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A study was conducted to analyze the magnetic characteristics of bubble-type Bi-YIG films supporting large out-of-plane anisotropy in different stages of the separation process. Experimental results indicated that implantation minimizes he perpendicular anisotropy field because of an increased residual strain. Findings also showed that upon detachment, the perpendicular anisotropy of the sample was nearly fully restored to its original value.

Fabrication of very small magneto-optic devices is performed using high-coercivity planar-magnetization film magnets and bismuth-substituted yttrium iron garnet film techniques. High performance wave-guide magneto-optic isolators are used for the preparation of integrated optical circuits. The instrument used in this technique operates at 1.55 micrometer wavelength.

The adsorption, thermal chemistry, and photoreaction dynamics of methyl iodide on the (2*2) magnetite termination of natural single-crystal hematite are investigated by various methods, which include temperature-programmed desorption. The methyl iodide thermal desorption spectra, taken after dosing the (2*2) surface at 100K with CH3I, show a multiple-peak coverage-dependent behavior, consistent with the presence of several distinct adsorbed phases.

We analyze the structure of the optical field emerging from a superposition of two soliton-like pulses with different frequencies and arbitrary phase-shift between them, and show that the optical output contains either symmetric or antisymmetric two-soliton states. Furthermore, we study numerically the dynamics of these emerging two-soliton states under the influence of perturbative effects that are important for optical communications systems: frequency-sliding filters, third-order dispersion, and intrapulse Raman scattering. [ABSTRACT FROM PUBLISHER]

We survey the properties of photonic crystal fibers with elliptical air holes, examining mode shapes, birefringence, group velocity walkoff and dispersion, and cutoff conditions. We find new types of behavior for each quantity and demonstrate the possibility achieving large birefringence with zero walkoff in the single-mode regime. We show that the dispersive properties of the vector modes are closely tied to those of the so-called fundamental space filling modes, and that at long wavelengths, the fibers exhibit a single-polarization single-mode regime of propagation without the presence of material anisotropy [ABSTRACT FROM PUBLISHER]

We investigate enhancement of magnetooptical rotation in periodic magnetic garnet thin-film stacks with defects using a combination of coupled-mode theory and matrix calculations. We prove that a combination of high rotation per unit length and high output is unattainable for a symmetric grating with a single central defect. We demonstrate that the addition of a second defect introduces sufficient degrees of freedom to allow high transmission for a much larger range of rotation angles than was previously possible. We present a number of designs with emphasis an achieving 45° rotation in very short propagation lengths [ABSTRACT FROM PUBLISHER]

We perform a theoretical study of enhancement of magnetooptical rotation on reflection of light from a periodic system with a defect. Using calculations based on a coupled mode approach and the transfer matrix method we demonstrate that an asymmetric placing of a single defect allows arbitrary Kerr rotations with better than 99% reflectivity from very short devices [ABSTRACT FROM PUBLISHER]

Existing algorithms for bidirectional optical beam propagation proposed to simulate reflective integrated photonic devices do not propagate evanescent fields correctly. Thus inaccuracy and instability problems can arise when fields have significant evanescent character. We propose complex representations of the propagation operator by choosing either a complex reference wave number or a complex representation of Pade approximation to address this issue. Therefore correct evolution of both propagating waves and evanescent waves can be simultaneously realized, significantly reducing the inaccuracy and instability problems. Both test problems and practical problems are presented for demonstration [ABSTRACT FROM PUBLISHER]

A novel 1×4 coupler multiplexer permutation switch (CMPS) is proposed for applications in wavelength-division-multiplexing (WDM) optical networks. The structure of the CMPS integrates the multiplexing and switching functions into a single compact device. It consists of a single-mode/multimode-waveguide grating-assisted, backward-coupler multiplexer followed by a 1×4 digital optical switch (DOS). The specific design uses an InP-based 1×4 CMPS with InGaAsP-InP multiple-quantum-well (MQW) DOS. The calculated values of crosstalk for the coupler multiplexer and the DOS are <-25 dB and -23 dB, respectively, giving an overall crosstalk <-21 dB for channel bandwidths of 10-13 GHz. The device channels are unequally spaced, which reduces unwanted four-wave mixing (FWM), but are fitted to the ITU standard wavelength grid [ABSTRACT FROM PUBLISHER]

Expressions for the modulation bandwidth and drive voltage for optical resonator-based modulators are presented. A comparison with lumped element Mach-Zehnder (MZ) modulators and with traveling wave MZ modulators is presented [ABSTRACT FROM PUBLISHER]

When the alternating direction implicit-finite difference time domain method (ADI-FDTD) is applied to simulating photonic devices, full efficiency can not be achieved if reasonable accuracy is to be kept, due to numerical errors such as numerical dispersion. A simple modification to ADI-FDTD is proposed by calculating the envelope rather than the fast-varying field, so that errors are minimized. A factor of two-five in speed can usually be gained while retaining the same level of accuracy compared with conventional FDTD. The efficiency and the accuracy of this improved approach is demonstrated on several problems, from simple waveguide structures to complex photonic crystal structures [ABSTRACT FROM PUBLISHER]

Crystal ion slicing was used in conjunction with conventional annealed proton exchange in Z-cut LiNbO3 to result in prepatterned microns-thick single-crystal LiNbO3 films with channel guides and a measured waveguide propagation loss of 0.2-0.7 dB/cm. Full optical circuit transfer, including a buffer layer and a patterned metal electrode structure for active control was demonstrated [ABSTRACT FROM PUBLISHER]

