Multi-Carrier Optical Signal Transmission and Reception
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Solution Overview
Problem
Conventional coherent detection in optical communication systems is costly due to the need for a local oscillating optical source, and the limited bandwidth of analog-to-digital converters restricts the spectrum width and transmission rate.
Innovation Solution
A signal transmitting and receiving system that generates multiple optical carriers from a basic carrier, modulates most carriers with data signals, and synthesizes them into a single signal for transmission, eliminating the need for a local oscillator by using generated optical waves for demodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a local oscillating optical source is provided at the receiving side for coherent detection, then detection sensitivity is improved, but system cost increases
Solution Approach 1:
The patent extracts the local oscillating light function from a separate optical source and integrates it into the transmitted signal itself by retaining one unmodulated carrier. This eliminates the need for an independent local oscillating source at the receiving end, reducing system cost while maintaining coherent detection capability
Solution Approach 2:
The transmitted optical signal serves dual functions: it carries modulated data on multiple carriers and simultaneously provides the unmodulated carrier that acts as the local oscillating light for demodulation. This multi-functionality reduces the number of separate components needed in the system
2Device complexity
If the bandwidth of analog-to-digital converter is limited, then device complexity is reduced, but spectrum width and transmission rate are restricted
Solution Approach 1:
The patent segments the data signal into multiple parallel data streams that modulate different optical carriers. By distributing data across multiple frequency channels, the system achieves high total transmission rate while each individual channel operates within the bandwidth capability of the analog-to-digital converter
Solution Approach 2:
The patent transitions from single-channel time-domain transmission to multi-channel frequency-domain transmission. By utilizing the frequency dimension with multiple optical carriers, the system expands the total transmission capacity beyond what a single wide-bandwidth converter could provide
Data Source
AI summary
A signal transmission and reception device and method are provided. The transmission method comprises generating multiple optical carriers from a basic optical carrier; modulating optical carriers, except for a predetermined optical carrier, in the optical carriers by using multiple data signals respectively, to generate multiple optical modulated signals; and synthesizing the multiple optical modulated signals and the predetermined optical carrier into a single optical signal, and transmitting the signal. The reception method comprises separating an optical signal into multiple optical carriers, the optical carriers having different frequencies and including a predetermined optical carrier; generating from the predetermined optical carrier multiple optical waves, frequencies of which correspond to frequencies of optical carriers, except for the predetermined optical carrier, in the multiple optical carriers; and demodulating the optical carriers, except for the predetermined optical carrier, in the multiple optical carriers by using the multiple optical waves respectively.