Ultra-Small Tunable Laser Assembly With Integrated Thermal SBS Suppression
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Solution Overview
Problem
Current tunable lasers for optical networks face challenges in achieving an ultra-small form factor while maintaining high performance, particularly in applications requiring compactness and reliability for dense-wavelength division-multiplexing (DWDM) networks.
Innovation Solution
An external cavity tunable laser is designed with a hermetically sealed housing of less than 0.15 cubic centimeters, incorporating a gain medium, collimate lens, etalons for frequency tuning, an actuator for optical pathlength adjustment, bandpass filter, beam splitter, reflection mirror, and isolator, along with integrated etalons and phase tuner with heaters to suppress stimulated Brillouin scattering and ensure thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the laser assembly is reduced to an ultra-small form factor, then compactness is improved, but thermal management and suppression of stimulated Brillouin scattering become more difficult
Solution Approach 1:
The patent combines multiple functions into integrated components: the etalons are integrated with the gain medium waveguide, and the phase tuner heater is integrated directly onto the gain medium chip. This merging allows for compact thermal management despite the small package size, as the heating elements are positioned in direct thermal contact with the components that require temperature control.
Solution Approach 2:
The patent introduces thermal isolation structures as intermediaries between different components. Specifically, thermal isolation layers or structures are placed between the etalons and the gain medium to prevent unwanted thermal coupling, allowing each component to be thermally managed independently within the constrained volume.
2Volume of moving object
If the package size is reduced to less than 0.15 cubic centimeters, then compactness is improved, but thermal isolation for each component becomes difficult
Solution Approach 1:
Multiple optical components are merged into a single integrated assembly where the etalons are directly coupled to the gain medium waveguide, and the phase tuner is integrated onto the same chip. This integration reduces the number of separate thermal management systems needed, simplifying the overall thermal isolation requirements despite the ultra-compact size.
3Reliability
If integrated etalons and phase tuner with heaters are used, then stimulated Brillouin scattering is suppressed and wavelength locking is improved, but device complexity increases
Solution Approach 1:
The etalons are integrated directly with the gain medium waveguide, and the phase tuner heater is deposited directly onto the gain medium chip. This merging of components reduces the number of separate assemblies needed and simplifies the overall device structure, even though the functional capabilities are enhanced.
Solution Approach 2:
The integrated heater structure provides self-regulated temperature control for the gain medium, enabling automatic suppression of stimulated Brillouin scattering and wavelength locking without requiring external control systems. The heater responds directly to the thermal conditions of the gain medium itself.
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 solution enables a compact, high-performance tunable laser assembly that reduces deployment barriers for high-capacity DWDM networks, integrates laser source and modulator into a single reliable package, and effectively suppresses thermal issues and Brillouin scattering.
Implementation Method 1
a gain medium module to generate a broadband optical spectrum covering a predetermined wavelength range
Implementation Method 2
a collimate lens turning a diverging beam into a collimated beam
Implementation Method 3
a pair of etalons to tune frequency
Implementation Method 4
a bandpass filter to block one or more frequencies outside the predetermined wavelength range
Implementation Method 5
a beam splitter to split a percentage of the beam to a photodetector
Implementation Method 6
an isolator for preventing reflecting light back to the external cavity
Implementation Method 7
A heater can be directly deposited on top of the gain median waveguide for suppression of stimulated Brillouin scattering
Data Source
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AI summary
An external cavity tunable laser includes a gain median module to generate a broadband optical spectrum covering a predetermined wavelength range; a collimate lens turning a diverging beam into a collimated beam; a pair of etalons to tune frequency; an actuator to adjust an external cavity optical pathlength; a bandpass filter to block one or more frequencies outside the predetermined wavelength range; a beam splitter to split a percentage of the beam to a photodetector; a reflection mirror for feedback to gain median waveguide; an isolator for preventing reflecting light back to the external cavity; and a hermetically sealed housing less than 0.15 cubic centimeters.