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Here we propose an optical fiber sensor capable of simultaneous measurement of liquid level and temperature by utilizing cascaded long-period fiber gratings (LPFGs) inscribed on high-birefringence fiber (HBF) and a Faraday rotator mirror (FRM). Due to the in-fiber Mach-Zehnder interference and birefringence of the HBF, these cascaded LPFGs have polarization-dependent discrete interference spectra, each of which is created within one of the two different attenuation bands obtained in the two orthogonal input polarization states, e.g., linear horizontal polarization (LHP) and linear vertical polarization (LVP). The minimum transmittance dip was selected as a sensor indicator for each interference spectrum obtained for LHP or LVP input signal. To monitor these indicator dips associated with LHP and LVP, referred to as the IDH and IDV, respectively, with one spectral scanning, an FRM was connected to the end of the cascaded LPFGs. Both the IDH and IDV spectrally shifted according to liquid-level or temperature changes and showed very linear responses to them with adjusted R2 values greater than 0.997. The liquid-level sensitivities of the IDH and IDV were measured as approximately −37.29 and −121.08 pm/mm in a liquid-level range of 0 to 55 mm, respectively. The temperature sensitivities of the IDH and IDV were measured as ˜28.79 and ˜218.21 pm/°C in a temperature range of 30 to 60 °C, respectively. Owing to their linear and independent responses to liquid level and temperature, our sensor can perform temperature-independent liquid-level measurement using their pre-determined liquid-level and temperature sensitivities, even if both liquid level and temperature change simultaneously.

This paper represents the study of magneto-optic sensor behavior using terbium-doped glass (TDG) rod as Faraday rotator. The performance of photo-detector is affected by different types of noises present in the optical path/medium. An artificial neural network has trained for cancelation of noise present in optical signal. The trained network has been able to perform de-noising of optical signal with mean of error in network to 0.44%.

We propose a universal scheme for the construction of a device for arbitrary-to-arbitrary polarization transformation, which consists of two quarter-wave plates and two Faraday rotators. Using this device, one can continuously change the retardance and the rotation angle simply by changing the magnetic fields in each Faraday rotator.

A kind of Michelson interference structure is used to improve the round-trip phase correction method and realize the feedback phase stabilization control. In the system, the phase shifter pre-compensation control, 1/4 wave plate debirefringence and Faraday rotator de-polarization sensitivity effectively avoid the polarization fading phenomenon existing in photoelectric detection by external factors, and realize the signal arm carrying phase jitter. At the same time, the AOFS driven by the intermediate frequency signal realizes the construction of the reference arm of the interferometer. Through photoelectric detector to beat frequency of two arms mutual interference signal, the beat frequency signal and intermediate frequency reference signal phase matching, can get the phase perturbation of optical fiber transmission system, the phase discriminator output signal processing can be used as the bias current of SOA control signal, realize the purpose of the feedback control signal phase, has solved the traditional approach to the problem of high frequency signal phase is not convenient to monitor.

The utilization of a bismuth-substituted iron garnet as a magnetooptic Faraday rotator (MOFR) has been reported for all-optical networking purposes as well as for other applications. Our measurements and observations demonstrate that the MOFR saturates once a significantly large magnetic field (>225 G) is applied. After the applied magnetic field enters the saturation region, the material’s magnetic domains can become pinned at intermediate levels of magnetization. Pinning in this form has not been reported nor well studied for this application. In this paper, a method to detect and describe anomalous pinning in terms of Faraday rotation is presented. Measurements on the changes in the state of polarization that a pinned material produces are examined. This paper will also present practical methods for unpinning the MOFR material, which are traditionally considered to be challenging.

A three-degrees-of-freedom measurement system based on the Faraday effect is proposed for simultaneously measuring two-dimensional straightness errors and their position. Thanks to the Faraday effect of the Faraday rotator, the direction of a linearly polarized beam can be changed by 90° when the linearly polarized beam passes through the same Faraday rotator back and forth twice. A novel optical configuration is designed that can integrate the interferometry and position-sensitive detection technology ingeniously and put their advantages together. The measurement principle is described in detail. The influence of angle error of the semitransparent mirror on straightness measurement is discussed. To verify the feasibility of the proposed system, the experimental setup for measuring three degrees of freedom was constructed, and a series of experiments were carried out.

