Optical Reception Device Using Electronic Signal Equalization
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Solution Overview
Problem
Optical reception devices using DPSK demodulation methods are expensive and unsuitable for size reduction due to complex configurations and manufacturing processes that hinder mass production and integration, similar to semiconductor integrated circuits.
Innovation Solution
The optical reception device employs electronic circuits for amplitude and delay adjustments post-DPSK demodulation, eliminating the need for optical components and enabling integration, which allows for independent setting of amplification factors and delay times to equalize electrical signal amplitudes and phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical components (delay adjusters and variable attenuators) are used for DPSK demodulation, then reception sensitivity is improved, but device cost and complexity increase
Solution Approach 1:
The patent replaces optical components (delay adjusters and variable attenuators) with electronic circuits that perform the same functions. The electronic delay adjuster and electronic variable attenuator substitute for the optical components, enabling DPSK demodulation while reducing device complexity and cost.
Solution Approach 2:
The patent changes the domain of operation from optical to electronic by converting optical signals to electrical signals before processing. This parameter change allows the use of electronic components instead of optical components, resolving the contradiction between reception sensitivity and device complexity.
2Reliability
If optical components are assembled for DPSK demodulation, then reception performance is improved, but manufacturing cost increases due to lack of mass production suitability
Solution Approach 1:
The patent replaces optical components with electronic circuits that can be manufactured using standard semiconductor fabrication processes. This substitution enables mass production and reduces manufacturing cost while maintaining reception performance.
Solution Approach 2:
The electronic circuits designed in the patent can be integrated into semiconductor chips, making them suitable for mass production. The universal applicability of electronic circuit fabrication processes allows for cost reduction through economies of scale.
3Adaptability or versatility
If optical components are used for signal adjustment, then signal processing capability is improved, but device size cannot be reduced
Solution Approach 1:
The patent replaces bulky optical components with compact electronic circuits that can be integrated into semiconductor chips. This substitution dramatically reduces device size while maintaining signal processing capability for DPSK demodulation.
Solution Approach 2:
The electronic circuits are designed to be integrated within semiconductor chips, nesting multiple functions within a single compact package. This integration approach enables significant size reduction compared to discrete optical components.
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 reduces the cost and size of the optical reception device by leveraging electric circuits suitable for mass production and integration, thereby enhancing cost-effectiveness and miniaturization.
Implementation Method 1
optical-electrical signal converter (dual PD (photo-detector)) 209 is for converting optical signals 207 and 208 into an electrical signal
Data Source
AI summary
The present invention converts each of the optical differential signals from DPSK demodulator from an optical signal into an electrical signal by using optical-electrical signal converters. Thereafter, each electrical signal is subjected to amplification adjustment at an appropriate amplification factor by variable amplifier, and an appropriate delay amount is added to each electrical signal by variable delay line, and thereafter data discrimination is performed by discriminator. Since two differential signals after DPSK demodulation are subjected to amplitude and delay adjustments, the need for optical parts is obviated enabling the use of electric circuits which can be integrated. Thus, the cost of the optical reception device will be reduced. Moreover, the since electric signals whose phases and amplitudes are equalized are inputted to discriminator, erroneous determination of data at discriminator will be reduced.