Side-polished Photonic Crystal Fiber Research Articles

Dual-channel photonic crystal fiber dual-parameter sensor exploiting surface plasmon resonance

A surface plasmon resonance (SPR) based sensor using a negative curvature circular side-polished photonic crystal fiber was proposed. The sensor’s sensitivity was analyzed using the finite element method. The impact of structural parameters was investigated. The sensor exhibits an average wavelength sensitivity (WS) of 7846 nm/RIU in the refractive index range of 1.370–1.396 and 2350 nm/RIU in the range of 1.330–1.370, with maximum WS of 46000 nm/RIU. For refractive index and magnetic field dual-parameter sensing, the simultaneously obtained magnetic field sensitivity is 0.84 nm/mT. The proposed SPR sensor demonstrates remarkable sensitivity, making it suitable for refractive index and magnetic field sensing applications.

Design and Analysis of Surface Plasmon Resonance Sensor with Open-Loop Side-Polished Photonic Crystal Fiber

Design and Analysis of Surface Plasmon Resonance Sensor with Open-Loop Side-Polished Photonic Crystal Fiber

A wide measurement range plasmonic refractive index sensor based on side-polished photonic crystal fiber

A wide measurement range plasmonic refractive index (RI) sensor based on side-polished photonic crystal fiber (PCF) was proposed and studied in this paper. A composite film containing an Au layer and a TiO2 layer was coated on the polished surface of PCF to excite and modulate the surface plasmon resonance (SPR) effect. The sensing characteristics were analyzed using the finite element method (FEM). Numerical results showed that the sensing performances were significantly improved through introducing the unique optoelectronic material of TiO2 film. The designed RI sensor showed an ultra-wide measurement range of 1.20–1.38 with a highest sensitivity of 14600 nm RIU−1. The best resolution (R) and figure of merit (FOM) reached 6.85 × 10−6 RIU and 224.62 RIU−1, respectively. The designed side-polished PCF which is coated with an optimized TiO2/Au composite membranes has a promising performance in the field of RI sensing requiring high sensitivity and wide range monitoring.

Side-polished photonic crystal fiber sensor with ultra-high figure of merit based on Bloch-like surface wave resonance

A Bloch surface wave (BSW) resonance configuration is introduced for biosensing with an ultra-high figure of merit (FOM). The BSW excitation is realized through the evanescent field of the core-guided fundamental mode of a side-polished photonic crystal fiber (PCF). By taking advantage of the air hole periodic microstructure of the PCF cladding, the BSW platform can be achieved with only a single high refractive index dielectric layer on its flat surface. The dielectric layer deposited on the polished surface of the PCF modifies the local effective refractive index, allowing direct manipulation of the BSWs, whereby the resonance wavelength of the surface wave can be adjusted by choosing the material and thickness of this layer. Here, we numerically investigate Bloch-like surface wave (BLSW) resonance conditions around telecom wavelengths for silicon, titanium dioxide, copper monoxide, and aluminum oxide termination layers. The BLSW excitation platform materials have low loss, which results in higher surface field enhancements and narrower resonances, which are advantageous properties for the sensors. The obtained results open new avenues for the application of optical surface waves in biosensing with high FOM. Furthermore, these results show a much higher figure of merit (FOM) than traditional approaches, allowing for increased sensitivity and accuracy.

Bilaterally Polished Photonic Crystal Fiber Magnetic Field Sensor Based on Lossy Mode Resonance

A kind of magnetic field sensor is proposed, which is based on symmetrically side-polished photonic crystal fiber (PCF) with regular hexagonal air holes. Magnetic fluid (MF) is used as the magnetic field-sensitive material. The polished surfaces are coated with an indium tin oxide (ITO) film to generate lossy mode resonance (LMR) for magnetic field sensing. The obtained magnetic field sensitivity is 466.81 pm/Oe, which can be further adjusted by changing the thickness of the ITO film. The comprehensive sensing performance is evaluated by defining the figure of merit (FOM). The proposed structure is simple and has the capability of mass production, which has great development space in the future.

Design of surface plasmon resonance based both side polished photonic crystal fiber for highly efficient refractive index sensor

In this paper, both sides flat photonic crystal fiber-based surface plasmon resonance (PCF-SPR) sensor has been proposed. In this external sensing mechanism based sensor, we have used gold as plasmonic material with an adhesive TiO2 layer over it, enhancing the interaction between analyte channel and gold metal. Using the wavelength interrogation and amplitude interrogation method, the maximum wavelength and amplitude sensitivities are obtained 22,800 nm/RIU and 947 RIU−1, respectively, for analyte range 1.30–1.40 with a maximum wavelength resolution of 4.38 × 10−6. With Full-width half maxima (FWHM) around 45 nm, the sensor provides a high figure of merit (FOM) 507 RIU−1. The proposed sensor can be fabricated from newly available technologies such as the sol-gel method, stack and draw method for several practical applications in the bio-medical field, bio-chemical field to provide higher and accurate sensing results. The presented sensor has also played a vital role in cancer cell detection with higher sensing performance.

