External Resonator Laser Diode Assembly for Mode-Hop-Free Tuning
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Solution Overview
Problem
Existing laser diode arrangements with external resonators suffer from high manufacturing costs, low resonance frequency, and high sensitivity to interferences, making them inefficient for mode jump-free tuning of laser wavelengths.
Innovation Solution
A laser diode arrangement with an external resonator featuring a rotatable resonator mirror and a wavelength selective optical reflection element, where the resonator mirror is supported for rotation about a pivot axis and is pivotable by a deflection device, allowing for mode jump-free tuning of the laser wavelength without the need for expensive MEMS actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a MEMS actuator is used to pivot the resonator mirror for mode jump-free tuning, then the laser wavelength can be tuned continuously without mode jumps, but the manufacturing cost increases significantly and the resonance frequency decreases
Solution Approach 1:
The patent extracts the resonator mirror from the conventional fixed position and makes it independently pivotable about a pivot axis, separating its tuning function from the expensive MEMS actuator system. This allows the mirror to be adjusted by simpler, lower-cost mechanical means while maintaining mode jump-free tuning capability.
Solution Approach 2:
The resonator mirror is designed to be dynamically pivotable about a pivot axis, allowing continuous adjustment of the optical path length and wavelength selection. This dynamic configuration enables mode jump-free tuning without requiring complex MEMS actuation mechanisms.
2Ease of operation
If a MEMS actuator is used to pivot the resonator mirror, then the laser wavelength can be tuned continuously, but the resonance frequency decreases and sensitivity to interferences increases
Solution Approach 1:
The patent replaces the MEMS actuator mechanical system with a simpler pivot-based mechanical system for the resonator mirror. This substitution eliminates the low resonance frequency issue inherent in MEMS actuators and reduces sensitivity to external interferences while maintaining continuous tuning capability.
3Ease of manufacture
If the resonator mirror is made rotatable about a pivot axis with a deflection device, then manufacturing costs are reduced and resonance frequency is increased, but the device complexity increases
Solution Approach 1:
The resonator mirror serves multiple functions: it reflects the laser beam, enables wavelength selection, and provides continuous tuning capability through pivoting. This multi-functionality is achieved with a single component rather than multiple separate elements, reducing overall device complexity despite the added pivoting capability.
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 design reduces manufacturing costs, increases resonance frequency, and decreases sensitivity to interferences, enabling continuous, mode jump-free tuning of the laser wavelength over a large frequency range.
Implementation Method 1
a laser beam emitted by the laser diode into the external resonator with a first incident angle depending on the pivot position of the resonator mirror and hitting a mirror surface of the resonator mirror and is reflected therefrom onto the at least one wavelength selective optical reflection element
Implementation Method 2
at least one wavelength selective optical reflection element with a diffracting surface wherein the resonator mirror is supported so as to be rotatable about a pivot axis
Data Source
AI summary
The invention relates to a laser diode assembly for producing single-mode, tunable laser radiation. The laser diode assembly comprises a laser diode (4) and an external resonator (10), which is coupled thereto and comprises a resonator mirror (12) and a wavelength-selective optical reflective element (14) having a diffractive surface. The resonator mirror is mounted for rotation about a pivot axis (16) and can be selectively rotated about the pivot axis by means of a deflecting device. The external resonator is designed such that a laser beam emitted from the laser diode into the external resonator impinges on a mirror surface (30) of the resonator mirror (12) at a first angle of incidence, which is dependent on the rotation of the resonator mirror, and is reflected by the resonator mirror onto the at least one wavelength-selective optical reflective element at a second angle of incidence, which is dependent on the first angle of incidence, an optical distance (d) between the resonator mirror and the diffractive surface (20) being influenced by the first angle of incidence (γ), and that the wavelength-selective optical reflective element reflects the laser beam, so as to be diffracted, back to the resonator mirror. The wavelength of the laser beam reflected by the wavelength-selective reflective element is influenced by the second angle of incidence (φ).