$LWLG Protection layers for polymer modulators/waveguides
United States Patent 10,520,673
Becker , et al. December 31, 2019
FIELD OF THE INVENTION
This invention relates to protection layers for use in polymer waveguides and especially in polymer modulators.
BACKGROUND OF THE INVENTION
Laser modulators have been in use for 20 years. Initially discrete lasers were positioned next to discrete modulators so that higher performance signaling (and speeds above 10 Gbps) could be attained. While this technique has been commercialized it is not optimized. That is it does not reach the low cost targets, or space/size requirements, and takes lots of time to align the components, place them, package them, and test them.
In two copending patent applications semiconductor lasers and polymer modulators are integrated on a common platform to provide more efficient coupling between the source laser and the optical modulator. A first one of the two applications is entitled "Polymer Modulator and Laser Integrated on a common Platform and Method", filed Aug. 31, 2017, with Ser. No. 15/692,080, and a second one of the two applications is entitled "Guide Transition Device with Digital Grating Deflectors and Method" filed Nov. 14, 2017, with Ser. No. 15/812,630, both are incorporated herein by reference.
In the preferred process for fabricating the polymer modulators/waveguides the various layers are deposited in liquid form, which involves the use of solvents. These solvents can affect the abutting or surrounding layers. Also, the polymer modulators generally operate through the application of an electrical field, which is generally produced by connecting electrical contacts on opposed sides of the modulator. Thus, care must be taken to eliminate or minimize electrical leakage through the various polymer layers. Further, because the polymer modulators/waveguides are basically a "sandwich" of layers, which may or may not vary in characteristics, the index of refraction for the various layers must be considered.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object of the present invention to provide new and improved protection layers for use in polymer modulators/waveguides.
It is another object of the present invention to provide new and improved protection layers that provide protection from various solvents, gasses and for electrical charges.
It is another object of the present invention to provide new and improved protection layers that provide optical continuity with similar optical refractive indices for cladding and core layers.
SUMMARY OF THE INVENTION
Briefly to achieve the desired objects and advantages of the instant invention in accordance with a preferred embodiment a polymer waveguide/modulator includes a lower cladding layer, a polymer core, an upper cladding layer, a first protection/barrier layer sandwiched between the lower cladding layer and the core, and a second protection/barrier layer sandwiched between the core and the upper cladding layer. The protection/barrier layers are designed to protect the lower and upper cladding layers and the core from solvents and gases and to prevent current leakage between the cladding layers and the core. The first protection/barrier layer is optically transparent and designed with a refractive index less than, greater than, or the same as the refractive index of the core and approximately equal to the refractive index of the lower cladding layer. The second protection/barrier layer is optically transparent and designed with a refractive index less than, greater than, or the same as the refractive index of the core and approximately equal to the refractive index of the upper cladding layer. Generally, it should be understood that both the first and second protection/barrier layers are thin enough that differences between indexes of refraction of a protection/barrier layer and a core or cladding layer does not significantly affect light guiding of the waveguide/modulator.
To further achieve the desired objects and advantages of the present invention a specific embodiment of a polymer waveguide/modulator including a lower cladding layer having a refractive index, the lower cladding layer including one of polymer material, dielectric material or semiconductor based material, a polymer core having a refractive index, a polymer upper cladding layer having a refractive index, a first protection/barrier layer sandwiched between the lower cladding layer and the core, and a second protection/barrier layer sandwiched between the core and the upper cladding layer. The first protection/barrier layer is designed to protect the lower cladding layer and the core from solvents and gases and to prevent current leakage between the lower cladding layer and the core. The first protection/barrier layer is optically transparent to light wavelengths in a range of 0.8 .mu.m to 2 .mu.m and is designed with a refractive index less than, greater than, or the same as the refractive index of the core and approximately equal to the refractive index of the lower cladding layer. The first protection/barrier layer includes one of metal material, dielectric material or semiconductor based material. The second protection/barrier layer is designed to protect the upper cladding layer and the core from solvents and gases and to prevent current leakage between the upper cladding layer and the core. The second protection/barrier layer is optically transparent to light wavelengths in a range of 0.8 .mu.m to 2 .mu.m and designed with a refractive index less than, greater than, or the same as the refractive index of the core and approximately equal to the refractive index of the upper cladding layer. The second protection/barrier layer includes one of metal material, dielectric material or semiconductor based material.
