Mutually-Referenced Optical Frequency Combs for Low-Power Synthesis
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Solution Overview
Problem
Current optical synthesizers are limited by size, cost, and power requirements, making them unsuitable for large-scale applications, and micro-resonators struggle to control fine comb tooth spacing while generating wide optical frequency combs.
Innovation Solution
The use of mutually-referenced optical frequency combs, comprising a fine comb with a locked frequency spacing to a radio frequency reference and a coarse comb with a locked spacing to the fine comb, reduces power requirements and achieves stable optical frequency references over a wide tuning range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If self-referenced optical frequency combs based on mode-locked laser sources are used, then accurate and stable optical output over a wide range is achieved, but device size becomes large and power consumption increases
Solution Approach 1:
The invention segments the optical frequency comb into two distinct combs: a first optical frequency comb with fine frequency spacing and a second optical frequency comb with coarse frequency spacing. This segmentation allows each comb to be optimized for different functions, enabling accurate frequency referencing while reducing the power consumption and size associated with generating a single wide-spanning comb.
Solution Approach 2:
The first optical frequency comb acts as an intermediary between the radio frequency reference and the second optical frequency comb. By locking the frequency spacing of the first comb to the radio frequency reference and then locking the second comb to the first comb, the system achieves accurate optical frequency referencing without requiring the second comb to directly span an octave, thereby reducing power requirements.
2Use of energy by stationary object
If micro-resonators are used to generate optical frequency combs, then power consumption is reduced, but control of fine comb tooth spacing while generating wide combs is not achieved
Solution Approach 1:
The invention segments the frequency comb generation into two separate micro-resonator-based combs with different spacing characteristics. The first comb provides fine frequency spacing suitable for precise control and referencing, while the second comb provides wide frequency coverage. This segmentation enables both fine spacing control and wide bandwidth without requiring excessive power input.
Solution Approach 2:
The invention adds a hierarchical dimension to the frequency comb structure by introducing two different frequency spacing scales (fine and coarse). This dimensional approach allows the system to achieve both precise frequency control and wide optical bandwidth simultaneously, overcoming the limitation of single-scale comb generation in micro-resonators.
3Adaptability or versatility
If a single wide-spanning optical frequency comb is generated, then wide tuning range is achieved, but fine comb tooth spacing control becomes difficult
Solution Approach 1:
The invention divides the wide-spanning frequency comb into two separate combs: one optimized for fine frequency spacing with high precision control, and another optimized for wide frequency coverage. This segmentation allows each comb to maintain its respective strengths, achieving both wide tuning range and precise tooth spacing control.
Solution Approach 2:
The invention introduces a hierarchical frequency spacing structure with two dimensions: fine spacing for precision and coarse spacing for wide coverage. This multi-dimensional approach enables the system to achieve both wide optical bandwidth and precise frequency control, which cannot be accomplished with a single uniform comb structure.
Data Source
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AI summary
Embodiments herein provide for an optical frequency reference including a fine optical frequency comb and a coarse optical frequency comb. The fine comb has a first tooth and a frequency spacing (FCS) between teeth that is locked to a fractional or integer multiple of a radio frequency reference. The coarse comb has a second tooth that is locked to the first tooth and a frequency spacing (CCS) between teeth that is locked to an integer multiple of the FCS. An absolute optical frequency of at least one tooth of the coarse optical frequency comb is set.