Agus Muhamad Hatta

Use of a Bent Single SMS Fiber Structure for Simultaneous Measurement of Displacement and Temperature Sensing

We have proposed the use of a single bent singlemode -multimode-singlemode (SMS) fiber structure to measure both displacement and temperature simultaneously and independently. Our experimental results show that this sensor has a sensitivity of 5.89 pm/μm for displacement and 11.6 pm/°C for temperature.

Experimental demonstration of a simple displacement sensor based on a bent single-mode–multimode–single-mode fiber structure

A simple displacement sensor based on a bent single-mode–multimode–single-mode (SMS) fiber structure is proposed and experimentally investigated. The sensor offers a wider displacement range, not limited by the risk of fiber breakage, as well as a three-fold increase in displacement sensitivity by comparison with a straight SMS structure sensor. This sensor can be interrogated by either an optical spectral analyzer (OSA) or a ratiometric interrogation system: (1) if interrogated by an OSA assuming a resolution of 1 pm, it has a sensitivity of 28.2 nm for a displacement measurement range from 0 to 280 µm; (2) if interrogated by a ratiometric interrogation system, it has worst and best case resolutions of 556 and 38 nm, respectively, for a displacement measurement range from 0 to 520 µm.

Strain sensor based on a pair of single-mode- multimode-single-mode fiber structures in a ratiometric power measurement scheme

The strain and temperature dependencies of a step-index single-mode-multimode-single-mode (SMS) fiber structure are investigated numerically and experimentally. For intensity-based strain measurement using a single SMS fiber structure, at a selected wavelength, it is found that there is a high strain dependence, but also a temperature dependence that will induce strain measurement error. To minimize the temperature-induced strain measurement error, two SMS fiber structures are proposed and demonstrated in a ratiometric power measurement scheme; one SMS structure acts as the strain sensor, and the other SMS structure acts as the temperature monitor. The extracted temperature information is used to determine a strain value based on a suitable calibration of strain responses with temperature variations. It is demonstrated that for strain measurement from 0 to 1000 microepsilon within the temperature range from 10 degrees C to 40 degrees C, the proposed configuration can provide a strain and temperature resolution of 0.34 microepsilon and 0.14 degrees C, respectively, with a temperature-induced strain measurement error as low as 0.39 microepsilon.

Misalignment Limits for a Singlemode–Multimode–Singlemode Fiber-Based Edge Filter

Misalignment effects on the spectral characteristics of edge filters based on singlemode-multimode-singlemode (SMS) fibre structures are investigated numerically and experimentally. A modal propagation analysis is used with a set of guided modes calculated using the finite-difference method to determine the transmission loss of the SMS-based edge filters. A limit for the tolerable misalignment of the SMS fiber-based edge filter is proposed, beyond which the spectral performance of the SMS structure degrades unacceptably. The numerical results are verified experimentally with good agreement.

A design method for a ratiometric wavelength monitor using a pair of directional couplers acting as edge filters

An integrated ratiometric wavelength monitor is proposed and designed, which consists of a Y-branch and two directional couplers acting as edge filters with opposite spectral responses. With a local supermodes solution, the optimal separation distance between two waveguides and the interaction length of the directional coupler are obtained to meet the desired spectral response with significantly less computation time by comparison to a parameter-space scanning method. The wavelength discrimination ability of the designed ratiometric structure is demonstrated numerically.

Duelist Algorithm: An Algorithm Inspired by How Duelist Improve Their Capabilities in a Duel

This paper proposes an optimization algorithm based on human fight and learn from each duelist. The proposed algorithm starts with an initial set of duelists. The duel is to determine the winner and loser. The loser learns from the winner, while the winner try their new skill or technique that may improve their fighting capabilities. A few duelists with highest fighting capabilities are called as champion. The champion train a new duelist such as their capabilities. The new duelist will join the tournament as a representative of each champion. All duelist are re-evaluated, and the duelists with worst fighting capabilities is eliminated to maintain the amount of duelists. Several benchmark functions is used in this work. The results shows that Duelist Algorithm outperform other algorithms in several functions.

A simple integrated ratiometric wavelength monitor based on multimode interference structure

Wavelength measurement or monitoring can be implemented using a ratiometric power measurement technique. A ratiometric wavelength monitor normally consists of a Y-branch splitter with two arms: an edge filter arm with a well defined spectral response and a reference arm or alternatively, two edge filters arms with opposite slope spectral responses. In this paper, a simple configuration for an integrated ratiometric wavelength monitor based on a single multimode interference structure is proposed. By optimizing the length of the MMI and the two output port positions, opposite spectral responses for the two output ports can be achieved. The designed structure demonstrates a spectral response suitable for wavelength measurement with potentially a 10 pm resolution over a 100 nm wavelength range.

A Ratiometric Wavelength Measurement Based on a Silicon-on-Insulator Directional Coupler Integrated Device

A ratiometric wavelength measurement based on a Silicon-on-Insulator (SOI) integrated device is proposed and designed, which consists of directional couplers acting as two edge filters with opposite spectral responses. The optimal separation distance between two parallel silicon waveguides and the interaction length of the directional coupler are designed to meet the desired spectral response by using local supermodes. The wavelength discrimination ability of the designed ratiometric structure is demonstrated by a beam propagation method numerically and then is verified experimentally. The experimental results have shown a general agreement with the theoretical models. The ratiometric wavelength system demonstrates a resolution of better than 50 pm at a wavelength around 1550 nm with ease of assembly and calibration.

Simultaneous measurement of displacement and temperature with a single singlemode-multimode-singlemode (SMS) fiber structure

We report an experimental study of a SMS fiber sensor for simultaneously measuring both displacement and temperature. By measuring both central wavelength spectral shifts and peak power variations, displacement and temperature can be independently determined with a demonstrated sensitivity to displacement of 0.62 μm and a temperature sensitivity of 1 °C by using a typical OSA which has a wavelength resolution of 10 pm and power measurement resolution of 0.01 dB.

Accurate theoretical prediction for single-mode fiber macrobending loss and bending induced polarization dependent loss

For an all-fiber edge filter used in a rapid wavelength measurement system for optical sensing, a low polarization dependent loss (PDL) is required to ensure high measurement accuracy. The calculation of the bend loss for the TE and TM modes based on scalar approximations results in a discrepancy between the calculated PDLs and measured results. Here a full vectorial finite difference beam propagation method (FV FD-BPM) is used to compute the complex propagation constant and the field distributions of the TE and TM modes in the bending fiber, allowing the accurate calculation of the PDL of bending fiber.