Panda Polarization-maintaining Fiber Research Articles

TE/TM mode electro-optic conversion based on a titanium diffusion lithium niobate waveguide with a polarization-maintained fiber structure.

For the development of photonic integrated circuits and lithium niobate (L i N b O 3, LN) optical waveguide technology, the implementation and application of polarization devices based on LN are also becoming more widespread, where titanium (Ti)-diffused LN waveguides form the basis of many important electro-optic (EO) integrated optical devices. Moreover, utilizing polarization conversion has the potential to enhance both the effectiveness and capacity of optical transmission. Thus, we have presented an EO polarization mode converter packaging with PANDA polarization-maintaining optical fibers (PMFs) in the broadband wavelength range (1440-1620nm) to obtain the multiwavelength modulation, featuring the wavelength tunability. Additionally, the fabricated device is able to achieve transverse electric (TE) to transverse magnetic (TM) mode conversion efficiently with the applied voltage of ±, which provides high conversion efficiency. Importantly, our device also features a high-frequency response of about 600MHz with overall insertion loss below 5dB. The rapid development of LN-based polarization devices holds great promise for chip-integrated systems in the field of polarization telecommunication.

PANDA Fiber Sagnac Interferometer for Temperature Sensor Application

Fiber Sagnac loop mirror has great potential for use in various application such as multi-wavelength laser source, strain and temperature sensors. This paper demonstrates an optical fiber temperature sensor based on two lengths of PANDA polarization maintaining fibers (PMFs) in a fiber Sagnac interferometer. The temperature sensing is based on the change of spectral spacing of the generated optical comb with the temperature difference between two PMFs. The performance of the system was characterized numerically and experimentally by measuring the spectral spacing when raising the temperature of one of the PMFs. A high temperature sensitivity up to 0.36 nm/°C is obtained, with detuning range of 43 nm. This makes it a good candidate for various in-field sensing application.

Radiation-induced attenuation of hollow-core photonic bandgap fiber for space applications

Radiation-Induced Attenuation (RIA) is a crucial parameter for the applications of fiber optic gyroscopes in space environments. Under the irradiation of a 60Co source with a radiation rate of 10 rad/s and a total radiation dose of 138 krad, we make real-time measurements of RIA and evaluate the recovery process of homemade 19-cell HC-PBGF and commercial PPMF. Experimental results demonstrate that there is only a 0.45 dB/km loss increment for the RIA of homemade HC-PBGF at the wavelength of 1550 nm, which is only about 1/27 of that of the PPMF. After the radiation source is turned off, the loss of HC-PBGF returns to the initial level before radiation in the tenth hour, but the RIA of PPMF has only a 20% recovery on the seventh day. We first theoretically investigate the kinetics and phenomenological equation of RIA in the Hollow-Core Photonic Band-Gap Fiber (HC-PBGF) and commercial Panda Polarization Maintaining Fiber (PPMF) in the γ-rays environment. Theoretical results proved that the initial defect concentration and RIA increase rate of HC-PBGF are only 1/3 and 1/6 of that of the PPMF. This proves that HC-PBGF can significantly reduce the RIA and exhibits a strong capacity of irradiation resistance, which is of great significance to promote fiber optic gyroscopes for space applications.

Improved Thermal Stability of a Fiber Optic Gyroscope Using a Geometric Birefringence-Enhanced Polarization- Maintaining Fiber

In this paper, we propose and experimentally demonstrate an interferometric fiber optic gyroscope (IFOG) composed of an optimized elliptical-core Panda polarization-maintaining fiber (PMF) based on a comprehensive analysis of the design principle of PMFs for IFOGs. The improvement mechanism of the geometric birefringence on the performance of the Panda PMF was analyzed using the finite element model, and the optimized structural parameters were selected for fiber fabrication. The extinction ratio, polarization crosstalk, and assembled closed-loop IFOG output were tested and compared for fiber coils wound by different fiber structures under different temperature loads. An angle random walk performance of 0.001723 °/√h was achieved, which is a significant improvement over the traditional IFOG. The experimental results confirmed the proposed design basis that the elliptical-core Panda PMF with both higher birefringence and lower effective mode refractive index can improve the temperature stability of the IFOG.

Thermal Sensitivity of Birefringence in Polarization-Maintaining Hollow-Core Photonic Bandgap Fibers

Polarization-maintaining (PM) fiber is the core sensitive component of a fiber optic gyroscope (FOG); its birefringence temperature stability is crucial for maintaining accuracy. Here, we systematically investigated the structural thermal deformation and the resulting birefringence variation in typical PM hollow-core photonic bandgap fibers (HC-PBGFs) for FOG according to varying fiber structure parameters. To verify the application potential of PM HC-PBGFs in FOG, we compared the thermal sensitivity of birefringence (TSB) with that of the commonly used Panda PM fiber, which was tested to 5.07 × 10−5/100 °C. For rhombic-core fibers, the TSB was determined by the structure of the cladding and could be tuned as low as low as 10−7/100 °C, two orders of magnitude smaller than that of the panda PM fibers. For hexagonal-core fibers, the birefringence variation depended mainly on the drift of the surface modes (SMs) caused by the deformation of the core. A slight drift in SMs could cause a dramatic birefringence variation in hexagonal-core fiber, and the TSB could be as high as 10−4/100 °C, much higher than that of panda PM fiber. This study lays the foundation for the development of high birefringence temperature-stable HC-PBGFs and their applications in FOG.