Tb 3Sc 2Al 3O 12 (TSAG) is a paramagnetic insulator which, in spite of its congruent nature and excellent magneto-optical properties as Faraday rotators for optical isolators (OIs), cannot be industrially produced. The reason is that its lattice structure is so stressed that single crystals easily crack upon cooling after growth or during the cutting process. By the incorporation of a small amount of Lu, it has been demonstrated that the stress in the structure can be effectively released, and, therefore, the crystal cracking can be avoided. This has enabled the substitution of standard Tb 3Ga 5O 12 (TGG), achieving better high-power performance and compacter OIs. In this study, the charge state and the lattice site location of Lu as well as Y dopants in TSAG are investigated by X-ray Absorption Near Edge Structure and Extended X-ray Absorption Fine Structure Analysis. Measurements on single crystal and powdered samples indicate that both dopants are incorporated in the 3+ charge state and substitute predominantly in the dodecahedral Tb-site ( >87.5%), while a minor fraction is found in the octahedral Sc-site.

The Faraday rotation effect describes the rotation of the plane of polarization of a linearly polarized wave in an infinite gyromagnetic medium or circular waveguide. This chapter includes a definition of the gyrator network and the description of some common ferrite devices in round waveguides based on Faraday rotation effect, such as Faraday rotation isolators, circulators, nonreciprocal phase‐shifters, and amplitude modulators and switches. Three and four‐port circulators based on turnstile junctions are also described. The simplest component that illustrates the nonreciprocal property of a Faraday rotator is the gyrator circuit. One application of the gyrator network is in the construction of the four‐port differential phase‐shift circulator. An important application of a Faraday section is in connection with the realization of a four‐port Faraday rotation circulator. The geometry of a practical Faraday rotation section usually consists of a ferrite rod inside a circular waveguide filled by a suitable dielectric material.

In this paper, output characteristics of single-longitudinal-mode Ho: YLF ring laser are firstly investigated in double corner cubes configuration. Single-longitudinal-mode laser output is realized by a faraday rotator and a half-wave plate, and an F-P etalon is inserted into the cavity to realize wavelength tuning. The principle of unidirectional operation of the Ho: YLF ring laser with double corner cubes is firstly analyzed with the method of optic matrix and transition matrix. A highest single-longitudinal-mode power of 733 mW at 2065.68 nm is achieved and the slope efficiency is 12%. The tunable range is about 238 GHz and M2 factor is 1.21. The results show that the single-longitudinal-mode Ho: YLF ring cavity with double corner cubes is a potential way to improve the misalignment sensitivity.

An optical fiber sensor based on the single-mode/no-core/single-mode (SNS) core-offset technology along with a Faraday rotator mirror structure has been proposed and experimentally demonstrated. A transverse optical field distribution of self-imaging has been simulated and experimental parameters have been selected under theoretical guidance. Results of the experiments demonstrate that the temperature sensitivity of the sensor is 0.0551 nm/°C for temperatures between 25 and 80 °C, and the correlation coefficient is 0.99582. The concentration sensitivity of the device for sucrose and glucose solutions was found to be as high as 12.5416 and 6.02248 nm/(g/ml), respectively. Curves demonstrating a linear fit between wavelength shift and solution concentration for three different heavy metal solutions have also been derived on the basis of experimental results. The proposed fiber-optic sensor design provides valuable guidance for the measurement of concentration and temperature.

Enhanced Faraday rotation in a new type of magneto-plasmonic structure with the capability of Fano resonance, has been reported theoretically. A magneto-plasmonic structure composed of a gold corrugated layer deposited on a magneto-optically active layer was studied by means of Lumerical software based on finite-difference time-domain. In our proposed structure, plasmonic Fano resonance and localized surface plasmon have induced enhancement in magneto-optical Faraday rotation. It is shown that the influence of geometrical parameters in gold layer offers a desirable platform for engineering spectral position of Fano resonance and enhancement of Faraday rotation.

