Optical Transmitter Receiver Polarization Multiplexing Control Signal
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Solution Overview
Problem
Existing optical transmission and reception systems face challenges in transmitting and receiving control information without deteriorating the primary signal, particularly due to frequency offset and dependency on the demodulation state of the primary signal.
Innovation Solution
The system employs a transmitter with a known signal generator and control signal modulator to polarization-multiplex control information with a primary signal, using time-division multiplexing and differential coding, and a receiver with a control signal demodulator that extracts phase relationships between polarized wave components to demodulate control information, independent of the primary signal's demodulation state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If frequency-modulated auxiliary control information is superimposed into the primary signal, then control information can be transmitted, but the primary signal is deteriorated due to frequency offset
Solution Approach 1:
The patent divides the optical signal into two separate polarization modes (orthogonal polarizations). Control information is modulated onto one polarization mode while the primary signal is modulated onto the other polarization mode. This segmentation allows independent transmission and reception of control and primary signals without mutual interference, resolving the contradiction between control information transmission and primary signal quality.
Solution Approach 2:
The patent uses polarization multiplexing as an intermediary mechanism to separate control information and primary signal transmission. By encoding control information in the polarization state of the optical carrier, the system creates an independent transmission channel that does not suffer from frequency offset affecting the primary signal, thus maintaining primary signal quality while enabling control information transmission.
2Loss of information
If control information is transmitted by superimposing frequency-modulated signals, then auxiliary information can be sent, but the system becomes dependent on the demodulation state of the primary signal
Solution Approach 1:
The patent segments the transmission channel into two independent polarization modes, allowing control information to be transmitted in one mode while the primary signal is transmitted in the other. This independence eliminates the dependency on primary signal demodulation success, as control information can be extracted directly from its dedicated polarization channel without requiring successful demodulation of the primary signal.
Solution Approach 2:
The patent applies preliminary action by encoding control information into the polarization state of the optical carrier before transmission. This pre-modulation of control information in the polarization domain allows the receiver to extract control information through polarization analysis without needing to successfully demodulate the primary signal first, thereby eliminating demodulation dependency.
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 the transmission and reception of control information without deteriorating the primary signal and without relying on the demodulation state of the primary signal, ensuring robustness against frequency offset and other transmission line variations.
Implementation Method 1
a polarization-multiplexer configured to apply electro-optical transduction on the output signals of the known signal generator and the control signal modulator
Implementation Method 2
a reception-transducer configured to receive the optical signal outputted from the transmitter and to transduce the received optical signal into a digital received-signal separated into every polarized wave component
Data Source
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AI summary
An optical transmission and reception system includes a transmitter (10) and receiver (20). The transmitter (10) differentially encodes control information to generate a differentially coded signal; uses the differentially coded signal to modulate a signal sequence in which electric power concentrates at a particular frequency; applies time-division multiplexing on a primary signal in one of two polarized wave components, and applies time-division multiplexing on a primary signal in the other polarized wave components and the signal sequence itself; polarization-multiplexes the both of the time-division multiplexed polarized waves into an optical signal; and transmits the optical signal to the receiver (20). The receiver (20) polarization-demultiplexes the received optical signal to generate two polarized wave signals; extracts the signal sequence in which electric power concentrates at the particular frequency from the two polarized wave signals; and applies differential detection on the extracted signal sequence to demodulate the control information.