Athermal Laser Using NTOC Waveguide for Wavelength Stability
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Solution Overview
Problem
Existing athermal lasers face challenges in achieving wavelength stability without heating elements or thermoelectric coolers, particularly with hybrid lasers using III-V gain material, which experiences significant thermal drift, and external cavity lasers are not commercially viable due to size and efficiency issues.
Innovation Solution
A thermally compensating athermal laser design incorporating a reflective gain medium coupled to a spot-size converter and a negative thermo-optic coefficient waveguide, where the optical signal passes through a silicon waveguide and an NTOC waveguide, effectively stabilizing the wavelength by matching the effective thermo-optic coefficients of the lasing cavity segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If heating elements or thermoelectric coolers are used to control wavelength, then wavelength stability is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent removes heating elements and thermoelectric coolers from the laser system, extracting the temperature control components entirely. Instead, it uses an athermal design where the laser cavity structure itself compensates for thermal effects through the interplay of materials with different thermo-optic coefficients, eliminating the need for active temperature control hardware.
Solution Approach 2:
The laser system achieves self-compensation for thermal drift through its inherent structure. The NTOC waveguide and gain medium combination automatically compensates for thermal expansion and refractive index changes without external control, allowing the system to self-regulate its wavelength stability passively.
2Stability of the object's composition
If heating elements or thermoelectric coolers are used to control wavelength, then wavelength stability is improved, but energy consumption increases
Solution Approach 1:
The patent removes heating elements and thermoelectric coolers from the laser system, extracting the temperature control components entirely. Instead, it uses an athermal design where the laser cavity structure itself compensates for thermal effects through the interplay of materials with different thermo-optic coefficients, eliminating the need for active temperature control hardware.
Solution Approach 2:
The laser system achieves self-compensation for thermal drift through its inherent structure. The NTOC waveguide and gain medium combination automatically compensates for thermal expansion and refractive index changes without external control, allowing the system to self-regulate its wavelength stability passively.
3Stability of the object's composition
If external cavity lasers are used to reduce thermal drift, then wavelength stability is improved, but device size increases and efficiency decreases
Solution Approach 1:
The patent changes the material parameters of the waveguide, specifically using materials with negative thermo-optic coefficients. This parameter change allows the waveguide to compensate for thermal drift through its inherent optical properties rather than through geometric expansion of the cavity, maintaining a compact form factor while achieving wavelength stability.
Solution Approach 2:
The laser system uses composite material structures combining NTOC materials with the gain medium. This composite approach enables thermal compensation at the material level within the compact laser cavity, avoiding the need for large external cavity structures while maintaining wavelength 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
The design achieves stable wavelength operation across temperature variations without heating elements or thermoelectric coolers, reducing energy requirements and wavelength spacing, while maintaining efficiency and scalability.
Implementation Method 1
a negative thermo-optic coefficient (NTOC) waveguide comprised of an NTOC material is fabricated on top of the SSC. In this way, an optical signal, which originates from the RGM, passes into the SSC, is coupled into the NTOC waveguide, passes through the NTOC waveguide, and is coupled back into the SSC
Implementation Method 2
The SSC converts an optical mode-field size of the RGM to an optical mode-field size of the silicon waveguide
Data Source
AI summary
A laser includes a reflective gain medium (RGM) comprising an optical gain material coupled with an associated reflector. The RGM is coupled to a spot-size converter (SSC), which optically couples the RGM to an optical reflector through a silicon waveguide. The SSC converts an optical mode-field size of the RGM to an optical mode-field size of the silicon waveguide. A negative thermo-optic coefficient (NTOC) waveguide is fabricated on top of the SSC. In this way, an optical signal, which originates from the RGM, passes into the SSC, is coupled into the NTOC waveguide, passes through the NTOC waveguide, and is coupled back into the SSC before passing into the silicon waveguide. During operation, the RGM, the spot-size converter, the NTOC waveguide, the silicon waveguide and the silicon mirror collectively form a lasing cavity for the athermal laser. Finally, a laser output is optically coupled to the lasing cavity.