Two defective conjugated magneto active photonic crystals are proposed in this paper for fabrication of Faraday rotators. Optical features of the suggested structures are studied using 4 × 4 transfer matrix method and taking into consideration of the couplings of polarization states. Band structure of the crystals including generation of stop bands and resonant modes localizations are studied by exploring the dependence of the crystals' transmittance on the period number of the layers. It is shown that desirable responses are obtained by just very low number of periods. Furthermore, optical anisotropy of the crystals is considered to be purely magnetic field-induced. Then in addition to studying the dependencies on structural parameters, connection between wave incident angle and magneto-optical effects (Faraday rotations and changes of the ellipticity angle) are discussed in detail. Results clearly show the ease of tunability of the structures' responses in this way which is of prime importance from experimental point of view. Furthermore, the proposed structures offer remarkable Faraday rotation angles when transmittance amounts remain high enough simultaneously. Thus it seems that these crystals might be useful for fabrication of polarization dependent sensor/transducers based on Faraday rotators which are vital elements in development of integrated circuits as well as imaging systems.

This article describes full analysis of a novel transverse electric (TE) to transverse magnetic (TM) polarization rotator based on mode interference utilizing finite element method. The core, substrate, and cladding of the polarization rotator are in the hybrid technology of InGaAsP and SiO2 materials. Effect of several parameters such as core's refractive index, width to height ratio of the polarization rotator, and incident light's wavelength on polarization conversion length, polarization efficiency, polarization extinction ratio, and rotation angle were investigated. Simulation results revealed that the rotation length was less than 1 μm, while the polarization conversion efficiency of 90%, polarization extinction ratio of 15 dB, and maximum rotation angle of 85° at 1.55 μm wavelength can be achieved.

Interferometers are essential elements in classical and quantum optical systems. The strictly required stability when extracting the phase of photons is vulnerable to polarization variation and phase shift induced by environment disturbance. Here, we implement polarization-insensitive interferometers by combining silica planar light-wave circuit chips and Faraday rotator mirrors. Two asymmetric interferometers with temperature controllers are connected in series to evaluate the single-photon interference. Average interference visibility over 12 h is above 99%, and the variations are less than 0.5%, even with active random polarization disturbance. The experiment results verify that the hybrid chip is available for high-demand applications like quantum key distribution and entanglement measurement.

Magneto-optical glass materials with large Verdet constants at 2 μm have attracted increasing attention due to the significant advances of novel lasers operating at this wavelength region. In this paper, 13Al2O3-21B2O3-35.4SiO2-(30.6-X)Er2O3-XDy2O3 glasses have been synthesized, and their physical, optical, and magneto-optical properties were studied for making Faraday devices at 2 μm. A Verdet constant of as high as −5.9 rad/(T*m) at 1950 nm was measured with a 13Al2O3-21B2O3-35.4SiO2-30.6Dy2O3 glass. The temperature difference between crystallization and glass transition of 150 °C and the synthesis temperature of below 1500 °С make this glass very promising for making magneto-optical devices for 2 μm applications.

High quality PrF3 crystal was successfully grown by the temperature gradient technique (TGT). The magneto-optical properties of PrF3 crystal were systematically investigated in the UV-VIS-NIR region. The advantage of PrF3 over CeF3 and TGG is its transparency in deep-UV region down to 258 nm. The dispersions of Verdet constant of PrF3 and TGG crystals in VIS-NIR region are similar. The Verdet constant of PrF3 crystal can theoretically increase from 677.93 rad T−1•m−1 at 300 nm to 967.53 rad T−1•m−1 at 270 nm. The CeF3 and TGG crystals aren't transparent in this region. Therefore, PrF3 crystal is the promising candidate for use as a Faraday rotator for optical systems operating below 300 nm.

The magneto-optic rotation enhanced by plamonic resonance brought a new method in the research of magnetoplasmon and magneto-optical devices. To further the availability of this method, the Faraday effect on embedded nano-gratings with Bi-substituted yttrium iron garnet substrate is investigated here to achieve bi-directional rotation enhancement selectively. The surface of the simulation structure is designed as 1-D gratings to excite extraordinary optical transmission, and the transmitted light is rotated in the magneto-optic (MO) material. It is found that the characteristic of the bi-directional Faraday rotation enhancement can be greatly influenced by the embedding depth of the metal strips in the MO material. According to this, without changing the applied magnetic field or turning over the MO material, the selectively enhanced Faraday rotation is produced along two opposite directions. Moreover, by optimizing the thickness of metal, a great improvement of figure of merit is obtained. Finally, in the same wavelength regime, the properties of the structure are contrasted when the metal is set to be gold or silver, respectively. This letter provides a useful thought in magnetoplasmon studies, and can be used to fabricate many magneto-optical devices.

