Compact Wavelength Meter Using Tunable Interferometers
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Solution Overview
Problem
Conventional wavelength meters are large, rugged, and unsuitable for high-repetition-rate lasers with agile output waveforms, limiting their measurement capabilities to below 1000 measurements per second and 500 Hz continuous tuning bandwidth, and struggle with precise wavelength determination in applications requiring high accuracy and speed.
Innovation Solution
A compact photonic integrated circuit (PIC)-based interferometer with multiple tunable interferometers of different free spectral ranges (FSRs), capable of measuring optical wavelengths with high precision and speed, includes an optical splitter, detectors, and a phase modulation spectroscopy path to correct for environmental variations, allowing for unambiguous wavelength measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional wavelength meters are used, then measurement accuracy is sufficient for typical applications, but device size becomes large and measurement speed is limited to below 1000 measurements per second
Solution Approach 1:
The patent replaces conventional mechanical/optical wavelength meter components with a photonic integrated circuit (PIC) system. The PIC integrates multiple interferometers, waveguides, and detectors on a single chip, substituting bulky mechanical assemblies with miniaturized photonic structures. This enables measurement speeds exceeding 1000 measurements per second while reducing device volume to a compact form factor suitable for high-repetition-rate laser applications.
Solution Approach 2:
The patent divides the wavelength measurement function into multiple interferometers with different free spectral ranges (FSRs) integrated on a single PIC. By segmenting the measurement range across multiple interferometer channels, the system achieves both high measurement speed and extended wavelength coverage, resolving the contradiction between speed and device complexity.
2Adaptability or versatility
If conventional wavelength meters are used, then ruggedness is adequate for standard applications, but they cannot handle high-repetition-rate lasers with agile output waveforms requiring bandwidths beyond 500 Hz
Solution Approach 1:
The patent implements dynamic tuning capabilities within the PIC by incorporating thermally-tuned interferometers that can rapidly adjust their free spectral ranges. This dynamic adaptability allows the system to track and measure agile laser waveforms with repetition rates exceeding 500 Hz, maintaining measurement accuracy across varying temporal conditions while enhancing versatility for different laser types.
3Measurement precision
If multiple interferometers with different FSRs are integrated on a PIC, then unambiguous wavelength measurement over extended range is achieved, but device complexity increases
Solution Approach 1:
The patent merges multiple interferometers with different free spectral ranges onto a single photonic integrated circuit chip. By combining these interferometers in an integrated architecture with shared waveguides and detectors, the system achieves unambiguous wavelength determination across an extended range while minimizing the increase in device complexity through efficient space utilization and functional integration.
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 PIC-based wavelength meter provides readout capabilities at rates exceeding 1 kHz and bandwidths beyond 500 Hz, enabling precise wavelength determination and servo information in continuous-wave contexts, significantly improving measurement speed and accuracy for high-repetition-rate lasers.
Implementation Method 1
an optical splitter, a plurality of tunable interferometers and one or more detectors. The optical splitter is coupled to the light source, and the interferometers are coupled to the optical splitter. Each interferometer receives a portion of an optical signal of the light source.
Implementation Method 2
measuring optical fringes associated with a number of optical beams by detectors coupled to the interferometers
Data Source
AI summary
An apparatus includes a photonic integrated circuit (PIC) to measure an optical wavelength of a light source. The PIC includes an optical splitter, a plurality of tunable interferometers and one or more detectors. The optical splitter is coupled to the light source, and the interferometers are coupled to the optical splitter. Each interferometer receives a portion of an optical signal of the light source. One or more detectors are coupled to each interferometer, and the interferometers have different free spectral ranges (FSRs). A largest FSR value of the different FSRs is greater than an entire intended wavelength measurement range of the PIC.