DQPSK Light Receiver Merging Interferometers to Reduce Component Count
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Solution Overview
Problem
The existing light receiving apparatus using DQPSK demodulation methods are not suitable for downsizing and low-cost mass production due to the requirement of two sets of optical modules, such as delay interferometers and balanced photoelectric converters.
Innovation Solution
The apparatus employs a Mach-Zehnder interferometer for branching and interfering light signals, a balanced photoelectric converter for converting light intensity differences into electric signals, and a phase adjuster for dynamically shifting the phase of one arm, reducing the number of optical components to one-half compared to traditional configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two sets of optical modules (delay interferometers and balanced photoelectric converters) are used for DQPSK demodulation, then demodulation accuracy is maintained, but apparatus size and manufacturing cost increase
Solution Approach 1:
The patent merges the functions of two delay interferometers into a single Mach-Zehnder interferometer by utilizing both quadrature components of the optical signal. The MZ interferometer processes both in-phase and quadrature components simultaneously through its two arms, eliminating the need for separate delay interferometer modules while maintaining full DQPSK demodulation capability.
Solution Approach 2:
The Mach-Zehnder interferometer is designed to perform multiple functions: it acts as both a delay interferometer for phase differentiation and simultaneously processes both quadrature components for complete DQPSK demodulation. This multi-functional design replaces what previously required two separate specialized modules.
2Reliability
If two sets of optical modules are used for DQPSK demodulation, then demodulation performance is maintained, but manufacturing cost increases
Solution Approach 1:
The patent combines two separate optical module sets into one integrated Mach-Zehnder interferometer system. This reduction in component count directly lowers manufacturing costs by eliminating the need to produce, test, and assemble two complete optical module sets, while the MZ interferometer's inherent design maintains full demodulation performance.
Solution Approach 2:
The patent uses optical copying techniques where the optical signal is split into quadrature components that are processed in parallel within the single MZ interferometer. This allows the system to emulate the functionality of multiple modules through optical signal manipulation rather than physical duplication of hardware.
3Adaptability or versatility
If two sets of optical modules are used for DQPSK demodulation, then complete signal processing is achieved, but apparatus size increases
Solution Approach 1:
The patent merges the spatial footprint of two separate optical module sets into a single compact Mach-Zehnder interferometer. The MZ interferometer's integrated design with shared optical paths and components significantly reduces the overall apparatus area while maintaining the capability to process both quadrature components for complete DQPSK demodulation.
Solution Approach 2:
The patent transitions from a multi-module three-dimensional arrangement to a planar integrated MZ interferometer design. By laying out the optical paths in a two-dimensional plane within the single interferometer structure, the system achieves complete signal processing capability with reduced vertical height and overall footprint.
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 configuration allows for downsizing and cost reduction by using fewer optical components, making the apparatus more suitable for compact and cost-effective manufacturing.
Implementation Method 1
one Mach-Zehnder interferometer for branching a received light signal into light signals at two arms to allow the branched two light signals to interfere with each other
Implementation Method 2
one balanced photoelectric converter for converting the two interfered light signals, by using the Mach-Zehnder interferometer, into an electric signal corresponding to the difference between light intensities of the two light signals
Data Source
AI summary
The present invention provides a light receiving apparatus using the DQPSK demodulation method. The light receiving apparatus comprises: one Mach-Zehnder interferometer for branching a received light signal into light signals at two arms to allow the branched two light signals to interfere with each other; one balanced photoelectric converter for converting the two interfered light signals, by using the Mach-Zehnder interferometer, into an electric signal corresponding to a difference between light intensities of the two light signals; and a phase adjuster for dynamically shifting the phase of a light signal passed through one of the two arms at the Mach-Zehnder interferometer.