability by applying Hadamard sequences, reducing the number of adjustable elements required and enabling microsecond to nanosecond timescale changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adjustable phase masks and multiple coder units are used in optical CDMA networks, then encoding capability is improved, but device complexity and scalability are worsened
Solution Approach 1:
The optical CDMA encoder is segmented into multiple fixed coders that process different segments of the code sequence. Each fixed coder handles a specific portion of the Hadamard code, allowing the system to achieve complex encoding capability through composition of simpler fixed units rather than requiring a single complex adjustable phase mask.
Solution Approach 2:
The system achieves dynamic reconfiguration capability not through adjustable phase masks but through temporal switching between fixed coders. The dynamic behavior is achieved by controlling which fixed coders are active at different time intervals, enabling rapid code changes at microsecond to nanosecond timescales without mechanical adjustments.
2Quantity of substance
If multiple coder units are used to support more users, then user capacity is improved, but the number of adjustable elements increases
Solution Approach 1:
Each fixed coder unit is designed to be multi-functional, capable of serving multiple users through temporal multiplexing. The same fixed coder can be assigned to different users at different time intervals, allowing a single fixed coder to replace what would traditionally require multiple dedicated coder units, thereby supporting user capacity growth without linearly increasing the number of adjustable elements.
Solution Approach 2:
The system uses dynamic time-division multiplexing to assign fixed coders to different users. By rapidly switching which fixed coder serves which user in different time slots, the system achieves high user capacity without requiring each user to have dedicated adjustable phase mask elements. This dynamic allocation allows N users to be supported with far fewer than N adjustable elements.
3Adaptability or versatility
If mechanical or thermal adjustments are used for phase mask reconfiguration, then code changes are achieved, but reconfiguration speed is limited
Solution Approach 1:
The system replaces mechanical adjustment mechanisms (such as moving parts in adjustable phase masks) with electronic/optical switching of fixed coders. This substitution eliminates the speed limitations of mechanical systems while achieving the same code reconfiguration function through electronic control of switch states, enabling reconfiguration at microsecond to nanosecond timescales.
Solution Approach 2:
Instead of physically adjusting phase mask parameters through mechanical or thermal means, the system changes the operational parameters by switching between pre-configured fixed coders. The code reconfiguration is achieved by changing which fixed coder is active, not by adjusting the physical parameters of a single coder, thereby achieving rapid reconfiguration without mechanical or thermal processes.
Data Source
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AI summary
The invention is directed toward a variable spectral phase encoder. The variable spectral phase encoder includes a plurality of switches and at least one encoder. The encoder is coupled between a first switch and second switch among the plurality of switches. The first switch selectively routes an optical signal to some combination of fixed encoders such that their collective product applies one of the Hadamard sequences to the optical signal.