Tunable Diode Laser Flexure Joint Inversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tunable diode laser systems in Littrow and Littman configurations face challenges in achieving mode-hop-free tunability due to complex mechanisms and high sensitivity to mechanical vibrations, requiring precise control of multiple actuators and complex electronics, which increases production costs and makes the systems difficult to maintain.
Innovation Solution
A tunable diode laser system with an external resonator using flexure joints to precisely define the center of rotation, allowing for single-actuator control and a compact design that reduces sensitivity to vibrations, featuring a carrier connected to a base body via flexure joints that convert linear deflection into rotary movement, enabling precise and reproducible tuning without mode hopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a long rotating arm is used to rotate the diffraction grating about the correct center of rotation, then the wavelength can be tuned without mode hopping, but the system becomes very large and sensitive to mechanical vibrations
Solution Approach 1:
Instead of rotating the grating about an external center of rotation using a long arm, the invention inverts the approach by having the grating rotate about its own center while the entire holding element rotates about the required center of rotation. This is achieved by coupling the grating to the holding element through flexure joints that allow relative rotation. The inversion eliminates the need for a long rotating arm while maintaining mode-hop-free tuning and reducing vibration sensitivity.
Solution Approach 2:
The system is segmented into independent rotational degrees of freedom: the grating can rotate independently about its center relative to the holding element, while the holding element itself rotates about the center of rotation defined by the laser cavity geometry. This segmentation allows each component to perform its function optimally without requiring a mechanically complex and vibration-sensitive long arm structure.
2Manufacturing precision
If multiple piezo actuators are used to control grating rotation and resonator length synchronously, then mode-hop-free tunability is achieved, but the system complexity and manufacturing cost increase
Solution Approach 1:
The invention merges the control functions into a single actuator that rotates the entire holding element about the center of rotation. The grating's rotation about its own center is achieved passively through the flexure joint coupling, eliminating the need for a second actuator. This combining of functions reduces device complexity and manufacturing cost while maintaining mode-hop-free tunability.
Solution Approach 2:
The flexure joint enables the grating to rotate about its center automatically as the holding element rotates, without requiring active control or an additional actuator. The mechanical coupling through the flexure joint provides self-service rotation that synchronizes with the holding element's movement, simplifying the control system.
3Manufacturing precision
If the diffraction grating is rotated about a center of rotation defined by the intersection of multiple planes, then wavelength tuning without mode hopping is achieved, but the mechanism becomes very complex and expensive to manufacture
Solution Approach 1:
The invention inverts the traditional approach by having the holding element rotate about the pre-defined center of rotation (intersection of the three planes) rather than trying to mechanically enforce this complex rotation point directly on the grating. The grating rotates independently about its own center, and the flexure joint coupling ensures the correct geometric relationship is maintained, greatly simplifying manufacturing.
4Manufacturing precision
If a long rotary arm is used to achieve the correct rotation, then mode-hop-free tuning is possible, but the system becomes difficult to control thermally and prone to maladjustment during transport
Solution Approach 1:
The invention inverts the mechanical arrangement by eliminating the long rotary arm and instead having compact components rotate about their own centers with coupling through flexure joints. This dramatically reduces the mechanical lever arms and structural complexity, making the system much more resistant to thermal expansion effects and mechanical shocks during transport, while maintaining tuning stability.
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 achieves reliable mode-hop-free tunability with reduced mechanical sensitivity and lower production costs, ensuring long-term stability and ease of maintenance by using a single actuator and elastic flexure joints that minimize wear and thermal drift.
Implementation Method 1
an optical grating on which the light beam of a laser diode is diffracted
Implementation Method 2
the feedback is provided via the end facet of the laser diode
Implementation Method 3
flexure joints that convert linear deflection into rotary movement
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
The tunable diode laser system comprises an optical lattice (7), where the ray of light (16) of a laser diode (4) is diffracted. A retaining element (6) has a carrier (11) at which the optical lattice is arranged. A base (9) is provided, where an actuator (12), supported at the carrier, affects the carrier. The carrier is connected with the base by joints (13,14).