A new Rayleigh quotient, which was introduced and briefly considered in a previous paper, is now examined in greater detail. When used in conjunction with polarised finite difference schemes established in earlier pap...
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A new Rayleigh quotient, which was introduced and briefly considered in a previous paper, is now examined in greater detail. When used in conjunction with polarised finite difference schemes established in earlier papers, it enables semivectorial E-field and H-field propagation modes of waveguide structures, which may contain any arbitrary distribution of horizontal and vertical dielectric discontinuities, to be determined without the need to solve matrix eigenvalue problems. The absence of a matrix enables the finite difference grid to incorporate substantially more points and smaller step lengths, thereby improving the accuracy of computed solutions. Results are presented for single rib waveguides and for rib waveguide directional couplers fabricated from III-V semiconductors.
A four-layer Air/PbSe/BaF2/CaF2 structure has been analysed as an opticalwaveguide at a free space wavelength of 3.4 mu m. The structure was found to preserve the unique properties of the more general semiconductor-c...
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A four-layer Air/PbSe/BaF2/CaF2 structure has been analysed as an opticalwaveguide at a free space wavelength of 3.4 mu m. The structure was found to preserve the unique properties of the more general semiconductor-clad opticalwaveguides. The critical values of PbSe thickness that lead to regions of selectively high and low attenuation were accurately determined. Field distribution plots were generated and used extensively to explain these effects. Calculations of the coupling coefficients data indicates that the PbSe-clad opticalwaveguide can be used efficiently in a number of different applications, such as polarisers, optical modulators and IR photo-detectors.
A high-coupling-efficiency interface connecting two opticalwaveguides of large index difference is reported. Both theoretical analysis and an experimental study were performed. High coupling efficiency is achieved by...
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A high-coupling-efficiency interface connecting two opticalwaveguides of large index difference is reported. Both theoretical analysis and an experimental study were performed. High coupling efficiency is achieved by matching the mode profiles in two waveguides as well as connecting the waveguides with an antireflection (AR) section. Analysis shows a coupling efficiency as high as 98% between glass SiO2 and Gao(0.72)Alo(0.23)As-Ga0.59Al0.1As waveguides with an AR section of TiO2. An index difference of 1.8 for the TE(0) mode between these two waveguides is obtained. To implement the glass -SiO2 waveguide with an AR section in the host AlGaAs waveguide, a new quadrilevel photomasking and lift-off process is developed. A coupling efficiency of 83% was measured for the TE(0) mode at the 1.15-mu m wavelength, a very high value considering the large index difference (1.75) between the two waveguides that were connected. The design concept and the fabrication process developed should facilitate efficient integration of low- and high-index waveguides on the same substrate to produce a greater variety of photonic devices and modules.
opticalwaveguides have been formed in natural zircon crystals by MeV helium ion implantation to doses in excess of 4 x 10(16) ions/cm(2). Radiation damage formed by nuclear collisions at the end of the ion range dest...
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opticalwaveguides have been formed in natural zircon crystals by MeV helium ion implantation to doses in excess of 4 x 10(16) ions/cm(2). Radiation damage formed by nuclear collisions at the end of the ion range destroys the crystallinity, reduces the refractive index and acts as an optical barrier to define the waveguide boundary. The amorphised region is stable to at least 800 degrees C but of particular interest is that within the damaged region there is rin apparent refractive index recovery for anneals made near 200 degrees C, even if made subsequent to high temperature annealing. This unusual annealing behaviour is interpreted as evidence for precipitation of metal colloids at 200 degrees C. Experiments to support the model are described.
Singlemode polymer opticalwaveguides are fabricated using fluorinated polyimides. The opticalwaveguides exhibit a low loss of less than 0.3dB/cm parallel to the waveguide plane (TE polarisation) at 1.3 mum, and have...
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Singlemode polymer opticalwaveguides are fabricated using fluorinated polyimides. The opticalwaveguides exhibit a low loss of less than 0.3dB/cm parallel to the waveguide plane (TE polarisation) at 1.3 mum, and have thermal and moisture stability.
The authors show theoretically and experimentally that the propagation direction of bright spatial solitons can be easily controlled by spatially varying the phase across the soliton at its input into the nonlinear me...
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The authors show theoretically and experimentally that the propagation direction of bright spatial solitons can be easily controlled by spatially varying the phase across the soliton at its input into the nonlinear medium, in this case an AlGaAs slab waveguide. The advantages of bright solitons over dark solitons for steerable waveguides are discussed.
The propagation characteristics of a silicon-clad planar diffused opticalwaveguide as a function of wavelength are investigated theoretically. Results for several different waveguide parameters are shown. The results...
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The propagation characteristics of a silicon-clad planar diffused opticalwaveguide as a function of wavelength are investigated theoretically. Results for several different waveguide parameters are shown. The results obtained show that attenuation of the propagating mode in this waveguide is highly dependent on wavelength. Moreover, this attenuation characteristic can be controlled by waveguide parameters such as the refractive index of a buffer layer and a substrate, and the thickness of a silicon-cladding layer. As a result, the silicon-clad planar diffused opticalwaveguides can be used as optical frequency filters.
Singlemode AlGaAs opticalwaveguides at 830 nm have been monolithically fabricated together with ion-implanted E- and D-mode GaAs MESFETs. The waveguide TE and TM propagation losses are as low as 1.5 dB/cm with < -...
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Singlemode AlGaAs opticalwaveguides at 830 nm have been monolithically fabricated together with ion-implanted E- and D-mode GaAs MESFETs. The waveguide TE and TM propagation losses are as low as 1.5 dB/cm with < -25 dB depolarisation. E- and D-mode FETs have V(T) = 0.26 and -0.20 V, and g(m) = 160 and 230 mS/mm, respectively.
A novel technique is presented measuring propagation losses in opticalwaveguides by imaging the scattered intensity on a video camera. This technique requires no special sample preparation and is independent of the l...
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A novel technique is presented measuring propagation losses in opticalwaveguides by imaging the scattered intensity on a video camera. This technique requires no special sample preparation and is independent of the light coupling efficiency to the waveguide.
The realisation of singlemode rib waveguides in silicon-on-insulator (SOI) having a width and height of several micrometres is reported. Measurements at a wavelength of 1.3 and 1.55-mu-m yield waveguide losses below 0...
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The realisation of singlemode rib waveguides in silicon-on-insulator (SOI) having a width and height of several micrometres is reported. Measurements at a wavelength of 1.3 and 1.55-mu-m yield waveguide losses below 0.5 dB/cm and an excellent agreement of the near field intensity distribution with the one predicted by a BPM simulation.
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