To further achieve the desired objects and advantages of the present invention, provided is a method of fabricating a polymer waveguide/modulator comprising the steps of: providing a platform; depositing a lower cladding layer having a refractive index on the platform; depositing a first protection/barrier layer on the lower cladding layer using a deposition technique including one of PVD, CVD, evaporation, sputtering, or MOCVD/MBE, the first protection/barrier layer including one of metal material, dielectric material or semiconductor based material; depositing a polymer core on the first protection/barrier layer, the polymer core having a refractive index, the first protection/barrier layer being designed to protect the lower cladding layer and the core from solvents and gases and to prevent current leakage between the lower cladding layer and the core, and the first protection/barrier layer being optically transparent to light wavelengths in a range of 0.8 .mu.m to 2 .mu.m and designed with a refractive index less than, greater than, or the same as the refractive index of the core; depositing a second protection/barrier layer on the polymer core using a deposition technique including one of PVD, CVD, evaporation, sputtering, or MOCVD/MBE, and the second protection/barrier layer being optically transparent to light wavelengths in a range of 0.8 .mu.m to 2 .mu.m and designed with a refractive index less than, greater than, or the same as the refractive index of the core, the second protection/barrier layer including one of metal material, dielectric material or semiconductor based material; and depositing an upper cladding layer having a refractive index on the second protection/barrier layer, the second protection/barrier layer being designed to protect the upper cladding layer and the core from solvents and gases and to prevent current leakage between the upper cladding layer and the core, and the refractive index of the upper cladding layer being approximately equal to the refractive index of the second protection/barrier layer.
http://patft.uspto.gov/netacgi/nph-Parser?Sec...e+logic%22
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United States Patent 10,520,673
Becker , et al. December 31, 2019
FIELD OF THE INVENTION
This invention relates to protection layers for use in polymer waveguides and especially in polymer modulators.
BACKGROUND OF THE INVENTION
Laser modulators have been in use for 20 years. Initially discrete lasers were positioned next to discrete modulators so that higher performance signaling (and speeds above 10 Gbps) could be attained. While this technique has been commercialized it is not optimized. That is it does not reach the low cost targets, or space/size requirements, and takes lots of time to align the components, place them, package them, and test them.
In two copending patent applications semiconductor lasers and polymer modulators are integrated on a common platform to provide more efficient coupling between the source laser and the optical modulator. A first one of the two applications is entitled "Polymer Modulator and Laser Integrated on a common Platform and Method", filed Aug. 31, 2017, with Ser. No. 15/692,080, and a second one of the two applications is entitled "Guide Transition Device with Digital Grating Deflectors and Method" filed Nov. 14, 2017, with Ser. No. 15/812,630, both are incorporated herein by reference.
In the preferred process for fabricating the polymer modulators/waveguides the various layers are deposited in liquid form, which involves the use of solvents. These solvents can affect the abutting or surrounding layers. Also, the polymer modulators generally operate through the application of an electrical field, which is generally produced by connecting electrical contacts on opposed sides of the modulator. Thus, care must be taken to eliminate or minimize electrical leakage through the various polymer layers. Further, because the polymer modulators/waveguides are basically a "sandwich" of layers, which may or may not vary in characteristics, the index of refraction for the various layers must be considered.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object of the present invention to provide new and improved protection layers for use in polymer modulators/waveguides.
It is another object of the present invention to provide new and improved protection layers that provide protection from various solvents, gasses and for electrical charges.
It is another object of the present invention to provide new and improved protection layers that provide optical continuity with similar optical refractive indices for cladding and core layers.