High sensitivity plasmonic temperature sensor based on a side-polished photonic crystal fiber

A high sensitivity plasmonic temperature sensor based on a side-polished photonic crystal fiber is proposed in this work. In order to achieve high sensitivity and high stability, the gold layer is coated on the side-polished photonic crystal fiber to support surface plasmon resonance. The mixture of ethanol and chloroform is used as the thermosensitive liquid. The performances of the proposed temperature sensor were investigated by the finite element method (FEM). Simulation results indicate that the sensitivity of the temperature sensor is as high as 7.82 nm/°C. It has good linearity (R 2 = 0.99803), the resolution of 1.1 × 10−3 °C, and the amplitude sensitivity of 0.1008 °C−1. In addition, the sizes of the small air hole and polishing depth have little influence on the sensitivity. Therefore, the proposed sensor shows a high structure tolerance. The excellent performance and high structure tolerance of the sensor make it an appropriate choice for temperature measurement.

Temperature effects on surface plasmon resonance sensor based on side-polished D-shaped photonic crystal fiber

A comprehensive temperature Drude theoretical mode has been established to study the temperature effects on the side-polished photonic crystal fiber (PCF) surface plasmon resonance (SPR) sensor. In the theoretical model, the temperature dependence coefficients of fiber material refractive index (RI), sensing film thickness and metal-dielectric function have been considered. The finite element method (FEM) is used to study the influence of side-polished depth, metal thickness, air hole size, and lattice constant on sensing performance with findings as following: (1) the dependence of the resonance wavelength on temperature is almost unaffected by duty ratio or lattice pitch of PCF; (2) the peak loss of the PCF SPR sensor with small lattice pitch (or increased duty ratio) is more sensitive to temperature variation; (3) for the sensor working in intensity interrogation mode, linear relationships can be found between the peak loss versus the RI and temperature. Moreover, we fabricate a side-polished D-shaped PCF SPR sensor by a wheel polishing setup, and the experimental results display a good agreement with the theoretical investigations. This study offers a detailed way to analyze the temperature effects on the sensor, and may lead to the better design and the data-progress improvement for D-shaped PCF SPR sensor.

Highly sensitive dual-core symmetrical side-polished modified D-shaped SPR based PCF refractive index sensor with deeply etched micro openings

A novel dual side-polished photonic crystal fiber (DSP-PCF) refractive index (RI) sensor is proposed for the RI detection range of 1.30−1.35. An active plasmonic metal gold (Au) is deposited on a polished flat fiber surface to generate plasmons so that it can detect the change in RIs of its surrounding medium. A thin titanium dioxide (TiO2) layer is coated to assist the adhesion of Au layer with silica-based fiber. To enhance the sensitivity, silicon nitride (Si3N4) is deposited on the top of Au to make it as a dielectric sensing layer. Simulation outcomes demonstrate that the maximum wavelength sensitivity (WS), amplitude sensitivity (AS) and RI resolution reach the highest value of 35,000 nmRIU−1, 350 RIU−1 and 4.347×10-6RIU, respectively, for DSP-PCF. Additionally, the obtained WS for DSP-PCF is far better than the recently reported PCF sensors in the above mentioned RI detection range to the best of our knowledge. With these significant outcomes over the wide analyte RI range, the proposed sensor opens new possible study windows in the field of organic chemicals and biological sensing.

Sensing properties of symmetrical side-polished photonic crystal fiber based on surface plasmon resonance

A kind of symmetric side-polished photonic crystal fiber is designed for sensing application based on the surface plasmon resonance technology. The finite element method is used to study the influence of structural parameters on the sensing performance. The average wavelength sensitivity (WS) is 2380 nm/RIU for the refractive index ranging from 1.340 to 1.380, and the average WS is 6260 nm/RIU when the refractive index changes from 1.380 to 1.406. The maximum WS at refractive index of 1.406 is 9333 nm/RIU. Furthermore, the polydimethylsiloxane and magnetic fluid are used as the temperature and magnetic field sensitive materials, respectively. Simultaneous measurement of magnetic field and temperature is realized. The magnetic field and temperature sensitivities are 0.60 nm/mT and -4.09 nm/°C, respectively. The designed scheme solves the problem of temperature cross-sensitivity of the magnetic field sensor.

SPR based magnetic-field sensing in microchannelled PCF: a numerical approach

We propose a surface plasmon resonance (SPR) based magnetic field sensor using a microchannel incorporated side-polished photonic crystal fiber (PCF). A side polished PCF, when exposed to a high energy Gaussian pulse in the transverse direction, engraves a microchannel on the flat surface. The inner surface of the microchannel is assumed to be coated with indium tin oxide (ITO) and the microchannel is to be filled with magnetic fluid (MF). The refractive index (RI) of MF could be varied via application of magnetic field. The principle of the device is based on the excitation of surface plasmon wave at the ITO-MF interface and the corresponding shift in SPR peak due to the change in RI of MF. The presence of ITO helps in excitation of surface plasmon in the near infrared wavelength band. Through numerical analysis, we estimate the magnetic field sensitivity of the proposed device to be 564 pm Oe−1 (5.64 nm/mT) for weaker magnetic field with a maximum resolution of 0.177 Oe. Further, the proposed sensor can be utilized for intensity based magnetic field sensing where its sensitivity is of the order of 0.005/Oe.

