Optical Fiber Laser Damage Prevention via Beam Attenuation
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Solution Overview
Problem
Optical fibers used in laser energy delivery systems often suffer damage due to high initial pulse energies and unstable beam quality, leading to premature failure when bent at or near the minimum bend radius, causing energy loss and potential harm during surgical procedures like ureteroscopic laser lithotripsy.
Innovation Solution
Implementing a beam attenuation process that temporarily reduces the laser beam's power during the initial unstable emission period, using a combination of beam attenuators and controllers to adjust the attenuation, and potentially blocking the pump source's emission to prevent damage to the optical fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power laser output is delivered through optical fiber at minimum bend radius, then surgical effectiveness is improved, but fiber damage occurs leading to premature failure
Solution Approach 1:
The patent applies preliminary action by blocking the initial unstable laser emissions before they can reach and damage the optical fiber. A beam block is positioned in the beam path to prevent the high energy initial pulses from coupling into the fiber, allowing the laser to stabilize first. This resolves the contradiction by protecting the fiber (improving reliability) while still enabling subsequent high power delivery (maintaining surgical effectiveness).
Solution Approach 2:
The patent applies preliminary anti-action by introducing a counter-action (beam blocking) to offset the harmful effect of initial unstable emissions. The beam block temporarily counteracts the laser output during the unstable period, preventing the harmful coupling to the fiber. After stabilization, the block is removed to allow full power delivery, thus resolving the contradiction between power delivery and fiber protection.
2Reliability
If beam attenuation is applied during initial emissions, then fiber damage is prevented, but laser power delivery is reduced temporarily
Solution Approach 1:
The patent applies periodic action by temporarily blocking the laser beam during the initial unstable emission period, then removing the block once stabilization occurs. This periodic blocking strategy protects the fiber during the critical initial phase while allowing full power delivery during the stable operational phase, thus resolving the contradiction between fiber protection and power delivery.
Solution Approach 2:
The beam block is applied preliminarily during the unstable emission period before full power delivery begins. This preliminary attenuation protects the fiber from damage while the laser stabilizes, and is subsequently removed to enable full power output, resolving the contradiction between protection and power delivery.
3Adaptability or versatility
If minimum bend radius is exceeded to navigate tortuous anatomy, then access to kidney stones is improved, but fiber burn through occurs
Solution Approach 1:
The patent applies preliminary anti-action by blocking the initial high energy emissions before they can cause burn damage to the fiber at tight bends. The beam block prevents the harmful thermal effect that would otherwise occur when unstable emissions couple into the fiber at minimum bend radius, enabling safe navigation through tortuous anatomy.
Solution Approach 2:
The beam block is applied preliminarily to prevent the conditions that would lead to burn damage. By blocking initial emissions before fiber insertion or before full power delivery, the system enables the fiber to be safely positioned at minimum bend radius without subsequent burn through, thus resolving the contradiction between navigation flexibility and fiber safety.
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 prevents premature failure of optical fibers by reducing damage from high initial pulse energies and unstable beam quality, allowing safer and more effective delivery of laser energy through tight bends, thereby reducing costly repairs and minimizing the risk of injury to patients and equipment.
Implementation Method 1
attenuating the beam reaching the optical fiber for a period of time (T1) from the initiation time
Data Source
AI summary
Optical fibers for delivering laser energy inside the body are often tasked with traversing tortuous routes in accessing the target tissue or pathology, e.g. ureteroscopic laser lithotripsy. A common failure in such applications, known in the field as ‘fiber burn through’, has been known to injure patients and is a major cause of damage to ureteroscopes. Where irregular output that is produced at the start of a lasing interval passes through a fiber that is at or near the optical minimum bend limit, fail safe polymer claddings are damaged and can no longer contain even regular laser output in tight deflection. The invention disclosed provides a solution to premature fiber failure and collateral damage.