Optical waveguides fabricated on a yttrium iron garnet (YIG) substrate are integrated onto a semiconductor surface by using ridge waveguides patterned onto a prefabricated recess in the YIG surface. The recess separates the waveguides from the semiconductor substrate with an air-gap. This structure makes it possible to avoid coupling light within the YIG waveguides into the semiconductor substrate which has a higher refractive index. The excess optical loss due to the coupling can be as low as 0.1 dB/cm with a 1-μm-wide air-gap. The calculated coupling loss is confirmed by comparing the guided TE and TM modes [ABSTRACT FROM PUBLISHER]

In this letter, we have designed and fabricated low-loss ultrasmall corner mirrors and T-branches on thin silicon-on-insulator material system. The measured performance of the devices agrees with simulations using finite-difference time-domain calculations. These devices demonstrate the potential of this high-refractive-index-contrast material system for high-density planar optical integrated circuits [ABSTRACT FROM PUBLISHER]

We have fabricated a bicell detector consisting of a single freestanding film of single-crystal lithium niobate (LiNbO3) 10-μm thick, having two adjacent domains of opposite spontaneous polarization, and hence, two adjacent pyroelectric detector regions of equal and opposite sensitivity. The film was created by applying the process of crystal ion slicing and electric field poling (domain engineering) to a Z-cut LiNbO3 wafer. The detector's noise equivalent power was 6 nW·Hz-1/2 at 16 Hz, and the ambient temperature-dependent variation of the detector's response near room temperature was 0.1% K-1. The acoustic noise sensitivity measured at 100 Hz was -24 dB relative e to that of a single-domain detector [ABSTRACT FROM PUBLISHER]

Reports on fabrication and characterization of the first zeroth-order half-wave plates of LiNbO3 obtained by crystal ion slicing (CIS). Polarization rotation was demonstrated in 10-μm-thick freestanding LiNbO3 films with 30-dB conversion ratios and negligible material loss. Polarization-independent performance was demonstrated in a hybrid-optic device comprising a CIS wave plate integrated with single-mode silica-based channel waveguides [ABSTRACT FROM PUBLISHER]

Microwave-optical velocity matching and 50 Ω impedance matching are difficult to achieve with LiNbO3 traveling wave modulators. We perform a detailed study (simulations) of the microwave and optical performance characteristics for modulators using thin layer (few micrometers), X-cut LiNbO3 and find significant improvements in velocity and impedance matching together with a lower V πL [ABSTRACT FROM PUBLISHER]

A polarization-independent waveguide optical isolator based on nonreciprocal interference is proposed. The design uses simultaneous TE and TM nonreciprocal phase shifts obtained from geometric asymmetry in horizontal and vertical axes of waveguide cross section along with opposing transverse and vertical magnetic fields in interferometer arms. A design to achieve such an isolator is described. Both TE and TM nonreciprocal phase shifts comparable to the theoretical counterparts have also been experimentally observed from a single waveguide. [ABSTRACT FROM PUBLISHER]

Photonic crystals containing defects produce enhanced Faraday rotation but existing designs have low intensity output. We show that designs with two-defects possess sufficient freedom to attain high transmission over a large range of rotation angles in very short lengths. We optimize such systems for 45° rotation in optical isolators [ABSTRACT FROM PUBLISHER]

A single-section, compact, passive polarization converter has been designed and fabricated on GaAs-AlGaAs. The device uses an optimized waveguide structure with angled-facets to obtain 90°-polarization rotation in a single section; this waveguide structure eliminates the need for longitudinal variation and hence avoids any section-to-section coupling losses. A transverse electric (TE) to transverse magnetic (TM) polarization conversion of 96% is achieved for a conversion length of ≈720 μm [ABSTRACT FROM PUBLISHER]

Recently proposed tapered MMI devices have been shown to allow for substantial reductions in device geometries, but as of this time such ultracompact devices have not been realized. The fabrication and testing of a series of parabolically tapered 3-dB 2×2 MMI devices have been accomplished in the InP-InGaAsP double heterostructure system. The results validate previous predictions and yield device geometries about 40% smaller than the shortest previous 3-dB 2×2 MMI device. The measured splitting ratios of these devices are compared to the results of numerous beam propagation method simulations, based on the finite-difference method, and good correlation is obtained [ABSTRACT FROM PUBLISHER]

A novel approach to the bidirectional beam propagation method, which can treat multiple dielectric interfaces, is developed and implemented using iterative methods. Comparisons with two previously published results demonstrate its accuracy, as well as its efficiency in computation time and memory. Finally, its capability in simulating and designing complex structures is also demonstrated via a three-channel add-drop multiplexer [ABSTRACT FROM PUBLISHER]

A new technique for forming nonperipheral cleaved facets on GaAs epilayers for hybrid optical integration is demonstrated. Local photoelectrochemical etching is used to form an undercut region under the epilayer structure. The undercut region is then cleaved by subsequent ultrasonic agitation. Undercut widths of 70-170 μm±5 μm are obtained at a bias voltage of 2 V and laser powers of 200-600 μW. Optical measurements show that these facets have minimal (0.4 dB) excess loss. A thin-film polarizer is inserted into the groove to test facet performance; the test shows a minimal degradation of the extinction ratio (<0.3 dB) over its free-space counterpart [ABSTRACT FROM PUBLISHER]