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In this letter, we proposed a new method for a variable optical attenuator (VOA) through controlling a mechanical misalignment between 2 single mode fibers using a piezoelectric sheet. A piezoelectric sheet with 3 electrodes is adopted in our proposed structure. We can change amount of the bend of the PZT sheet by controlling the applied voltage on the inner electrode of the PZT sheet, which causes the optical loss to be dependent on the applied voltage. The numerical analysis about the optical loss related to the various mechanical offsets is also investigated. From our experimental results, the dynamic range of the proposed structure is about from 0 to 56 dB when the applied voltage range is from 0 to 22V DC. In our previous work using the piezoelectric tube, the dynamic range is about from 0 to 25dB when it is from 0 to 600V DC. The required voltage to get the same attenuation is dramatically reduced. It can make it more practical in the optical communication field.

This paper presents a sol-gel based 1×2 power splitter for an optical communication based on the plastic optical fiber. To find out optimum parameters of a power splitter, mode propagation along the splitter was theoretically analyzed using BPM (Beam Propagation Method) and the results show that the distance between two arms at the output port of a splitter should be kept below 100μm in order to increase the output power. The planar lightwave circuit device was fabricated by a nano imprint lithography process followed by a spin coating process. The core size and the length of a power splitter were 230 μm×230 μm and 2 cm, respectively. The measured surface roughness of core/cladding using the AFM (Atomic Force Microscope) was under 100nm. The characteristics of a fabricated power splitter were conducted using an 850nm VCSEL (Vertical Cavity Surface Emission Laser) source and 50:50 power splitting performance was obtained.

This study focuses on the design and analysis of a Rotor type magneto-rheological fluid (MR Fluid) brake and clutch. The brake's braking torque and the clutch's torque output can be easily controlled by adjusting the MR fluid and the configuration of Rotor. Electromagnetic finite element analysis(FEA) is performed, using FEMLAB software of the COMSOL Group, to find out the optimization conditions for the design of the Rotor type MR Fluid clutch and brake. In this paper, the design method of the Rotor type MR Fluid brake and clutch is investigated theoretically. The equation of the torque transmitted by the MR fluid within the Rotor type brake and clutch is derived to provide the theoretical foundation in the rotor design of the brake and clutch. The output torque values are recorded for different input velocities and applied magnetic fields, and the experimental results are compared with the theoretical results. Theoretical and experimental analyses have illustrated that this Rotor type MR fluid brake and clutch can transfer high controllable torques with a very fast time response. It was demonstrated that the Rotor type MR fluid clutch and brake have a strong capability of transmitting and isolating the high torque.

In this letter, we proposed a simple and cost-effective variable optical attenuator (VOA) through controlling a mechanical misalignment between 2 single mode fibers. A piezoelectric ceramic tube having 4 electrodes on the surface is the key component in our proposed structure. We can change the deflection of the tube by controlling the applied voltage on the electrodes of the tube, which causes the optical loss to be dependent on the applied voltage. The fact that the piezoelectric ceramic tube can be easily fabricated by using the electro-phoretic deposition processing makes our structure more attractive for mass production. The tube-fabrication processing is out of the range in this paper. So, the detail technical approach of the tube fabrication is excluded intentionally. The numerical analysis about the optical loss related to the various mechanical offsets is also investigated. From our experimental results, the dynamic range of the proposed structure is about from 0 to 25 dB when the applied voltage range is from 0 to 600 V DC. Our proposed structure can be a good candidate for a simple and cost-effective variable optical attenuator in optical communication system field.

In this letter, we propose the new first light search algorithm using 2 tilting stages in optical fiber component assembly process. The proposed algorithm is theoretically and experimentally investigated. The experimental results for 4 different initial light spot conditions show that the theoretical approach and the experiments of our algorithm are exactly matched and that our proposed algorithm can be a new candidate for the first light search algorithm in the fiber-optic component assembly industrial field.