Laser Diode Pumped Solid-State Laser Oscillator with Bypass Circuit Control
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Solution Overview
Problem
In LD-pumped solid-state laser oscillators, failures of laser diodes lead to uneven pumping distribution and pointing deviations, resulting in reduced laser output and efficiency, which cannot be adequately restored by simply reallocating power, and increasing the energizing current shortens the diode's lifetime and is costly due to the need for additional diodes.
Innovation Solution
An LD-pumped solid-state laser oscillator with detection and control systems that identify failed diodes and adjust the supply currents to other diodes based on their position, using bypass circuits to maintain efficient pumping distribution and reduce the need for increased energizing current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the energizing current is increased to compensate for LD failure and restore laser output, then the laser output is restored, but the LD lifetime is shortened
Solution Approach 1:
The patent applies local quality by adjusting the energizing current of individual LDs based on their specific position and failure status. When an LD fails, the system selectively increases current to specific neighboring LDs rather than uniformly increasing current to all LDs, optimizing both power restoration and lifetime preservation.
Solution Approach 2:
The system dynamically changes the energizing current parameter of LDs based on real-time monitoring of LD status and position. By calculating optimal current values for each LD based on its position relative to failed LDs, the system restores laser output while minimizing the increase in energizing current to extend LD lifetime.
2Power
If the energizing current is increased to compensate for LD failure, then the laser output is restored, but the power consumption increases
Solution Approach 1:
The patent implements local quality by applying energy compensation locally to specific LDs near the failure point rather than increasing power to the entire LD array. This localized approach restores laser output while minimizing overall power consumption increase.
Solution Approach 2:
The system applies partial action by increasing current only to the extent necessary for specific LDs to compensate for the failed LD's contribution. Rather than uniformly increasing current to all LDs beyond normal levels, the system applies just enough additional current to affected areas to restore output.
3Reliability
If a bypass circuit is provided for each LD to prevent oscillator stoppage, then the oscillator reliability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent applies universality by using a single detection circuit that can identify failures in any LD within the array, and a centralized control unit that manages current adjustment for multiple LDs. This multi-functional approach provides comprehensive failure protection without requiring separate bypass circuits for each LD, reducing overall system complexity.
Solution Approach 2:
The system merges the detection and control functions into integrated units that manage multiple LDs collectively. By combining these functions at the system level rather than implementing separate protection circuits for each LD, the patent reduces device complexity while maintaining high reliability.
4Power
If the LDs are arranged in series to achieve high laser output, then the laser output is increased, but the system becomes vulnerable to complete failure from a single LD open failure
Solution Approach 1:
The patent implements feedback through detection circuits that continuously monitor each LD's status and provide real-time information to the control unit. When an LD fails in a series configuration, the feedback mechanism enables the control unit to detect the failure and redistribute current to maintain laser output, preventing complete system failure and improving reliability.
Solution Approach 2:
The system applies dynamics by enabling flexible current redistribution among LDs based on real-time status changes. When an LD fails in a series arrangement, the system dynamically adjusts current paths and magnitudes to affected LDs, allowing the series configuration to maintain high output while adapting to failure conditions to preserve reliability.
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 suppresses the increase in energizing current required to maintain laser output, corrects uneven pumping, and extends the lifetime of diodes while reducing power consumption and costs by optimizing the distribution of power and diode usage.
Implementation Method 1
a plurality of laser diodes 6 arranged around the solid-state pumping medium 7 and adapted to irradiate pumping light 22 to the solid-state pumping medium 7
Implementation Method 2
a solid-state laser oscillator having the functions of preventing the laser oscillator from stopping due to the failure of a laser diode
Data Source
AI summary
Plural LDs 6 are series-connected and pump a solid-state pumping medium 7. Each of bypass circuits 15 is connected in parallel to an associated one of the LDs 6. An operation of driving each of the bypass circuits 15 is controlled by a control circuit 14. A detection circuit 13 is provided corresponding to each of the LDs 6 and detects a short circuit failure and an open failure of each of the LDs 6 according to a voltage developed thereacross or the like. The detection circuit 13 and the control circuit 14 are connected to and are controlled by an LD shortcircuit control circuit 11. In a case where a failure of the LD is detected by the detection circuit 13, the LD shortcircuit control unit 11 determines the position of the failed LD to bypass electric current having flowed through the failed LD. Then, the control circuit 11 sends a signal to a predetermined control circuit 14 to thereby operate a predetermined bypass circuit 15. The LD shortcircuit control unit 11 determines the position of the LD, which is to be turned off, according to the position of the failed LD to improve a pointing deviation in the solid-state medium 7. Then, the control unit 11 sends a signal to the control circuit 14 to turn off this LD. Thus, the control unit 11 causes a predetermined bypass circuit 15 to operate thereby to turn off the predetermined LD.