Beam Splitting Ratio Research Articles

Low-cost 1×2 plastic optical beam splitter using a V-type angle polymer waveguide for the automotive network

The design, fabrication, and characteristic of the plastic optical fiber (POF), beam splitter, for the automotive network, has been demonstrated. The fabricated 1×2 POF beam splitter consisted of a poly(methylmethacrylate) (PMMA) core, which had a structure of circular waveguide and a diameter of 0.98 mm, UV curable epoxy (PC-414) clading of 0.02 mm thickness, and three POF pigtails with multimedia oriented system transport standard ferrules. A 1×2 PMMA waveguide, which was designed to have an optimal angle of 15.8 deg at the beam splitting point, was fabricated using the injection molding method for mass production. The total volume of the fabricated 1×2 POF beam splitter is 48×18×12 mm3 with 1.2 m length input and output POF pigtails. From the measurement results, we experimentally confirm that the fabricated 1×2 POF beam splitter has excellent properties such as a beam splitting ratio of 50:50 ± 10 % and excess loss of less than 3.52 dB and it works well up to 250 Mbps for the automotive network.

A bridge between the single-photon and squeezed-vacuum states

The two modes of the Einstein-Podolsky-Rosen quadrature entangled state generated by parametric down-conversion interfere on a beam splitter of variable splitting ratio. Detection of a photon in one of the beam splitter output channels heralds preparation of a signal state in the other, which is characterized using homodyne tomography. By controlling the beam splitting ratio, the signal state can be chosen anywhere between the single-photon and squeezed state.

Analysis of experimental error sources in a linear-optics quantum gate

Possible error sources in an experimentally realized linear-optics controlled-Z gate (Okamoto et al 2005 Phys. Rev. Lett. 95 210506) are analyzed by considering the deviations of the beam splitting ratios from the ideal values (δRH, δRV), the polarization-dependent phase shift (birefringence) of the optical components (δϕ) and the mode mismatch of input photons (δξ). It is found that the error rate is linearly dependent on δRV and δξ, while the dependence on δRH and δϕ is approximately quadratic. As a practical result, the gate is much more sensitive to small errors in RV than in RH. Specifically, the reflectivity error for vertical polarization must be less than 0.1% to realize a gate with an error of less than 0.1%, whereas the reflectivity error for horizontal polarization can be up to 1%. It is also shown that the effects of different error sources are not independent of each other (linear error model). Under certain conditions, the deviation from the linear error model exceeds 10% of the total error. The method of analysis used illustrates the basic features of errors in general linear optics quantum gates and circuits, and can easily be adapted to any other device of this type.

Electrically Controlled Liquid Crystal Phase Grating for Terahertz Waves

This work demonstrates the feasibility of electrically controlled liquid-crystal-based phase grating for manipulating the terahertz (THz) waves. This device can be utilized as a THz beam splitter and the beam splitting ratio of the zeroth- to the first-order diffractions can be tuned from 10:1 to 1:1.

An efficient source of continuous variable polarization entanglement

We have experimentally demonstrated the efficient creation of highly entangled bipartite continuous variable polarization states. Exploiting an optimized scheme for the production of squeezing using the Kerr non-linearity of a glass fibre we generated polarization squeezed pulses with a mean classical excitation in . Polarization entanglement was generated by interfering two independent polarization squeezed fields on a symmetric beam splitter. The resultant beams exhibit strong quantum noise correlations in the dark polarization plane. To verify entanglement generation, we characterized the quantum correlations of the system for two different sets of conjugate Stokes parameters. The quantum correlations along the squeezed and the anti-squeezed Stokes parameters were observed to be −4.1±0.3 and −2.6±0.3 dB below the shot noise level, respectively. The degree of correlations was found to depend critically on the beam-splitting ratio of the entangling beam splitter. Carrying out measurements on a different set of conjugate Stokes parameters, correlations of −3.6±0.3 and −3.4±0.3 dB have been observed. This result is more robust against asymmetries in the entangling beam splitter, even in the presence of excess noise.

Transmission characteristics of copper mesh at 118.8 μm

An experimental investigation of the optical transmission characteristics of an electroformed copper wire mesh at an angle of 45° to incident radiation at 118.8 μm is reported. It is shown that the transmission coefficient is highly sensitive to the input beam polarization and the results obtained are in good agreement with those reported elsewhere. A comparison, however, with previously reported results for a mesh of the same type shows that microscopic differences in the physical dimensions of the mesh give rise to sizeable differences in the magnitude of the transmission coefficient, which is an important consideration in the design of multi-mesh beam-splitting systems when precise beam splitting ratios are required.

Optically tunable adiabatic beam splitter

We demonstrate that a twin-core coupler that is composed of nonlinear material with gain behaves like a tapered (linear) coupler and also has a beam-splitting ratio that is optically tunable. This conceptual approach reveals a new class of twin-core all-optical devices that exchange power adiabatically between the cores rather than by the more familiar method of resonance coupling or phase matching.

Spectral response measurements on polarisation splitting ratio of fused-taper single-mode fibre couplers

Using a Ge PIN photodiode cooled to 77 K (?196°C) with liquid nitrogen and the lock-in amplification technique, an automatic polarisation spectral response measurement system with a measuring dynamic range of about 36 dB has been developed. It has been confirmed experimentally that the spectral response of polarisation beam-splitting ratios of fused-taper fibre couplers depend on the incident polarisation angle

Variable-reflectance thin-film polarization-independent beam splitters for 06328- and 106-μm laser light

Truly polarization-independent beam splitters for 0.6328- and 10.6-microm (He-Ne and CO(2)) laser radiation are designed using single-layer-coated (Cleartran) ZnS and Ge prisms. These devices are found to be reasonably achromatic, their reflectance (beam-splitting ratio) can be varied over a wide range with little accompanying polarization error, and they are tolerent to small film-thickness and film refractive-index errors.

Integrated optical beam splitters formed in glass channel waveguides having variable weighting as determined by mask dimensions

Variable-weight beam splitters integrated into glass channel optical waveguides have been fabricated and successfully operated. Variable weighting is achieved by varying mask dimensions. Beam splitting is achieved by introducing notched reflectors of variable size into glass channel waveguides which are formed in shallow grooves having trapezoidal cross sections on silicon substrates. Preferential etching is used to fabricate these grooves and notches. A novel lift-off method incorporating a photoresist, glass, and aluminum sandwich structure is introduced to define glass channel waveguides having smooth edges within the grooves. The extent of the beam splitting notch as determined by scanning electron microscope observation is shown to correspond directly with measured beam splitting ratios for four different ratios. An insertion loss of 0.34 dB is measured for one of the samples.

High-Precision Angle Determination by Means of Radar in a Search Mode

One of the more difficult requirements to meet in the design of radars is that of accurate angular measurement. In tracking radars the azimuth and elevation of a target can be measured to a high degree of accuracy by a nulling method. Two of the most practical methods for obtaining angular accuracy in search radars are discussed in this paper. The first method is an interferometer technique employing either two receiving antennas for each dimension of angular measurement with two frequencies of transmission for the resolution of ambiguities, or three receiving antennas positioned relative to one another so that the equivalent effect is achieved with only one-frequency transmission. The second method is a combination amplitude comparison and interferometer technique in which the ambiguities are resolved by the amplitude comparison system. An analysis of each of these systems has been made using a statistical approach in which equations are developed relating the probability of error for a specified angular accuracy to SNR power in the receiver. Curves are presented which show this relationship for a 100 to 1 beam-splitting ratio.