SUMMARY OF THE INVENTION
Briefly to achieve the desired objects and advantages of the instant invention in accordance with a preferred embodiment a polymer waveguide/modulator includes a lower cladding layer, a polymer core, an upper cladding layer, a first protection/barrier layer sandwiched between the lower cladding layer and the core, and a second protection/barrier layer sandwiched between the core and the upper cladding layer. The protection/barrier layers are designed to protect the lower and upper cladding layers and the core from solvents and gases and to prevent current leakage between the cladding layers and the core. The first protection/barrier layer is optically transparent and designed with a refractive index less than, greater than, or the same as the refractive index of the core and approximately equal to the refractive index of the lower cladding layer. The second protection/barrier layer is optically transparent and designed with a refractive index less than, greater than, or the same as the refractive index of the core and approximately equal to the refractive index of the upper cladding layer. Generally, it should be understood that both the first and second protection/barrier layers are thin enough that differences between indexes of refraction of a protection/barrier layer and a core or cladding layer does not significantly affect light guiding of the waveguide/modulator.
To further achieve the desired objects and advantages of the present invention a specific embodiment of a polymer waveguide/modulator including a lower cladding layer having a refractive index, the lower cladding layer including one of polymer material, dielectric material or semiconductor based material, a polymer core having a refractive index, a polymer upper cladding layer having a refractive index, a first protection/barrier layer sandwiched between the lower cladding layer and the core, and a second protection/barrier layer sandwiched between the core and the upper cladding layer. The first protection/barrier layer is designed to protect the lower cladding layer and the core from solvents and gases and to prevent current leakage between the lower cladding layer and the core. The first protection/barrier layer is optically transparent to light wavelengths in a range of 0.8 .mu.m to 2 .mu.m and is designed with a refractive index less than, greater than, or the same as the refractive index of the core and approximately equal to the refractive index of the lower cladding layer. The first protection/barrier layer includes one of metal material, dielectric material or semiconductor based material. The second protection/barrier layer is designed to protect the upper cladding layer and the core from solvents and gases and to prevent current leakage between the upper cladding layer and the core. The second protection/barrier layer is optically transparent to light wavelengths in a range of 0.8 .mu.m to 2 .mu.m and designed with a refractive index less than, greater than, or the same as the refractive index of the core and approximately equal to the refractive index of the upper cladding layer. The second protection/barrier layer includes one of metal material, dielectric material or semiconductor based material.
To further achieve the desired objects and advantages of the present invention, provided is a method of fabricating a polymer waveguide/modulator comprising the steps of: providing a platform; depositing a lower cladding layer having a refractive index on the platform; depositing a first protection/barrier layer on the lower cladding layer using a deposition technique including one of PVD, CVD, evaporation, sputtering, or MOCVD/MBE, the first protection/barrier layer including one of metal material, dielectric material or semiconductor based material; depositing a polymer core on the first protection/barrier layer, the polymer core having a refractive index, the first protection/barrier layer being designed to protect the lower cladding layer and the core from solvents and gases and to prevent current leakage between the lower cladding layer and the core, and the first protection/barrier layer being optically transparent to light wavelengths in a range of 0.8 .mu.m to 2 .mu.m and designed with a refractive index less than, greater than, or the same as the refractive index of the core; depositing a second protection/barrier layer on the polymer core using a deposition technique including one of PVD, CVD, evaporation, sputtering, or MOCVD/MBE, and the second protection/barrier layer being optically transparent to light wavelengths in a range of 0.8 .mu.m to 2 .mu.m and designed with a refractive index less than, greater than, or the same as the refractive index of the core, the second protection/barrier layer including one of metal material, dielectric material or semiconductor based material; and depositing an upper cladding layer having a refractive index on the second protection/barrier layer, the second protection/barrier layer being designed to protect the upper cladding layer and the core from solvents and gases and to prevent current leakage between the upper cladding layer and the core, and the refractive index of the upper cladding layer being approximately equal to the refractive index of the second protection/barrier layer.
http://patft.uspto.gov/netacgi/nph-Parser?Sec...e+logic%22
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