The crystals of magnesium sulphite hexahydrate (MgSO 3 ·6H 2 O) belong to point group C 3 (no center of symmetry). They possess gyrotropy and nonlinear optical properties. The refractive index n o and n e , the angle of Faraday rotation φ(λ), the Verdet constant V(λ), the magneto-optic anomaly factor γ(λ) and the density of oscillators N of MgSO 3 ·6H 2 O single crystals have been studied in the present work. The investigations were carried out in the spectral range 300 – 800 nm with linear polarized light E ⊥ c , E | | c ( c is the optical axis of MgSO 3 ·6H 2 O) propagated in the direction ( 10 1 0 ) .

An investigation of the drift caused by the Faraday effect in a dual-polarization interferometric fiber optic gyroscope (IFOG) is presented. Both theoretical analysis and experimental results indicate that the Faraday effect phase drifts in two orthogonal polarizations of polarization-maintaining fiber always have opposite polarities that can be compensated effectively. When the interference signals of the two orthogonal polarized light waves are added up, the bias stability of the IFOG is improved significantly. This study is promising for reducing the drift of IFOG caused by the Faraday effect.

Super full dense (TbxY1-x)3Al5O12 (x=0.5~1.0) ceramics with optical grade (pore-free) were successfully produced by solid-state reaction between Tb4O7 and Al2O3 raw powders. Transparent sintered bodies were obtained by sintering at 1720°C for 5 hr in vacuum furnace. By additional HIP treatment, optical scattering centers were effectively removed, and finally the optical quality of the sintered bodies was improved to optical grade. Optical loss of the obtained samples at 1064nm was approximately 0.1%/cm, and optically inhomogeneous parts were not observed inside the materials. Gaussian mode laser beam quality was not deteriorated after passing through the sample. Transmitted wavefront distortion inspected by interferometry was as excellent as λ/12. Verdet constant increased with an increase of Tb content in the garnet composition. When x=1.0, the Verdet constant was 307, 196 and 60 rad.T−1.m−1 for 532, 633 and 1064nm, respectively at each measuring wavelength. These values were about 1.5 times higher than that of the commercially available TGG (Tb3Ga3O12) crystal. Insertion loss of the produced (Tb0.6Y0.4)3Al5O12 and TAG ceramics at 1064nm was 0.01dB and 0.05dB, respectively, and extinction ratio was 39.5dB and 40.3dB, respectively. These properties were superior to that of the commercial high quality TGG single crystal (insertion loss: 0.05dB, extinction ratio: 35.0dB). This article is protected by copyright. All rights reserved.

The influence of the linear birefringence on magneto-optical property measurement for optical fibers is investigated theoretically and experimentally. The evolution of polarization in fibers is simulated by the Jones matrix. To verify this theoretical model, a magneto-optical system is built to measure the input azimuth, output azimuth and ellipticity. The Faraday rotation of spun fibers with different pitches is measured. The Verdet constant increases, while the linear birefringence decreases as the pitch becomes smaller. For spun fibers with 1 mm pitch, the Verdet constant can be enhanced by about 20.7% at 660 nm, compared with that of the unspun fiber. The results indicate that smaller linear birefringence can provide more accurate Faraday rotation measurement.

A self-designed probe and a feedback control scheme based on the Michelson interferometer with a 3 &times, 3 fiber coupler are proposed. A 45&deg, Faraday rotator is built into the self-designed probe, and a feedback control scheme is used to judge the direction of increase or decrease for the phase compensation, so as to solve the problems of polarization and phase fading. In addition, a result-normalized method is applied in a micro-vibration measurement experiment. The experimental interferometer system achieves a high frequency of 1 MHz micro-vibration. The normalized results keep stable with a maximum deviation from the mean of 1.9% when the power of light reflected back into the self-designed probe is altered. Applied research is carried out by detecting the displacement due to a photoacoustic wave. Therefore, the experimental interferometer system is available for the practical application of micro-displacement measurements, noncontact high-frequency detection, and point-by-point image scanning in biological tissue.

