Showing papers by "Daniel D. Stancil published in 1996"
TL;DR: The first integrated quasi-phase-matched second-harmonic generator and electrooptic scanner on ferroelectric Z-cut LiTaO/sub 3 was reported in this article.
Abstract: We report the first integrated quasi-phase-matched second-harmonic generator and electrooptic scanner on ferroelectric Z-cut LiTaO/sub 3/. The quasi-phase-matched second-harmonic generation device frequency doubles the infrared light at 829.7 nm into blue at 414.85 nm with a bulk conversion efficiency of 0.52%/W-cm. The blue light generated in the bulk then passes through an electrooptic scanner, consisting of a series of lithographically defined triangular-shaped domain-inverted regions extending through the thickness of the crystal. A deflection of 12 mrad/kv for the output blue light and 7.4 mrad/kv for the infrared light was observed at the scanner output.
31 citations
TL;DR: In this article, the authors have demonstrated both wafer and waveguide electrooptic beam scanners in KTiOPO4 using alternating domain-inverted triangular patterns in the substrate.
Abstract: We have fabricated and demonstrated both wafer and waveguide electro‐optic beam scanners in KTiOPO4 using alternating domain‐inverted triangular patterns in the substrate. This device is an extension of previous work in LiTaO3. The domain inversion was achieved by pulsed electric field poling. The deflection sensitivity was 2.1 mrad/kV, compared to the calculated value of 2.3 mrad/kV for this geometry. The bandwidth of the devices was measured to be at least 200 kHz, which was limited by the high voltage driver.
23 citations
TL;DR: In this paper, the profile of magnetostatic forward volume waves along the direction of propagation is measured using the transverse interaction with optical guided modes using a microwave input power of up to 700 mW in the frequency range of 6-8 GHz.
Abstract: The profile of magnetostatic forward volume waves along the direction of propagation is measured using the transverse interaction with optical guided modes. The technique is used in regimes of both linear and nonlinear magnetostatic wave excitation. A microwave input power of up to 700 mW in the frequency range of 6-8 GHz was used to excite magnetostatic waves in a 6.3 /spl mu/m film of (BiLu)/sub 3/Fe/sub 5/O/sub 12/. The optical wavelength used in the experiment was 1.32 /spl mu/m. At distances beyond about 1 min from the transducer, we observed an approximately exponential decay with a rate of about 40 dB/cm. The profile departs from an exponential shape at distances closer than 1 mm, owing, we believe, to transducer fringing field effects and the finite resolution of the probe beam. The nonlinear microwave frequency shift of the interaction spectrum was also observed at high magnetostatic wave power levels.
17 citations
10 May 1996
TL;DR: In this article, a novel electro-optic beam deflector is reported based on ferroelectric domain inversion extending through the thickness of a Z-cut LiTaO 3 wafer.
Abstract: A novel electro-optic beam deflector is reported based on ferroelectric domain inversion extending through the thickness of a Z-cut LiTaO 3 wafer. The selective domain inversion is achieved by electric-field poling assisted by proton exchange, rather than proton exchange followed by rapid thermal annealing. The deflection sensitivity of the device was measured to be 5.0 mrad/KV. This is 93% of the theoretical value for this geometry, and a significant improvement over the value of 80% of theoretical previously reported for a waveguide deflector.
15 citations
TL;DR: In this article, a novel electrooptic beam deflector is reported based on ferroelectric domain inversion extending through the thickness of a Z-cut LiTaO/sub 3/ wafer.
Abstract: A novel electrooptic beam deflector is reported based on ferroelectric domain inversion extending through the thickness of a Z-cut LiTaO/sub 3/ wafer. The selective domain inversion is achieved by electric-field poling assisted by proton exchange, rather than proton exchange followed by rapid thermal annealing. The deflection sensitivity of the device was measured to be 5.0 mrad/KV. This is 93% of the theoretical value for this geometry, and a significant improvement over the value of 80% of theoretical previously reported for a waveguide deflector. This improvement is attributed to the new domain inversion process. No degradation of deflection sensitivity is observed up to the frequency of 300 KHz, which is then limited by the response time of detectors.
