Donald R Larson - Academia.edu (original) (raw)
Papers by Donald R Larson
OSA Annual Meeting, 1993
We have developed a simplified approach to the fabrication of a photonic polarization-discriminat... more We have developed a simplified approach to the fabrication of a photonic polarization-discriminating receiver for optical polarimetrie sensor and optical communication applications.
Compact Blue-Green Lasers, 1992
Rare-earth-doped channel waveguide devices have demonstrated to lase in the infrared. The possibi... more Rare-earth-doped channel waveguide devices have demonstrated to lase in the infrared. The possibility for upconversion visible lasing is also being explored.
Optics Letters, Mar 1, 1994
We develop a downstream localized plasma-etching process that permits in situ monitoring of light... more We develop a downstream localized plasma-etching process that permits in situ monitoring of light throughput in a semiconductor-clad channel waveguide as the semiconductor thickness is trimmed. Hydrogenated amorphous silicon films are deposited on ion-exchanged channel waveguides by plasmaenhanced chemical vapor deposition. We then employ the localized plasma-etching process to maximize accurately the extinction ratio between TE and TM polarizations propagating in the clad waveguide. We achieve polarization extinction ratios of greater than 30 dB for both TE-pass and TM-pass polarizers.
Proceedings of SPIE, Feb 8, 1985
ABSTRACT
Proceedings of SPIE, Apr 1, 1996
ABSTRACT
Proceedings of SPIE, Mar 10, 1988
ABSTRACT
Journal of Lightwave Technology, 1995
We have successfully demonstrated an integrated optical TE-TM mode discriminator using waveguide ... more We have successfully demonstrated an integrated optical TE-TM mode discriminator using waveguide polarizers and guided-wave photodetectors for use in polarimetric optical sensor and positioning systems. The photonic integrated circuit consists of a Y-branch waveguide splitter formed by potassiumsodium ion exchange in silicate glass. Hydrogenated amorphous silicon claddings were deposited on each branch of the splitter to act as polarizers. One output cladding was trimmed to a thickness which attenuated the TE polarization, while the other cladding was trimmed to attenuate light having TM polarization. T h e thickness trimming was accomplished using a process of localized plasma etching which allows in situ extinction optimization by monitoring transmitted light. Optical extinction ratios of up to 27 dB were demonstrated on Y-branch waveguides for polarizers with claddings 1.2 mm in length. The integrated receiver was completed with the deposition of metal-semiconductor-metal photodetectors on each of the output waveguide branches following the polarizers. Amorphous silicon claddings were contacted with chrome-gold interdigitated Schottky contacts to form the waveguide detectors.
Proceedings of SPIE, Nov 28, 1983
ABSTRACT
Optics Letters, Feb 15, 1993
Received September 11, 1992 A Y-branch channel waveguide laser whose branch segments were mismatc... more Received September 11, 1992 A Y-branch channel waveguide laser whose branch segments were mismatched in length by 2.4% was fabricated by electric-field-assisted ion exchange in Nd-doped, mixed alkali-silicate glass. The laser output wavelength was centered at ...
Optics Letters, Jul 15, 1991
An optical waveguide is created using the process of ion beam deposition resulting in a waveguide... more An optical waveguide is created using the process of ion beam deposition resulting in a waveguide with low propagation loss, mode discrimination, and gain charac
A measurement system for evaluating the performance of hand-held (HH) and walk-through (WT) metal... more A measurement system for evaluating the performance of hand-held (HH) and walk-through (WT) metal detectors is described. These detectors produce time-varying magnetic fields that interact with objects comprised of electrically conductive and/or magnetizable materials and this interaction allows detection of the object. Detection performance parameters considered are the magnitude of the magnetic field inside the portal region of a WT metal detector and around the HH detector, the ability to detect the presence of small metal objects, the speeds over which small metal objects can be detected, detection repeatability, and discrimination between target objects and innocuous items. Standardized metal objects are used for testing detector sensitivity, and these objects have been defined as threat items by local, state, and federal law enforcement and corrections agencies.