In this paper, we propose an optical comb filter based on a polarization-diversity loop structure, whose two transmission channel spacings (TCS's) can be alternately switched between two principal axes of the filter by controlling waveplates contained in the filter. The proposed filter consists of a polarization beam splitter (PBS), three half-wave plates (HWPs), one Faraday rotator (FR), and two polarization-maintaining fiber (PMF) segments with different lengths (L and 2L) and equal birefringence (B). As the PMF segments are utilized as birefringence elements, the TCS of the filter is determined by the product of their effective length Le and birefringence B. For an input signal introduced into each principal axis of the filter, Le can be the sum of or difference between the two lengths (L and 2L) of the two PMF segments, that is, L or 3L, resulting in a TCS of S1 or S₂, respectively, according to angular combination of the orientation angles of the three HWPs. At a specific set of the three HWP angles, the proposed filter can create two sinusoidal transmittance functions with different TCS's (S1 and S₂) at the two principal axes, respectively. Also, the two TCS's (S1 and S₂) are switchable with each other depending on three HWP angles for each principal axis. With the fabricated filter, the flexible switching between S1 and S₂ could be successfully implemented for two orthogonally polarized input signals aligned along the two principal axes of the filter by properly controlling the three HWPs, without any modification of the filter configuration.

Compared to conventional waveguides or strips to make circulators or isolators, their ease of processing and low loss characteristics can be applied to isolation devices in quasi-optical systems. It can realize the separation function of the transceiver channel. In this paper, the structure of a single-layer Faraday rotator is proposed. The operating frequency band is 90 GHz, and the 45° deflection of the electric field direction is realized. The simulation is carried out in CST. The results are in line with expectations. The simulation verifies the influence of the thickness of the Faraday rotator and the applied magnetic field on the deflection angle.

We experimentally study data suppression characteristics of a semiconductor optical amplifier with a Faraday rotator mirror used for wavelength-reuse WDM-PON. Bidirectional transmission over 10 km assisted by spectral trimming using a Fabry-Perot etalon is demonstrated.

A newly designed six-port optical circulator with a small aperture of Faraday Rotator is proposed. To verify the feasibility, a prototype was assembled and tested. This design should have an application potential in related applications.

In this paper, we propose an optical comb filter based on polarization-diversified-loop (PDL) configuration that offers switching operation between dual transmission spectra with different channel spacings by controlling the state of polarization (SOP) of input light with orthogonal relation. As shown in Fig. 1(a), the PDL-based filter consists of a four-port polarization beam splitter, combination of three half-wave plates (HWPs), one Faraday rotator (FR), and two bow-tie polarization-maintaining fiber (PMF) segments with different lengths (L and 2L) and equal birefringence (B). By controlling an input polarizer located before port 1 of the PBS, ASE light is linearly polarized such as linear horizontal polarization (LHP) and linear vertical polarization (LVP) components which propagate along clockwise (CW) and counterclockwise (CCW) directions in the PDL loop, respectively [1]. Fig. 1(b) represents principal optical paths (CW and CCW paths) divided by orthogonal SOPs of input light. Generally, when PMF segments are utilized as birefringence elements, channel spacings (Δλ) of output transmission spectra are determined by the product of their effective length (L eff ) and birefringence expressed as the equation Δλ=λ2/B-L eff where λ is wavelength in vacuum. In the proposed filter, the effective length of the two PMF segments can be the sum of or difference between their two lengths according to their angular combination of the orientation angles of the three HWPs for orthogonal input SOPs. That is, by properly adjusting angle sets of the three HWPs, the proposed filter can create two sinusoidal transmittance functions with different channel spacings determined by LB and 3LB for orthogonal input SOPs of LHP and LVP, and vice versa. According to theoretical analysis, the resulting filter transmittance is the algebraic sum of two sub transmittances along the CW and CCW paths calculated by Jones matrix formulation, given by (1-a)t CW + at CCW where a is a splitting ratio of optical power coupled to x- and y-axes at the PBS and ranges from 0 to 1 for LHP and LVP input components, respectively. Fig. 1(c) shows the switching operation between dual transmission spectra with different channel spacings for orthogonal input signals at different angle set of three HWPs, measured in a wavelength range from 1548 nm to 1552 nm. In the upper figure of Fig. 1(c), two measured transmission spectra with channel spacings of ∼0.75 nm and ∼0.25 nm were obtained for LHP and LVP input SOPs, indicated as blue solid and red dotted lines, respectively. In a similar manner, two transmission spectra with channel spacings of ∼0.25 nm and ∼0.75 nm were achieved for LHP and LVP input SOPs, indicated as blue solid and red dotted lines in the lower figure of Fig. 1(c), respectively. Consequently, the fabricated filter could demonstrate the input polarization-controlled switching operation between two transmission spectra with different channel spacings of −0.25 nm and −0.75 nm without modifying the filter structure.