15 citations
01 May 1996
TL;DR: In this paper, a nonlinear shift in the wavelength of the magnetostatic waves at high power along with magnetic damping is proposed to explain the optical spectrum changes observed at high microwave power levels.
Abstract: In the collinear interaction between magnetostatic waves and optical guided modes, the use of high microwave power is experimentally observed to broaden the range of microwave frequencies over which a significant optical mode conversion occurs. A mechanism contributing to this broadening is described that is based on a nonlinear shift in the wavelength of the magnetostatic waves at high power along with magnetic damping. Comparisons between previous experiments and our theoretical predictions show that this mechanism can explain some, but not all, of the changes observed in the optical spectrum at high microwave power levels.
15 citations
TL;DR: The Kronig-Penney model correctly gives the effective refractive index of the layer, gives insight into the electric field profiles at different points on the dispersion curve, and leads to a qualitative explanation of why the optical loss diminishes at both large and small duty cycles.
Abstract: Physical insight into the propagation characteristics of periodically segmented waveguides can be obtained by viewing the guiding layer as a thin slab of an idealized infinite medium with periodic layers along the direction of propagation. One can analyze the properties of this infinite medium using a formal analogy with the Kronig-Penney model used to describe the propagation of electron wave functions in a periodic crystal potential. The model correctly gives the effective refractive index of the layer, gives insight into the electric field profiles at different points on the dispersion curve, and leads to a qualitative explanation of why the optical loss diminishes at both large and small duty cycles.
14 citations
TL;DR: In this paper, non-monotonic variations in the magneto-optic coupling coefficient are observed as we increase the input microwave power at a fixed frequency, though the features appear at higher power levels.
Abstract: Magnetostatic wave-optical interactions are studied in the transverse geometry using a [BiLu]/sub 3/Fe/sub 5/O/sub 12/ film. Non-monotonic variations in the magneto-optic coupling coefficient are observed as we increase the input microwave power at a fixed frequency. Similar variations are also seen in the transmitted microwave signal, though the features appear at higher power levels. The non-monotonic behavior is due to a shift in the microwave passband with increasing power. Density plots are used to correlate the two sets of data over a 350 MHz region. The discrepancy in power levels associated with a feature in the line plots is a consequence of the different curvatures of the two density plots.
8 citations
TL;DR: In this paper, high power microwave experiments conducted on a rectangular yttrium-iron-garnet (YIG) film indicate a parabolic dependence of the square of the frequency of auto-oscillations on microwave signal amplitudes.
Abstract: High power microwave experiments conducted on a rectangular yttrium‐iron‐garnet (YIG) film indicate a parabolic dependence of the square of the frequency of auto‐oscillations on microwave signal amplitudes, an observation that is qualitatively consistent with prior theoretical predictions. Forward volume magnetostatic waves were excited using a microstrip transducer kept in contact with a YIG film placed in a constant external magnetic field (Hdc=3.48 kG). Variations in the input microwave power (10 dBm
8 citations
Patent•
14 May 1996TL;DR: In this article, an integrated frequency conversion and scanner for converting the frequency of an input light beam and deflecting the converted light beam through an electronically controlled angle is disclosed, which includes an electrooptic crystal including a region formed for converting frequency of the input light to a higher frequency; and a field changing structure associated with selected regions of the crystal arranged so that an electric field is created at least partially within the crystal to change its refractive index to thereby deflect the conduction signal through an electronic controlled angle.
Abstract: An integrated frequency conversion and scanner for converting the frequency of an input light beam and deflecting the converted light beam through an electronically controlled angle is disclosed. This structure includes an electrooptic crystal including a region formed for converting the frequency of the input light to a higher frequency; and a field changing structure associated with selected regions of the crystal arranged so that an electric field is created at least partially within the crystal to change its refractive index to thereby deflect the converted light beam through an electronically controlled angle.
7 citations
01 Jan 1996
TL;DR: In this paper, a novel electrooptic beam deflector is reported based on ferroelectric domain inversion extending through the thickness of a Z-cut LiTaOa wafer.
