Piezoelectric Tuned Laser Flex Bearing Pivot
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Solution Overview
Problem
Existing tunable external-cavity diode lasers face challenges in achieving continuous mode-hop-free tuning, require improved rotational axis control, and are not suitable for harsh or vacuum environments due to instability and potential outgassing issues with glue.
Innovation Solution
A laser tuning apparatus with a base and a fine tuning arm secured for rotation about a pivot axis, utilizing a piezoelectric transducer and a flexible bearing to provide stable and continuous wavelength tuning, eliminating mode hops and suitable for harsh and vacuum environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric actuator is used to rotate the end mirror for tuning, then wavelength selectivity and continuous tuning are achieved, but the rotational axis control is insufficient and mode hops occur
Solution Approach 1:
A flex bearing is introduced as an intermediary component between the piezoelectric actuator and the end mirror. The flex bearing provides a precisely defined pivot axis that acts as a mediator, translating the linear motion of the piezoelectric actuator into controlled rotational motion of the end mirror about a fixed axis, thereby eliminating mode hops while maintaining wavelength tuning precision
Solution Approach 2:
The invention changes the physical state and motion parameters of the tuning mechanism by defining a fixed pivot axis through the flex bearing. This parameter change ensures that the end mirror rotates about a precisely controlled axis rather than an undefined torsional axis, enabling continuous mode-hop-free tuning across the desired wavelength range
2Ease of manufacture
If glue is used to secure components in the laser housing, then assembly is simplified, but outgassing occurs in vacuum environments
Solution Approach 1:
The harmful element (glue) is completely removed from the laser housing assembly. Components are secured using mechanical fastening methods such as screws or interference fits, which do not involve organic adhesives that would outgas in vacuum environments, thereby eliminating the harmful effect while maintaining assembly integrity
Solution Approach 2:
The invention creates an inert environment-compatible design by selecting materials and assembly methods that are suitable for vacuum conditions. All securing mechanisms and structural components are chosen to be vacuum-compatible, ensuring no outgassing occurs in the harsh vacuum environment of outer space
3Device complexity
If a torsional member defines the rotational axis, then the structure is simple, but the rotational axis control is poor and tuning stability is reduced
Solution Approach 1:
The flex bearing serves as a precision intermediary that replaces the simple torsional member. It provides a well-defined pivot axis with controlled rotational stiffness, acting as a mediator between the simple structural requirement and the precise rotational axis control needed for stable laser tuning
Solution Approach 2:
The flex bearing introduces dynamic characteristics to the tuning mechanism by providing controlled rotational compliance in the pivot axis. This dynamic property allows the system to maintain precise rotational control while accommodating thermal and mechanical variations, improving tuning stability without excessive structural complexity
4Ease of manufacture
If the laser is designed for terrestrial environments, then manufacturing and operation are easier, but it is not suitable for harsh environments like outer space
Solution Approach 1:
The laser design is adapted for inert vacuum environments by eliminating all vacuum-incompatible materials and components. The housing, fasteners, and internal components are selected to be vacuum-compatible with no outgassing, enabling the laser to operate in harsh environments like outer space while maintaining terrestrial manufacturing capabilities
Solution Approach 2:
The invention creates a universal laser design that can operate in multiple environments (both terrestrial and space vacuum). By using environment-independent materials and assembly methods, the laser achieves multi-functionality, adapting to harsh environments without sacrificing manufacturing ease or 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
Enables reliable, accurate, and controllable rotation for continuous wavelength tuning without mode hops, even in extreme environments like outer space, with fine increment control and improved stability.
Implementation Method 1
A piezoelectric transducer is coupled to a flex bearing so as to allow stable movement of the tuning reflector
Implementation Method 2
a flex bearing so as to allow stable movement of the tuning reflector, or the feedback prism
Implementation Method 3
a diffraction grating at grazing incidence, together with a tuning reflector, to provide wavelength selectivity
Implementation Method 4
The end mirror of the laser cavity reflects the first-order diffraction off the grating to provide feedback
Data Source
AI summary
A tunable laser comprising: a foundation including a first side and an oppositely facing second side and including a hole extending from the first side to the second side; a tuning assembly including a base, a fine tuning arm and a rotational flex bearing disposed adjacent the first side of the foundation; wherein the base is disposed adjacent to the first side of the foundation; wherein one end of the flex bearing is secured to the base; wherein the other end of the flex bearing is secured to the fine tuning arm; wherein a portion of the fine tuning arm extends at least partially into the hole; an external cavity laser including a gain medium, a dispersion medium and a reflective member disposed adjacent to the second side of the foundation; wherein the gain medium and the dispersion medium grating are secured in a fixed relation relative to the each other; wherein the reflective member is secured to the portion of the arm extending into the hole; and a piezoelectric device with one end secured to the base and another end secured to the arm.