The development of magnetic photonic crystals (MPC) has been a rapidly evolving research area since the late 1990s. Magneto-optic (MO) materials and the techniques for their characterization have also continually undergone functional and property-related improvements. MPC optimization is a feature-rich Windows software application designed to enable researchers to analyze the optical and magneto-optical spectral properties of multilayers containing gyrotropic constituents. We report on a set of computational algorithms which aim to optimize the design and the optical or magneto-optical spectral analysis of 1D MPC, together with a Windows software implementation. Relevant material property datasets (e.g., the spectral dispersion data for the refractive index, absorption, and gyration) of several important optical and MO materials are included, enabling easy reproduction of the previously published results from the field of MPC-based Faraday rotator development, and an effective demonstration-quality introduction of future users to the multiple features of this package. We also report on the methods and algorithms used to obtain the absorption coefficient spectral dispersion datasets for new materials, where the film thickness, transmission spectrum, and refractive index dispersion function are known.

A polarization-insensitive recirculating delayed self-heterodyne method (PI-RDSHM) is proposed and demonstrated for the precise measurement of sub-kilohertz laser linewidths. By a unique combination of Faraday rotator mirrors (FRMs) in an interferometer, the polarization-induced fading is effectively reduced without any active polarization control. This passive polarization-insensitive operation is theoretically analyzed and experimentally verified. Benefited from the recirculating mechanism, a series of stable beat spectra with different delay times can be measured simultaneously without changing the length of delay fiber. Based on Voigt profile fitting of high-order beat spectra, the average Lorentzian linewidth of the laser is obtained. The PI-RDSHM has advantages of polarization insensitivity, high resolution, and less statistical error, providing an effective tool for accurate measurement of sub-kilohertz laser linewidth.

Deep-ultraviolet (DUV) light sources are critical owing to their high photon energies and small diffraction limits, and synthetic quartz glass (SQ) is suitable for the Faraday rotators of DUV light. The Verdet constant in SQ was evaluated within the wavelength range of 190–300 nm. In addition to a high Verdet constant over the DUV region, this material exhibits a high transmittance without transitional absorption bands. The Verdet constants were found to be 70.1 rad/(T·m) at 193 nm, which is the shortest observed wavelength for silica glass. SQ glass has excellent structural properties; thus, it is suitable as a DUV Faraday rotator for high-average-power optical isolators.

The Faraday rotator is an important component used to separate the launching and receiving electromagnetic waves in the transmission line for millimetre wave radar systems. It has lower insertion loss, higher isolation and power capabilities as compared with the waveguide isolators. In this study, a HE11 mode corrugated horn for the microwave performance measurement of a Ka-band Faraday rotator was designed, fabricated and cold tested. The corrugated horn has a high conversion efficiency of above 99% over a bandwidth of 4 GHz. It is short in length, at 44 mm and produces a well-formed linearly polarised HE11 mode. The polarised wave has a well-defined primary lobe and a −26.7 dB side-lobe and also achieves a cross-polarisation of −57.4 dB. The measured microwave reflection coefficient of the corrugated horn was in good agreement with simulation results and the back-to-back transmission coefficient is above −0.7 dB over a bandwidth of 7 GHz for a distance of 2 mm between the horns. Except high conversion efficiency, broad bandwidth, low side-lobes and low cross-polarisation, this corrugated horn is short, simple and suitable for the microwave measurement of Faraday rotator.