Optical Society of America Annual Meeting, 1990
The efficient transfer of energy from dielectric regions to semiconductor-clad regions in semicon... more The efficient transfer of energy from dielectric regions to semiconductor-clad regions in semiconductor-clad dielectric waveguides is of paramount importance to the operation of waveguide polarizers and detectors. We have experimentally shown that the coupling of energy from dielectric guiding regions to semiconductor-clad regions is highly dependent on cladding thickness and polarization. Accurate tuning of cladding thicknesses allows for the selective attenuation of either TM- or TE-polarized waves, but the opposite polarization (TE or TM, respectively) passes with minimal loss. This effect lends itself well to the fabrication of waveguide polarizers and detectors that respond to only one incident polarization.
Optical Society of America Annual Meeting, 1992
Rare-earth-doped integrated optic waveguide lasers have been demonstrated in glass, LiNbO3, and o... more Rare-earth-doped integrated optic waveguide lasers have been demonstrated in glass, LiNbO3, and other host materials. This technology offers a variety of new components that include diode-pumped amplifiers and lasers. The planar geometry is particularly attractive because selective doping permits the integration of passive and active devices on the same substrate and it is also compatible with pumping by laser diodes. Ion exchanged channel waveguides have been demonstrated to lase near 1060 nm and 1320 nm in Nd-doped silicate and Nd-doped phosphate glass, respectively. Nd-doped waveguide lasers have also been fabricated by chemical vapor deposition; Er-doped waveguide lasers have been similarly fabricated. Y-branch splitters with gain at 1060 nm have been reported in Nd-doped silicate glass waveguides. Ion implantation has been used to form waveguides in Nd-doped YAG and Nd-doped GGG. Nd and Er-doped LiNbO3 waveguide lasers operating near 1060 nm and 1550 nm, respectively, have also been reported. Attempts have been made to demonstrate visible upconversion lasing in Er-doped LiNbO3 and LiTaO3 waveguides. We will review the status of this technology and also highlight some of the more promising applications.
Optics Letters, May 15, 1991
We have fabricated TE- and TM-pass waveguide polarizers with polarization isolations of 42 and 35... more We have fabricated TE- and TM-pass waveguide polarizers with polarization isolations of 42 and 35 dB, respectively. The devices were fabricated by the growth of hydrogenated amorphous silicon claddings on K(+)-Na(+) ionexchanged channel waveguides in glass. Cladding thicknesses were accurately tuned to permit optimum coupling of either a TE or a TM mode to the cladding. We have also demonstrated that a waveguide polarizer attenuation as high as 760 dB/cm can be measured by using a photothermal deflection technique.
Optics Letters, Apr 1, 1990
A continuous-wave integrated-optic channel waveguide laser operating at 1.057 ,m has been fabrica... more A continuous-wave integrated-optic channel waveguide laser operating at 1.057 ,m has been fabricated in neodymium-doped soda-lime-silicate laser glass. The device was end-fire pumped with the 0.528-11m line of an argon-ion laser. Threshold for laser action occurs for an absorbed pump power of 31 mW. The slope efficiency for the integrated-optic laser is estimated to be 0.5%. Field-assisted ion exchange in a eutectic melt of CaNO 3 and KNO 3 was used to form the waveguide.
A method of determining the complex refractive index of a thin film on a nonabsorbing substrate i... more A method of determining the complex refractive index of a thin film on a nonabsorbing substrate is developed. The optical transmittance spectrum of the structure is measured and the index is determined by matching this spectrum numerically. An iterative procedure for finding the magnitude of an induced change in refractive index is also presented. In nonabsorbing spectral regions, the index and film thickness are determined directly. The optical transmittance of sapphire and thin films of gold and epitaxial silicon, both on sapphire, is examined. The refractive index of epitaxial silicon on sapphire, SOS, is determined and compares favorably with the results of other investigators. The measurement method is applied to a thin film of hydrogenated amorphous silicon, a-Si:H, deposited by a capacitively coupled rf glow discharge. The index is tabulated for various wavelengths and a field induced change in index comparable to GaAs is measured.
