Laser Output Coupler Assembly for Frequency Comb Stabilization
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Solution Overview
Problem
Industrial lasers lack the precision and stability needed for quantum computing applications, particularly in terms of frequency comb tuning and phase noise suppression, which affects qubit fidelity and requires advanced control and stabilization of the laser cavity repetition rate.
Innovation Solution
An output coupler assembly with a mounting structure providing multiple degrees of freedom, coupled with a high-bandwidth locking assembly that includes a mirror-piezo actuator combination, mechanically decouples from environmental vibrations and allows for in-situ optimization and stabilization of the frequency comb, using piezo-driven components to adjust the cavity output coupler mirror and suppress phase noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If industrial laser designs are used, then reliability and stability are improved, but manufacturing precision and tuning capability deteriorate
Solution Approach 1:
The laser system is divided into separate functional modules: the main laser cavity for generating pulses, and an independent output coupler assembly with piezo actuation for frequency comb tuning. This segmentation allows the bulk laser to maintain industrial reliability while the isolated output coupler provides precision tuning capability without compromising overall stability.
Solution Approach 2:
A piezoelectric actuator is introduced as an intermediary element between the control system and the output coupler mirror. This intermediary enables fine precision control of the cavity length and frequency comb parameters, translating electrical control signals into precise mechanical adjustments that would be impossible with direct mechanical control alone.
2Adaptability or versatility
If the laser cavity is made adjustable for tuning, then adaptability is improved, but device complexity increases
Solution Approach 1:
Traditional mechanical adjustment mechanisms (screws, levers, manual stages) are replaced with a piezoelectric actuator system. The piezo element converts electrical voltage directly into precise mechanical displacement, eliminating complex mechanical linkages and providing electronic control of the output coupler position, thereby reducing mechanical complexity while enhancing tuning adaptability.
Solution Approach 2:
The system enables tuning by changing the electrical parameters (voltage, frequency) applied to the piezoelectric actuator, which in turn changes the physical parameters (cavity length, mirror position) of the laser. This parameter transformation from electrical to mechanical domain provides a simple control interface for complex tuning requirements.
3Stability of the object's composition
If the output coupler is mechanically coupled to the mount, then structural stability is improved, but phase noise suppression deteriorates
Solution Approach 1:
The piezoelectric actuator and its control electronics are extracted from the main laser structure and housed in a separate, isolated enclosure. This physical separation removes the source of mechanical vibrations and electrical noise from the sensitive laser cavity, preventing these harmful factors from coupling into the optical path and causing phase noise while maintaining overall structural stability.
Solution Approach 2:
The patent employs compliant isolation elements (such as rubber mounts or dampers) at the output coupler assembly to decouple high-frequency vibrations from the main structure. These simple, inexpensive isolation components effectively filter out high-frequency mechanical noise that would otherwise transmit to the cavity and degrade phase 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
Enables precise tuning and stabilization of the frequency comb, minimizing off-resonant coupling and systematics, thereby enhancing the fidelity of quantum information processing and other applications sensitive to laser characteristics.
Implementation Method 1
a piezoelectric actuator coupled to the cavity output coupler mirror
Implementation Method 2
mechanically decouples from environmental vibrations
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
The disclosure describes aspects of laser cavity repetition rate tuning and high-bandwidth stabilization of pulsed lasers. In one aspect, an output optical coupler is described that includes a cavity output coupler mirror, a piezoelectric actuator coupled to the cavity output coupler mirror, a locking assembly within which the cavity output coupler mirror and the piezoelectric actuator are positioned, and one or more components coupled to the locking assembly. The components are configured to provide multiple positional degrees of freedom for tuning a frequency comb spectrum of the pulsed laser (e.g., tuning a repetition rate) by adjusting at least one position of the locking assembly with the cavity output coupler mirror. A method of adjusting an output optical coupler in a pulsed laser is also described. These techniques may be used in different applications, including quantum information processing.