Optical Modulation Timing Adjustment Using Test Patterns
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical modulation techniques, such as those using Mach-Zehnder optical modulation apparatus, face challenges in accurately adjusting modulation timing between data strings, particularly when the timing difference exceeds one cycle of a bit, leading to degraded signal properties.
Innovation Solution
An optical modulation apparatus that includes a laser light source, branch, optical modulators, a timing adjuster, and a phase adjuster, which uses test data signals with alternating marks and spaces to adjust modulation timing based on intensity detection, ensuring proper phase alignment and timing synchronization between modulated light beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light intensity detector is disposed to detect the intensity of the synthesized light beam for timing control, then the timing difference between data strings can be compensated, but the technique fails to compensate timing differences equal to or more than one cycle of bit (multi-bit difference)
Solution Approach 1:
The patent applies preliminary action by using test data signals with known patterns (alternating marks and spaces) before normal data transmission. The timing adjustment is performed in advance using these test signals, allowing the system to establish proper synchronization before actual communication begins. This preliminary timing calibration ensures that multi-bit timing differences can be detected and corrected before they affect real data transmission.
Solution Approach 2:
The patent changes the parameter being measured from simple light intensity to light intensity variations over time using test patterns. By using test data signals with alternating marks and spaces, the system can detect timing differences by analyzing how the light intensity varies across multiple bit cycles. This parameter change enables the detection of multi-bit timing offsets that would be invisible using conventional intensity-only detection.
2Ease of operation
If the distance from the data generator to the optical modulator varies between data strings, then timing differences occur between modulated data strings, but no effective compensation method exists for multi-bit timing differences
Solution Approach 1:
The patent implements feedback by using the detected light intensity variations from test patterns to adjust the timing of subsequent data transmission. The system continuously monitors the timing relationship between I and Q data strings using the test signal feedback, and automatically adjusts the modulation timing to maintain synchronization. This closed-loop feedback mechanism ensures that timing precision is maintained even when physical distances vary between data paths.
Solution Approach 2:
The patent introduces test data signals as an intermediary element to facilitate timing adjustment. These test signals with known alternating patterns serve as a mediator between the variable physical paths and the timing control mechanism. By using this intermediary test signal, the system can indirectly measure and compensate for timing differences caused by varying distances without directly measuring the physical path lengths.
3Reliability
If conventional timing adjustment methods are used, then single-bit timing differences can be compensated, but multi-bit timing differences cause signal property degradation
Solution Approach 1:
The patent applies periodic action by using test data signals with regular alternating patterns of marks and spaces. This periodic structure creates predictable, repeating light intensity variations that make it easier to detect timing offsets. By using periodic test signals rather than random or single-pattern signals, the system can identify multi-bit timing differences through the regular rhythm of the alternating pattern, enabling compensation without significantly increasing device complexity.
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 effectively adjusts modulation timing to minimize signal degradation, accurately compensating for timing differences greater than one bit, thereby enhancing signal quality and consistency.
Implementation Method 1
a light intensity detector detecting the intensity of the synthesized light beam
Implementation Method 2
a first optical modulator modulating the first light beam on the basis of the first data signal; a second optical modulator modulating the second light beam on the basis of the second data signal
Data Source
AI summary
An optical modulation apparatus that can adjust modulation timing. A timing adjuster adjusts the modulation timing on the basis of an intensity detected by a light intensity detector, after a data generator respectively generates, as a first data signal and a second data signal, a first test data signal and a second test data signal each having a data string containing a test pattern in which a plurality of continuous marks and a plurality of continuous spaces are alternately repeated, and after a phase adjuster adjusts a phase difference to zero or π.