The extraordinary optical transmission and Faraday effects of the bilayer heterostructure consisting of a metallic film perforated with subwavelength hole arrays and a uniform dielectric film magnetized perpendicular to its plane were systematically studied by three-dimensional finite-difference time-domain method. Results of the calculation found that for the magneto-plasmonic crystals under polarized incident light with transverse magnetic mode, the resonant transmittance reached 36.9%, the Faraday rotation acquired 1.216°, and the ellipticity got a positive value of 0.840. The value of Faraday rotation and ellipticity is respectively 15.2 and 93.3 times enhancement of the 0.08° and −0.009 of the bare BIG film at the wavelength. In the transverse electric mode, the Faraday effects of the systems also had a large enhancement in contrast to the bare magnetic film. The magneto-optical effects of the systems could be manipulated by polarization mode of incident light, geometry of perforated subwavelength hole arrays, and thickness of metallic and magnetic films. Evolution of the magneto-optical properties on the structural parameters was also analyzed. Possible mechanisms underlying the extraordinary phenomena were profoundly discussed. All these results indicated that the systems could find potential applications in magneto-optical devices such as data storages, sensors, and telecommunications.

We theoretically investigated an enhancement of the magneto-optical Faraday rotations along with large transmittance in two multilayer structures. The shifts of the Faraday rotation peaks are more obvious than the transmittance peaks when the grating period is changed, which is beneficial to acquire the large Faraday rotation and transmittance. The Faraday rotation of tri-layer system is five times larger than the bilayer system, and the Faraday resonance peak can be mediated by changing the refractive index or thickness of the additional nonmagnetic dielectric layer (NDL) layer. These results are important for applications in highly integrated optoelectronic and magneto-optical devices.

The inverse Faraday effect in iron garnet films subjected to femtosecond laser pulses is experimentally investigated. It is found that the magnitude of the observed effect depends nonlinearly on the energy of the optical pump pulses, which is in contradiction with the notion that the inverse Faraday effect is linear with respect to the pump energy. Thus, for pump pulses with a central wavelength of 650 nm and an energy density of 1 mJ/cm2, the deviation from a linear dependence is as large as 50%. Analysis of the experimental data demonstrates that the observed behavior is explained by the fact that the optically induced normal component of the magnetization is determined, apart from the field resulting from the inverse Faraday effect, by a decrease in the magnitude of the precessing magnetization under the influence of the femtosecond electromagnetic field.

We present the design and theoretical characterization of a magnetoplasmonic Faraday rotator for active polarization control in integrated plasmonics. By incorporating bismuth-substituted yttrium iron garnet (Bi:YIG) into a unique hybrid ridge–plasmonic waveguide structure, we effectively overcome the phase-matching limitations between photonic TE and plasmonic TM modes, and hence attain efficient Faraday rotation within a plasmonic device. The device provides 99.4% polarization conversion within a length of 830 μm, while the two modes exhibit propagation lengths in excess of 1 mm. This versatile optical building block can be operated with either a TE or TM input, making it ideal for polarization switching and polarization division multiplexing. Additionally, a buried Ag transmission line under the waveguide facilitates high-speed active polarization modulation by generating transient magnetic fields and modulating the Bi:YIG magnetization. We show that with these transient fields and an external static b...

We demonstrated an optical fiber refractive index (RI) sensor based on an in-fiber Michelson interferometer (MI), which is fabricated by splicing a Faraday rotator mirror (FRM) to a singlemode-thin core-singlemode (STS) optical fiber interferometer. From our experiments, it can be found that thus a FRM as reflector can eliminate the polarization random fluctuation of interference spectrum, which makes the sensor exhibit a high stability. Core to core splicing of thin core to standard single mode optical fibers and high reflectivity mirror of FRM can reduce the optical power loss and improve the fringe contrast of sensor spectrum. Both high stability and low power loss are very important in such kinds of reflection interference spectrum modulation and high resolution sensors. This sensor wavelength and intensity RI sensitivity is −48.858 nm/RIU and −6.548 dB/RIU at the liquid RI from 1.38 to 1.435, respectively. The temperature sensing performance of this sensor is also studied, the sensor wavelength versus temperature sensitivity is 66.18pm/ °C and intensity hardly change with temperature, which means that the temperature cross sensitivity can be eliminated when intensity modulated, and this sensor also has compact size, simple structure, easy fabrication and good repeatability.