Optical Transmitter Drive Timing Control
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Solution Overview
Problem
Existing optical transmitters face challenges in accurately adjusting the timing of drive signals to phase-shift segments in optical modulators, particularly under temperature changes and voltage fluctuations, leading to waveform deterioration and reduced optical signal quality.
Innovation Solution
An optical transmitter system that includes a signal processing circuit generating drive signals for a Mach-Zehnder interferometer with multiple phase-shift segments, an optical filter to remove specific frequency components, and a delay circuit controlled by a power monitor to optimize the timing of drive signals, minimizing power loss and improving signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the timing of drive signals to phase-shift segments is manually adjusted, then initial signal quality can be achieved, but the system cannot adapt to temperature changes and voltage fluctuations causing waveform deterioration
Solution Approach 1:
The patent implements an automatic timing adjustment mechanism that uses feedback from signal quality detection. A signal quality detection unit monitors the optical signal characteristics, and when waveform deterioration is detected due to temperature or voltage changes, the system automatically adjusts the timing of drive signals to phase-shift segments to restore optimal signal quality, eliminating the need for manual readjustment and providing continuous adaptation to environmental changes.
2Use of energy by moving object
If multiple phase-shift segments are used to reduce power consumption, then binary drivers can be used with lower current, but accurate timing synchronization becomes more complex
Solution Approach 1:
The system employs self-service through automatic timing adjustment. The signal quality detection unit continuously monitors the optical output and automatically controls the timing of drive signals to multiple phase-shift segments without external intervention. This self-adjusting mechanism simplifies the overall system by eliminating the need for complex manual synchronization procedures while maintaining low power consumption benefits of binary drivers.
3Measurement precision
If manual timing adjustment is performed, then initial optimization can be achieved, but continuous adaptation to varying conditions requires repeated manual intervention
Solution Approach 1:
The patent ensures continuous optimization of signal quality through automatic timing adjustment. The signal quality detection unit operates continuously to monitor optical signal characteristics, and the timing control unit continuously adjusts drive signal timing in response to detected changes. This continuous automatic adjustment eliminates the need for repeated manual interventions, maintaining optimal signal quality throughout operation without time loss to manual readjustment.
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 system effectively adjusts drive signal timings to maximize optical power and optimize the quality of the modulated optical signal, even under varying conditions, by using a power monitor to control the delay circuit and an optical filter to manage frequency components, thereby enhancing the eye pattern opening and signal integrity.
Implementation Method 1
an optical modulator that includes a Mach-Zehnder interferometer... when an output signal of a driver is provided to the electrode, a phase of light propagating through the waveguide changes according to the signal
Implementation Method 2
an optical modulator includes an electrode with respect to each of a plurality of bits transmitted by each symbol... an electrode is formed in the vicinity of the optical waveguide
Data Source
AI summary
Optical transmitter includes: signal processing circuit, optical modulator, optical filter, and delay circuit. The signal processing circuit generates N drive signals for generating a modulated optical signal. Symbol rate of the modulated optical signal is fs and each symbol of the modulated optical signal transmits N bits. The optical modulator includes Mach-Zehnder interferometer and N phase-shift segments each of which shifts a phase of light propagating through an optical path of the Mach-Zehnder interferometer according to the N drive signals. The optical filter removes, from output light of the optical modulator, a frequency component in a range of ±fs/2 with respect to a center frequency of the modulated optical signal, and extracts at least a part of other frequency components. The delay circuit controls timings of the N drive signals so as to reduce optical power of the frequency component extracted by the optical filter.