Journal of Applied Physics, Oct 1, 1990
Coupling interactions between the low loss-modes of dielectric waveguides and the high-loss modes... more Coupling interactions between the low loss-modes of dielectric waveguides and the high-loss modes supported by semiconductor waveguide claddings are of prime importance in the design and fabrication of integrated optical photodetectors and polarizers. It is desirable to maximize energy transfer from dielectric waveguides to semiconductor claddings in order to achieve optimal operation of detectors and polarizers. We have experimentally verified that the intermodal coupling of light from a low-loss dielectric guiding region to a highly absorbing semiconductor cladding region is periodic as a function of cladding thickness. Results were obtained by the in situ monitoring of output intensity during the growth and etching of hydrogenated amorphous silicon on polarization-preserving, D-shaped, optical fiber. Strong correlation exists between theoretical and experimental results for both TE and TM polarizations. The in situ, intensity monitoring technique allows for precise control of attenuation characteristics in clad-waveguide devices allowing for optimum performance of clad-waveguide polarizers and detectors.
Optics Letters, Nov 15, 1992
Waveguide lasers operating near 1092 and 1076 nm were fabricated in Z-cut Nd-Ti codiffused LiTaO ... more Waveguide lasers operating near 1092 and 1076 nm were fabricated in Z-cut Nd-Ti codiffused LiTaO 3. The Nd diffusion was at 1400 0 C for 120 h. Samples from two wafers were examined. The Nd film starting thickness was 7 nm in wafer 1 and 15 nm in wafer 2. Ti stripes, 8-15 Aum wide, were diffused at 1500'C for 4 h for wafer 1 (130-nm stripe thickness) and 2 h for wafer 2 (100-nm stripe thickness). Pumping was at 750 nm. Threshold occurred at 330 mW of absorbed pump power for the best waveguides from wafer 1 and 100 mW for the best waveguides from wafer 2. The slope efficiency of the latter was 0.07%.
Optics Letters, Aug 1, 1991
A Y-branch channel waveguide laser operating near 1057 nm was fabricated by electric-field-assist... more A Y-branch channel waveguide laser operating near 1057 nm was fabricated by electric-field-assisted ion exchange in Nd-doped silicate glass. The overall length was 24 mm. Optical pumping was performed with a cw Ti:sapphire laser. Mirrors were bonded to the polished waveguide facets. The slope efficiency was 5.1% when a 4%-transmitting output coupler was used. Threshold was reached at 26-mW absorbed pump power. The device exhibited a single-pass small-signal gain of 0.034 dB/mW when operated as an amplifier. The 3-dB splitting loss of the Y-branch structure was overcome when the absorbed pump power was approximately 85 mW.
OSA Annual Meeting, 1993
We have developed a simplified approach to the fabrication of a photonic polarization-discriminat... more We have developed a simplified approach to the fabrication of a photonic polarization-discriminating receiver for optical polarimetrie sensor and optical communication applications.
Compact Blue-Green Lasers, 1992
Rare-earth-doped channel waveguide devices have demonstrated to lase in the infrared. The possibi... more Rare-earth-doped channel waveguide devices have demonstrated to lase in the infrared. The possibility for upconversion visible lasing is also being explored.
Optics Letters, Mar 1, 1994
We develop a downstream localized plasma-etching process that permits in situ monitoring of light... more We develop a downstream localized plasma-etching process that permits in situ monitoring of light throughput in a semiconductor-clad channel waveguide as the semiconductor thickness is trimmed. Hydrogenated amorphous silicon films are deposited on ion-exchanged channel waveguides by plasmaenhanced chemical vapor deposition. We then employ the localized plasma-etching process to maximize accurately the extinction ratio between TE and TM polarizations propagating in the clad waveguide. We achieve polarization extinction ratios of greater than 30 dB for both TE-pass and TM-pass polarizers.
Proceedings of SPIE, Feb 8, 1985
ABSTRACT
Proceedings of SPIE, Apr 1, 1996
ABSTRACT
Proceedings of SPIE, Mar 10, 1988
ABSTRACT
Journal of Lightwave Technology, 1995
We have successfully demonstrated an integrated optical TE-TM mode discriminator using waveguide ... more We have successfully demonstrated an integrated optical TE-TM mode discriminator using waveguide polarizers and guided-wave photodetectors for use in polarimetric optical sensor and positioning systems. The photonic integrated circuit consists of a Y-branch waveguide splitter formed by potassiumsodium ion exchange in silicate glass. Hydrogenated amorphous silicon claddings were deposited on each branch of the splitter to act as polarizers. One output cladding was trimmed to a thickness which attenuated the TE polarization, while the other cladding was trimmed to attenuate light having TM polarization. T h e thickness trimming was accomplished using a process of localized plasma etching which allows in situ extinction optimization by monitoring transmitted light. Optical extinction ratios of up to 27 dB were demonstrated on Y-branch waveguides for polarizers with claddings 1.2 mm in length. The integrated receiver was completed with the deposition of metal-semiconductor-metal photodetectors on each of the output waveguide branches following the polarizers. Amorphous silicon claddings were contacted with chrome-gold interdigitated Schottky contacts to form the waveguide detectors.
