Multiple Channel Fiber Pigtailed Acousto-Optic Device
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Solution Overview
Problem
Commercially available Acousto-Optic Modulators (AOMs) cannot meet the requirement for rise/fall time less than 5-6 ns needed for high repetition frequency lasers, and they have high AO material costs and low diffraction efficiency due to short optical paths.
Innovation Solution
A multiple channel fiber pigtailed acousto-optic device is developed, comprising multiple input and output fibers with an acousto-optic modulator in between, where output fibers are coupled to input fibers to reduce rise/fall time while maintaining the same cost as single AOMs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the optical path in the AO crystal is shortened to reduce rise/fall time, then the rise/fall time is improved, but the diffraction efficiency deteriorates and the AO material cost increases
Solution Approach 1:
The invention divides the optical path into multiple segments by using multiple AOMs in series, each processing a portion of the total optical path. This segmentation allows each individual AOM to have a shorter crystal length (improving rise/fall time) while the cumulative effect of multiple stages maintains the total diffraction efficiency required for the system.
Solution Approach 2:
The invention combines multiple AOMs in series to achieve the cumulative diffraction efficiency of a single long-crystal AOM, while each individual AOM maintains a short crystal length for fast response. The merging of multiple short-crystal AOMs effectively replaces one long-crystal AOM, resolving the contradiction between speed and efficiency.
2Speed
If multiple AOMs are used in series to reduce rise/fall time, then the rise/fall time is improved, but the device complexity and cost increase
Solution Approach 1:
Each AOM in the series is designed to perform the same function (acousto-optic modulation) with identical or similar specifications. This universality allows for standardized components that can be mass-produced, reducing individual unit costs and simplifying the overall system design despite the increased number of components.
Solution Approach 2:
The invention uses identical copies of the same AOM design multiple times in series. By replicating a proven, optimized AOM design rather than creating a single complex high-performance AOM, the system achieves the desired performance while benefiting from the economies of scale and manufacturing simplicity of producing multiple identical units.
3Speed
If the optical path is shortened to meet 20-80 MHz repetition frequency requirements, then the speed is improved, but the AO material cost increases
Solution Approach 1:
The total required diffraction efficiency is segmented across multiple AOMs, each using a small amount of AO material with short crystal length. This segmentation reduces the total quantity of expensive AO material required compared to a single long-crystal AOM, while achieving the same cumulative effect and meeting the high repetition frequency requirements.
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 device achieves shorter rise/fall time than single AOMs without increasing costs, by using fiber coupling to reduce the acoustic traveling time, thus enhancing performance for high-frequency laser applications.
Implementation Method 1
A piezoelectric transducer is attached to an acousto-optic (AO) material such as glass, quartz, or other crystals. An oscillating electric signal drives the transducer to vibrate, which creates sound waves in the AO material.
Implementation Method 2
By vibrating the material with a pure sinusoid so that the light is diffracted into the first diffraction order, very high diffraction efficiency can be achieved.
Data Source
AI summary
A multiple channel fiber pigtailed acousto-optic (AO) device comprises: a first multiple fiber collimator pigtail comprising a plurality of input fibers, a second multiple fiber collimator pigtail comprising a plurality of output fibers, wherein each of the plurality of output fibers is a conjugate of each of the plurality of input fibers, respectively, and an acousto-optic modulator (AOM) disposed between the first multiple fiber collimator pigtail and the second multiple fiber collimator pigtail, wherein the input fibers form input ports providing input beams to the AOM and the output fibers form output ports receiving output beams from the AOM, wherein at least one output fiber of the plurality of output fibers is coupled to an input fiber of the plurality of input fibers.