Abstract: Abstruct-A novel electrooptic beam deflector is reported based on ferroelectric domain inversion extending through the thickness of a Z-cut LiTaOa wafer. The selective domain inversion is achieved by electric-field poling assisted by proton exchange, rather than proton exchange followed by rapid thermal annealing. The deflection sensitivity of the device was measured to be 5.0 mrad/KV. This is 93% of the theoretical value for this geometry, and a significant improvement over the value of 80 % of theoretical previously reported for a waveguide deflector. This improvement is attributed to the new domain inversion process. No degradation of deflection sensitivity is observed up to the frequency of 300 KHz, which is then limited by the response time of detectors.
TL;DR: In this article, an anomalously large electro-optic modulation effect was observed in KTiOPO4 waveguides fabricated under various conditions, and a space charge model relating the mobile charge, space charge field, and observed enhancement in the electro optic modulation was proposed to explain the mechanism of this effect.
Abstract: We report the observation of an anomalously large electro‐optic modulation effect in potassium titanyl phosphate (KTiOPO4) waveguides fabricated under various conditions. An interferometric method was used to measure the effective electro‐optic coefficient in the waveguides by measuring the phase retardation of an optical mode when a voltage was applied across the substrate. We observed that at low modulation frequency the effective electro‐optic coefficient in the waveguides can be higher than the bulk value by a factor up to about 100. A space charge model relating the mobile charge, space charge field, and observed enhancement in the electro‐optic modulation is proposed to explain the mechanism of this effect. Calculation for dc steady state, small signal analysis, and large signal simulation is compared to the experimental observation. Possible device application and long term effects on system operation are also discussed.
10 May 1996
TL;DR: In this paper, the authors report on the deposition of c-axis oriented LiNbO3 planar waveguides on silicon substrates and employ a combined SiO2/Si3N4 cladding layer to provide both optical confinement and barrier layer to prevent Li diffusion into the SiO 2.
Abstract: We report on the deposition of c-axis oriented LiNbO3 planar waveguides on silicon substrates. We have employed a combined SiO2/Si3N4 cladding layer to provide both optical confinement in the LiNbO3 as well as acting as a barrier layer to prevent Li diffusion into the SiO2. LiNbO3 films displaying exclusively the (006) reflection (no other orientations) in x-ray diffraction spectra have been produced. Post deposition rapid thermal annealing has been employed to improve the crystallinity of these films. Optical losses of about 18 dB/cm were measured for these films. We discuss the deposition conditions, the role of the silicon nitride in determining the LiNbO3 texture, as well as the performance of these layers as planar optical waveguides.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
01 Jan 1996
TL;DR: The first integrated quasi-phase-matched second-harmonic generator and electrooptic scanner on ferroelec- tric Z-cut LiTaOs was reported in this article.
Abstract: We report the first integrated quasi-phase-matched second-harmonic generator and electrooptic scanner on ferroelec- tric Z-cut LiTaOs. The quasi-phase-matched second-harmonic generation device frequency doubles the infrared light at 829.7 nm into blue at 414.85 nm with a bulk coversion efficiency of 0.52%/W-cm. The blue light generated in the bulk then passes through an electrooptic scanner, consisting of a series of litho- graphically defined triangular-shaped domain-inverted regions extending through the thickness of the crystal. A deflection of 12 mradfkv for the output blue light and 7.4 Yradlkv for the infrared light was observed at the scanner output.
10 May 1996
TL;DR: In this paper, an interferometric method was used to measure the effective electro-optic coefficient r33 in the waveguides by measuring the phase retardation of an optical mode when a voltage is applied across the substrate.
Abstract: We report the observation of an anomalously large electro-optic coefficient in potassium titanyl phosphate (KTiOPO4, KTP) waveguides fabricated under various conditions. An interferometric method was used to measure the effective electro-optic coefficient r33 in the waveguides by measuring the phase retardation of an optical mode when a voltage is applied across the substrate. We observe that at low frequency the waveguide electro-optic coefficient can be higher than the bulk value by a factor up to about 100. Since KTP crystals are known to have a high concentration of mobile ions, a model relating the mobile charges, space charge fields, and observed enhancement in r33 is proposed to explain the mechanism of this effect. Possible device application and long term effects on system operation are also discussed.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.