Proceedings of SPIE, Nov 28, 1983
ABSTRACT
Optics Letters, Feb 15, 1993
Received September 11, 1992 A Y-branch channel waveguide laser whose branch segments were mismatc... more Received September 11, 1992 A Y-branch channel waveguide laser whose branch segments were mismatched in length by 2.4% was fabricated by electric-field-assisted ion exchange in Nd-doped, mixed alkali-silicate glass. The laser output wavelength was centered at ...
Optics Letters, Jul 15, 1991
An optical waveguide is created using the process of ion beam deposition resulting in a waveguide... more An optical waveguide is created using the process of ion beam deposition resulting in a waveguide with low propagation loss, mode discrimination, and gain charac
A measurement system for evaluating the performance of hand-held (HH) and walk-through (WT) metal... more A measurement system for evaluating the performance of hand-held (HH) and walk-through (WT) metal detectors is described. These detectors produce time-varying magnetic fields that interact with objects comprised of electrically conductive and/or magnetizable materials and this interaction allows detection of the object. Detection performance parameters considered are the magnitude of the magnetic field inside the portal region of a WT metal detector and around the HH detector, the ability to detect the presence of small metal objects, the speeds over which small metal objects can be detected, detection repeatability, and discrimination between target objects and innocuous items. Standardized metal objects are used for testing detector sensitivity, and these objects have been defined as threat items by local, state, and federal law enforcement and corrections agencies.
Optical Society of America Annual Meeting, 1990
The efficient transfer of energy from dielectric regions to semiconductor-clad regions in semicon... more The efficient transfer of energy from dielectric regions to semiconductor-clad regions in semiconductor-clad dielectric waveguides is of paramount importance to the operation of waveguide polarizers and detectors. We have experimentally shown that the coupling of energy from dielectric guiding regions to semiconductor-clad regions is highly dependent on cladding thickness and polarization. Accurate tuning of cladding thicknesses allows for the selective attenuation of either TM- or TE-polarized waves, but the opposite polarization (TE or TM, respectively) passes with minimal loss. This effect lends itself well to the fabrication of waveguide polarizers and detectors that respond to only one incident polarization.
Optical Society of America Annual Meeting, 1992
Rare-earth-doped integrated optic waveguide lasers have been demonstrated in glass, LiNbO3, and o... more Rare-earth-doped integrated optic waveguide lasers have been demonstrated in glass, LiNbO3, and other host materials. This technology offers a variety of new components that include diode-pumped amplifiers and lasers. The planar geometry is particularly attractive because selective doping permits the integration of passive and active devices on the same substrate and it is also compatible with pumping by laser diodes. Ion exchanged channel waveguides have been demonstrated to lase near 1060 nm and 1320 nm in Nd-doped silicate and Nd-doped phosphate glass, respectively. Nd-doped waveguide lasers have also been fabricated by chemical vapor deposition; Er-doped waveguide lasers have been similarly fabricated. Y-branch splitters with gain at 1060 nm have been reported in Nd-doped silicate glass waveguides. Ion implantation has been used to form waveguides in Nd-doped YAG and Nd-doped GGG. Nd and Er-doped LiNbO3 waveguide lasers operating near 1060 nm and 1550 nm, respectively, have also been reported. Attempts have been made to demonstrate visible upconversion lasing in Er-doped LiNbO3 and LiTaO3 waveguides. We will review the status of this technology and also highlight some of the more promising applications.
Optics Letters, May 15, 1991
We have fabricated TE- and TM-pass waveguide polarizers with polarization isolations of 42 and 35... more We have fabricated TE- and TM-pass waveguide polarizers with polarization isolations of 42 and 35 dB, respectively. The devices were fabricated by the growth of hydrogenated amorphous silicon claddings on K(+)-Na(+) ionexchanged channel waveguides in glass. Cladding thicknesses were accurately tuned to permit optimum coupling of either a TE or a TM mode to the cladding. We have also demonstrated that a waveguide polarizer attenuation as high as 760 dB/cm can be measured by using a photothermal deflection technique.
