Pseudo-Return-to-Zero Modulator Using Narrow Pulse Clock
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Solution Overview
Problem
Current Pseudo-Return-to-Zero (PRZ) modulation schemes for optical communications require additional optical modulators, leading to increased size, cost, and signal loss, and are not cost-effective or stable, especially for high-index n values, due to the need for precise control and high-speed digital-to-analog converters.
Innovation Solution
A PRZ modulator is implemented using a narrow pulse clock generator and a modulator driver to generate electrical signals that modulate an optical carrier into a PRZ(n) format, eliminating the need for additional modulators and reducing signal loss, with a configuration that is simple, small-sized, cost-effective, and stable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional optical modulators are used to implement PRZ modulation, then PRZ carving can be achieved, but device complexity and cost increase
Solution Approach 1:
The patent combines the PRZ carving function with the existing optical modulator used for data modulation. Instead of adding a separate modulator, the invention integrates both functions into a single modulator by carefully controlling its drive signals, thereby reducing device complexity and cost while maintaining PRZ modulation performance
Solution Approach 2:
The existing optical modulator is made to perform multiple functions: both data modulation and PRZ carving. By universality principle, the same hardware component (optical modulator) is designed to handle two previously separate tasks, eliminating the need for additional dedicated PRZ carving modulators
2Reliability
If additional optical modulators are used to implement PRZ modulation, then PRZ carving can be achieved, but signal loss increases
Solution Approach 1:
By merging PRZ carving and data modulation into a single optical modulator, the patent eliminates the need for signal to pass through multiple modulators, thereby reducing cumulative insertion loss and improving overall signal quality
3Reliability
If additional optical modulators are used to implement PRZ modulation, then PRZ carving can be achieved, but the apparatus size increases
Solution Approach 1:
The patent reduces apparatus size by combining multiple functional components into a single optical modulator, eliminating the physical space required for additional separate modulators and associated control circuits
4Manufacturing precision
If high-speed digital-to-analog converters are used for precise control, then modulation precision is improved, but cost and complexity increase
Solution Approach 1:
The patent achieves precise modulation control by optimizing the parameters of the drive signals (amplitude, timing, duration) rather than relying on high-speed digital-to-analog converters. This parameter-based approach maintains precision while reducing hardware complexity and cost
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
The solution provides a simple, cost-effective, and stable PRZ carving apparatus that reduces signal loss and power consumption, enabling efficient PRZ modulation without the need for additional modulators, thus improving the quality and tolerance of optical communication signals.
Implementation Method 1
The optical modulator modulates an optical carrier in response to the electrical signal so that the modulated optical carrier is in a PRZ(n) format
Data Source
AI summary
A Pseudo-Return-to-Zero modulator is provided with a narrow pulse clock generator, a modulator driver, and an optical modulator. The narrow pulse clock generator generates a narrow pulse clock of order n, where one of levels occupies half a symbol period and the other level occupies (n−1) plus half a symbol period, n being equal to or more than two. The modulator driver generates an electrical signal in response to binary data and the narrow pulse clock. The optical modulator modulates an optical carrier in response to the electrical signal so that the modulated optical carrier is in a PRZ(n) format.