On-Chip Wavelength Locker Eliminates Dead Regions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wavelength lockers, such as single etalon and dual etalon wavelength lockers, and delay line interferometers, face issues with 'dead' regions in their spectra, leading to unreliable or impossible arbitrary wavelength locking due to periodic peaks and valleys, and are also prone to size limitations, vibration sensitivity, dust and condensation issues, and hybrid integration challenges.
Innovation Solution
An integrated optical waveguide device with a waveguide splitter and multiple integrated periodic optical elements, such as multimode interference couplers, generates phase-shifted periodic output signals, eliminating 'dead' regions and allowing for arbitrary wavelength locking without discrete optical elements, thus reducing size, vibration, and dust sensitivity, and avoiding hybrid integration issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single etalon wavelength locker is used, then the device structure is simple, but dead regions appear in the spectrum making arbitrary wavelength locking unreliable
Solution Approach 1:
The invention divides the wavelength locking function into multiple etalons with different FSR values. Instead of relying on a single etalon, the system segments the spectral coverage into multiple overlapping ranges, each handled by a different etalon. This segmentation eliminates dead regions while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The invention changes the FSR parameter of the etalon by using multiple etalons with different FSR values (e.g., 50 GHz and 100 GHz). This parameter variation allows the system to cover different spectral ranges and eliminate dead regions, improving wavelength locking reliability across the entire C-band while maintaining reasonable device complexity.
2Reliability
If a dual etalon wavelength locker is used to eliminate dead regions, then wavelength locking reliability improves, but device complexity and size increase
Solution Approach 1:
The invention assigns different local qualities (FSR values) to different etalons based on their specific functions. The first etalon (50 GHz FSR) handles fine wavelength resolution, while the second etalon (100 GHz FSR) handles broader spectral coverage. This local quality differentiation eliminates dead regions without requiring a uniformly complex device structure.
Solution Approach 2:
The wavelength locking function is segmented into multiple etalons with specialized roles. The first etalon covers specific spectral regions with high resolution, while the second etalon covers broader regions. This functional segmentation improves reliability by eliminating dead regions while controlling overall device complexity through division of labor.
3Ease of manufacture
If discrete optical elements are used in conventional DLI, then the device can be built with standard components, but the device size increases and vibration sensitivity increases
Solution Approach 1:
The invention merges multiple discrete optical elements (etalons, beam splitters, mirrors, detectors) into a single integrated photonic circuit. This consolidation dramatically reduces device size from a large benchtop setup to a compact chip-scale device while maintaining the wavelength locking function. The integration also eliminates vibration sensitivity associated with discrete mechanical components.
Solution Approach 2:
The invention replaces the mechanical system of discrete optical elements with an integrated photonic circuit implementation. Instead of using physical beam splitters, mirrors, and etalons that are sensitive to vibration and occupy large space, the system uses waveguide-based optical elements fabricated on a chip, eliminating mechanical sensitivity and reducing size.
4Ease of manufacture
If conventional DLI with discrete elements is used, then the device can be assembled with standard components, but vibration sensitivity and dust sensitivity increase
Solution Approach 1:
The invention merges all optical path elements into a single integrated photonic circuit, eliminating the open optical paths that are susceptible to dust and vibration. The entire optical system is enclosed within the chip structure, protecting it from environmental harmful factors while maintaining ease of manufacture through standard photonic fabrication processes.
Solution Approach 2:
The invention substitutes the mechanical assembly of discrete optical elements with an integrated photonic circuit implementation. This replacement eliminates the vibration and dust sensitivity inherent in mechanical optical systems, as the waveguide-based implementation is inherently protected from environmental factors while remaining manufacturable using standard semiconductor fabrication techniques.
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 integrated optical waveguide device enables reliable arbitrary wavelength locking across a wide band without 'dead' regions, is compact, less sensitive to environmental factors, and reduces optical feedback, improving the reliability and operational stability of the locking process.
Implementation Method 1
Optical power in each output optical signal depends on a difference in optical path length between arms of the conventional DLI and on a wavelength of the light
Implementation Method 2
each integrated periodic optical element to: receive a respective portion of the input optical signal after splitting of the input optical signal by the optical waveguide splitter, and provide, based on the respective portion of the input optical signal, a respective periodic output optical signal
Implementation Method 3
a plurality of integrated photodiodes to receive the plurality of periodic output optical signals in association with wavelength locking the laser
Data Source
AI summary
An on-chip wavelength locker may include an optical waveguide splitter to split an input optical signal received from a laser. The on-chip wavelength locker may include a plurality of integrated periodic optical elements, each to receive a respective portion of the input optical signal after splitting of the input optical signal by the optical waveguide splitter, and provide, based on the respective portion of the input optical signal, a respective periodic output optical signal of a plurality of periodic output optical signals. Each periodic output optical signal, of the plurality of periodic output optical signals, may be phase shifted with respect to other periodic output optical signals of the plurality of periodic output optical signals. The on-chip wavelength locker may include a plurality of integrated photodiodes to receive the plurality of periodic output optical signals in association with wavelength locking the laser.