Electro-Optic Modulator Bias Adjustment via Wavelength Conversion
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Solution Overview
Problem
The existing methods for adjusting the bias voltage of electro-optic modulators in laser devices are complex and cumbersome, requiring high-speed detectors and oscilloscopes to maintain a high extinction ratio, which is time-consuming and inefficient.
Innovation Solution
A method that adjusts the bias voltage of the electro-optic modulator based on the maximum intensity of signal light after wavelength conversion, using a converted light detector to optimize the bias voltage without the need for high-speed detectors or oscilloscopes, by leveraging the change in wavelength conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-speed detectors and oscilloscopes are used to adjust bias voltage, then extinction ratio is maintained high, but device complexity and adjustment difficulty increase
Solution Approach 1:
A bias adjustment detector is introduced as an intermediary device to detect the intensity of converted light. This detector serves as a mediator between the electro-optic modulator and the control system, providing feedback signal for bias voltage adjustment without requiring complex high-speed detection equipment. The detector receives converted light from the wavelength conversion optical element and converts it to electrical signals for control purposes.
Solution Approach 2:
The control device implements feedback control by continuously monitoring the intensity of converted light detected by the bias adjustment detector. When the detected intensity deviates from the optimal value, the control device automatically adjusts the bias voltage to restore optimal conversion efficiency, thereby maintaining high extinction ratio without manual intervention or complex equipment.
2Reliability
If manual bias adjustment procedures are performed, then extinction ratio is optimized, but time consumption and operational complexity increase
Solution Approach 1:
The laser device achieves self-adjustment of bias voltage through automated feedback control. The control device autonomously monitors the converted light intensity via the bias adjustment detector and automatically adjusts the bias voltage without requiring operator intervention. This self-service mechanism eliminates tedious manual adjustment procedures while maintaining optimal extinction ratio.
Solution Approach 2:
The system establishes a closed-loop feedback control mechanism where the control device continuously receives detection results from the bias adjustment detector and automatically modifies the bias voltage accordingly. This automated feedback loop replaces manual adjustment procedures, reducing operational complexity and time consumption while ensuring consistent optimization of extinction ratio.
3Ease of operation
If bias voltage is not properly adjusted, then operational simplicity is maintained, but extinction ratio deteriorates
Solution Approach 1:
The control device implements automatic feedback control that continuously monitors converted light intensity through the bias adjustment detector. When the bias voltage drifts from optimal values, the system automatically detects this deviation and adjusts the voltage to restore optimal performance, thereby maintaining high extinction ratio without requiring manual intervention or complicating the operation.
Solution Approach 2:
The patent replaces manual mechanical adjustment procedures with automated electronic control. The control device uses electronic feedback signals from the bias adjustment detector to automatically adjust the bias voltage, substituting the need for manual observation with oscilloscopes and physical adjustment of components. This automation maintains operational simplicity while ensuring reliable extinction ratio performance.
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 simplifies the bias adjustment process, maintains a high extinction ratio, and ensures clean, short pulses of light are outputted, eliminating the need for complex equipment and procedures.
Implementation Method 1
An electro-optic modulator (EOM: Electro-Optic Modulator) is an optical modulator that utilizes the electro-optic effect of a ferroelectric material such as LiNbO3 (lithium niobate) to modulate and output the phase and amplitude and so on of input light with an electrical signal
Implementation Method 2
a wavelength conversion optical element that wavelength converts the signal light amplified by the optical amplifier
Data Source
AI summary
A laser device includes: a signal light source that outputs seed light; an electro-optic modulator that chops a portion of the seed light outputted from the signal light source and outputs signal light; an optical amplifier that amplifies the signal light outputted from the electro-optic modulator; a wavelength conversion optical element that wavelength converts the signal light amplified by the optical amplifier; a converted light detector that detects the signal light that has been wavelength converted by the wavelength conversion optical element; and an EU control unit that controls the operation of the electro-optic modulator, wherein the EU control unit is adapted, in the state in which the seed light is being outputted, to adjust bias voltage of the electro-optic modulator on the basis of the applied voltage when the intensity of the signal light after wavelength conversion detected by the converted light detector becomes substantially maximum.