Ultrahigh-sensitivity refractive-index sensor based on gold-coated side-polished photonic crystal fiber

The coupling characteristics of a gold-coated side-polished photonic crystal fiber based on surface plasmon resonance are simulated. The resonant points undergo a blue-shift unexpectedly when the refractive indices of the analytes range from 1.32 to 1.50, and a negative sensitivity is observed in the sensing scheme. The wavelength and amplitude are investigated to characterize the device. The highest negative wavelength sensitivity is −40,400 nm/RIU with a resolution of 2.48 × 10−6 RIU, and the corresponding amplitude sensitivity is as high as −1,246.47 RIU−1 with a resolution of 8.02 × 10−6 RIU. The sensor shows excellent performance that is comparable to previous reports.

Surface plasmon resonance biosensor based on gold-coated side-polished hexagonal structure photonic crystal fiber.

The refractive index sensing characteristics of the side-polished photonic crystal fiber (PCF) surface plasmon resonance (SPR) sensor are detailed investigated in this paper. We used the finite element method (FEM) to study the influences of the side-polished depth, air hole size, lattice constant, and the refractive index (RI) of the PCF material on sensing performance. The simulation results show that the side-polished depth, air hole size, lattice pitch have significant influence on the coupling strength between core mode and surface plasmon polaritons (SPPs), but have little influence on sensitivity; the coupling strength and sensitivity will significant increase with the decrease of RI of the PCF material. The sensitivity of the D-shaped PCF sensor is obtained to be as high as 21700 nm/RIU in the refractive index environment of 1.33-1.34, when the RI of the PCF material is controlled at 1.36. It revealed a new method of making ultra-high sensitivity SPR fiber sensor. Then we experimental demonstrated a SPR refractive sensor based on the side-polished single mode PCF and investigated the sensing performance. The experimental results of the plasmon resonance wavelength sensitivity agree well with the theoretical results. The presented gold-coated D-shaped PCF SPR sensor could be used as a simple, cost-effective, high sensitivity device in bio-chemical detection.

Optimization of polishing parameters for optical coupler based on side-polished photonic crystal fiber

The rapid development in areas such as fiber-optic communication, fiber lasers, and high power transmission has generated an increasing demand for photonic crystal fiber (PCF). However, there is no well-proven approach for PCF coupler fabrication because most approaches proposed introduce defects that are non-negligible in practice. Previously, we have made an attempt by applying side-adhering technique to PCF coupler fabrication. This paper presents our recent effort in establishing a model of side-polished PCF (SPPCF) coupler and tuning various fabrication parameters in search for its desirable characteristics. It is found that the optimal coupling effect is achieved when the residual radius is set 5.7 μm and the polishing angle is set 0°. The optimizations presented in this paper may serve as a foundation for further research and development of SPPCF coupler.

Research on Coupler of Single Mode Fiber with Photonic Crystal Fiber

A coupler of single mode fiber with photonic crystal fiber with a coupling ratio of 0 to 90% was fabricated with a new method called Auto-deposition Fused Side-adhere. A model for coupler of side-polished single mode fiber with side-polished photonic crystal fiber was established which proves it feasible to make such a coupler practically. In the range of 1520~1620nm, the Wavelength Dependent Loss (WDL) of the through port was 0.3dB and of the coupled port was 5dB. The Polarization Dependent Loss of through port was 0.25dB and 0.31dB at 1310nm and 1550nm, and the WDL of coupled port was 1.46dB and 1.75dB. When temperature changed from 10°C to 80°C and humidity changed from 10% to 70%, coupling ratio changed about 7% to 16%. It can be concluded that a steady coupler of single mode fiber with photonic crystal fiber can be made with the Auto-deposition Fused Side-adhere Coupling method, which can give a reference method and lay an experimental foundation for the fabrication of photonic crystal fiber coupler.

侧边抛磨光子晶体光纤传输特性理论分析

侧边抛磨光子晶体光纤传输特性理论分析

Tunable photonic crystal fiber coupler based on a side-polishing technique.

A tunable photonic crystal fiber (PCF) coupler, which couples part of the optical power in one PCF with that in another PCF, has been made by side polishing. We fabricated the PCF coupler by mating two side-polished PCFs. We achieved evanescent field coupling between the core modes of the two PCFs by using side polishing to bring the cores close to each other. By adjusting the mating angle between the two side-polished PCFs we obtained as much as 90% tunability in the coupling ratio. The spectrum of the coupling ratio was almost flat, with small ripples, over a 400-nm wavelength range.