Optics Letters, Apr 1, 1990
A continuous-wave integrated-optic channel waveguide laser operating at 1.057 ,m has been fabrica... more A continuous-wave integrated-optic channel waveguide laser operating at 1.057 ,m has been fabricated in neodymium-doped soda-lime-silicate laser glass. The device was end-fire pumped with the 0.528-11m line of an argon-ion laser. Threshold for laser action occurs for an absorbed pump power of 31 mW. The slope efficiency for the integrated-optic laser is estimated to be 0.5%. Field-assisted ion exchange in a eutectic melt of CaNO 3 and KNO 3 was used to form the waveguide.
A method of determining the complex refractive index of a thin film on a nonabsorbing substrate i... more A method of determining the complex refractive index of a thin film on a nonabsorbing substrate is developed. The optical transmittance spectrum of the structure is measured and the index is determined by matching this spectrum numerically. An iterative procedure for finding the magnitude of an induced change in refractive index is also presented. In nonabsorbing spectral regions, the index and film thickness are determined directly. The optical transmittance of sapphire and thin films of gold and epitaxial silicon, both on sapphire, is examined. The refractive index of epitaxial silicon on sapphire, SOS, is determined and compares favorably with the results of other investigators. The measurement method is applied to a thin film of hydrogenated amorphous silicon, a-Si:H, deposited by a capacitively coupled rf glow discharge. The index is tabulated for various wavelengths and a field induced change in index comparable to GaAs is measured.
Journal of Applied Physics, Oct 1, 1990
Coupling interactions between the low loss-modes of dielectric waveguides and the high-loss modes... more Coupling interactions between the low loss-modes of dielectric waveguides and the high-loss modes supported by semiconductor waveguide claddings are of prime importance in the design and fabrication of integrated optical photodetectors and polarizers. It is desirable to maximize energy transfer from dielectric waveguides to semiconductor claddings in order to achieve optimal operation of detectors and polarizers. We have experimentally verified that the intermodal coupling of light from a low-loss dielectric guiding region to a highly absorbing semiconductor cladding region is periodic as a function of cladding thickness. Results were obtained by the in situ monitoring of output intensity during the growth and etching of hydrogenated amorphous silicon on polarization-preserving, D-shaped, optical fiber. Strong correlation exists between theoretical and experimental results for both TE and TM polarizations. The in situ, intensity monitoring technique allows for precise control of attenuation characteristics in clad-waveguide devices allowing for optimum performance of clad-waveguide polarizers and detectors.
Optics Letters, Nov 15, 1992
Waveguide lasers operating near 1092 and 1076 nm were fabricated in Z-cut Nd-Ti codiffused LiTaO ... more Waveguide lasers operating near 1092 and 1076 nm were fabricated in Z-cut Nd-Ti codiffused LiTaO 3. The Nd diffusion was at 1400 0 C for 120 h. Samples from two wafers were examined. The Nd film starting thickness was 7 nm in wafer 1 and 15 nm in wafer 2. Ti stripes, 8-15 Aum wide, were diffused at 1500'C for 4 h for wafer 1 (130-nm stripe thickness) and 2 h for wafer 2 (100-nm stripe thickness). Pumping was at 750 nm. Threshold occurred at 330 mW of absorbed pump power for the best waveguides from wafer 1 and 100 mW for the best waveguides from wafer 2. The slope efficiency of the latter was 0.07%.
Optics Letters, Aug 1, 1991
A Y-branch channel waveguide laser operating near 1057 nm was fabricated by electric-field-assist... more A Y-branch channel waveguide laser operating near 1057 nm was fabricated by electric-field-assisted ion exchange in Nd-doped silicate glass. The overall length was 24 mm. Optical pumping was performed with a cw Ti:sapphire laser. Mirrors were bonded to the polished waveguide facets. The slope efficiency was 5.1% when a 4%-transmitting output coupler was used. Threshold was reached at 26-mW absorbed pump power. The device exhibited a single-pass small-signal gain of 0.034 dB/mW when operated as an amplifier. The 3-dB splitting loss of the Y-branch structure was overcome when the absorbed pump power was approximately 85 mW.