An optical fiber sensor for the detections of liquid level and strain through cascading Sagnac interference and modal interference

An optical fiber sensor for the detections of strain and liquid level was experimentally investigated in this paper. This sensor was fabricated through cascading the Sagnac interference (SI) and multi-mode interference (MMI). A construction of single mode fiber-no core fiber-single mode fiber (SMF-NCF-SMF) was used to excite the MMI, while a section of 10.0 cm long Panda polarization maintaining fiber (PMF) was utilized to generate the polarization modes interference in the Sagnac loop. Two interference valleys corresponding to the MMI and SI appeared in the transmission spectrum and were utilized to detect the liquid level and strain, respectively. The measurement sensitivity of liquid level is higher than most of the reported sensors. This designed sensor could become a good candidate for the liquid level and strain detection owing to the simple structure, high sensitivity, and low hysteresis effect.

High extinction ratio and low backreflection polarization maintaining hollow-core to solid-core fiber interconnection.

We develop a hybrid cold/heat two-step splicing approach for low loss, low backreflection, and high polarization extinction ratio (PER) hollow-core to solid-core fiber interconnection. The employed hollow-core fiber (HCF) is our recently developed high-birefringence polarization-maintaining hollow-core fiber (PM-HCF) with a PER value of ∼30 dB, and the solid-core fiber (SCF) is a commercial Panda polarization-maintaining fiber (Panda fiber). Simultaneous low backreflection (<-35 dB), low insertion loss (IL) (∼0.7 dB), and high PER (∼27 dB) are achieved, representing the first high-performance PM-HCF/SCF interconnections, to the best of our knowledge. This greatly facilitates the applications of PM-HCF in widespread fields such as precise metrologies, gyroscopes, and ultrafast/high-power laser deliveries.

Experimental Study on Dual-Parameter Sensing Based on Cascaded Sagnac Interferometers With Two PANDA Fibers

A sensitivity-amplifying optical fiber sensor using cascaded Sagnac interferometers (CSIs) was designed and experimentally demonstrated for the dual-parameter measurement of strain and temperature. The proposed CSIs sensor consisted of two Sagnac interferometers (SIs) in which two identical PANDA polarization-maintaining fibers (PMFs) for just slightly different lengths were inserted. An envelope with a period of 123.6 nm, which was amplified more than 10 times than the single SI, was observed in the interference spectrum. Experimental results showed that the strain sensitivity increased from 32.91 pm&#x002F;&#x03BC;&#x03F5; for the single SI to 336 pm&#x002F;&#x03BC;&#x03F5; for the CSIs, while the temperature sensitivity increased from &#x2212;1.38 nm&#x002F;&#x00B0;C for the single SI to &#x2212;14.86 nm&#x002F;&#x00B0;C for the CSIs, correspondingly. We also found that the envelope of the CSIs shifted in opposite directions when the longer or shorter PMF was selected as the sensing arm. Higher sensitivity could be realized by selecting longer PMF as the sensing arm. Our proposed CSIs sensor possesses the merits of simple structure, high sensitivity, low cost, and low hysteresis effect, which make it a competitive candidate for strain and temperature monitoring.

Ultrasensitive fiber-optic temperature sensor based on cascaded Sagnac interferometers with a nematic liquid crystal film

We demonstrated an ultrasensitive fiber-optic temperature sensor based on cascaded Sagnac interferometers (CSIs). One of the Sagnac interferometers (SIs) consisted of a panda polarization-maintaining fiber (PMF) as the reference arm, while the other one contained two single-mode patch cables in a ferrule matching sleeve as the sensing arm, where a nematic liquid crystal (NLC) film was infiltrated into the micron-scale gap of the sleeve. In the sensing SI, the orientation of NLC film was induced by just rotating the two single-mode patch cables without any orientation agent, electric, or magnetic devices. Vernier effect was acquired by adjusting the thickness of NLC film. Experimental results revealed that the temperature sensitivity of the CSIs was up to 43.13 nm/°C, which was enhanced about 5 times compared to the single NLC SI. The designed optical fiber temperature sensor possessed the merits of compact structure, high stability, ultrahigh sensitivity, low hysteresis effect and high resolution, showing a promising application prospect in some scientific filed requiring accurate temperature measurement, such as biomolecules, medicine and other filed.

U-Shape Panda Polarization-Maintaining Microfiber Sensor Coated With Graphene Oxide for Relative Humidity Measurement

A new U-shape panda polarization-maintaining fiber (PPMF) based microfiber interferometer coated with graphene oxide (GO) film was proposed and experimentally demonstrated for relative humidity (RH) sensing. Experimental results show that the U-shape sensor has refractive index (RI) sensitivity of 1692.5 nm/RIU in the RI range of 1.33 when the diameter of the taper waist is 10.08 μm. The surface of the U-shape sensor was then modified chemically and coated with a thin layer of GO film (59.64 nm) for RH detection and the sensitivity is proportional to RH: as RH increases from 30% to 98%, the sensitivity increases from 0.111 to 0.361 nm/%RH and the response time is 0.28 s. In addition, the cross sensitivity to temperature, stability, reproducibility, and response/recovery time of the RH sensor were studied in detail. The proposed U-shape fiber RH sensor has advantage of high sensitivity, good reproducibility and fast response (0.28 s), which has potential application in areas requiring dynamic measurement of RH variations such as industrial product fabrication process control and breath state monitoring.

Group-Birefringence-Dispersion Measurements for Polarization-Maintaining Fibers Using a Kerr Phase-Interrogator

A method which utilizes a Kerr phase-interrogator to measure the group birefringence dispersion (GBD) of a polarization-maintaining fiber (PMF) is systematically studied in this paper. The differential group delay of two sinusoidally modulated optical signals (SMOSs) polarized along the principal axes of the PMF is measured by a Kerr phase-interrogator, which leads to the group birefringence of the PMF. As the laser wavelength of the SMOSs varies, the group birefringence as a function of the laser wavelength is obtained, and the GBD is calculated as the derivative of the group birefringence with respect to the laser wavelength. The proposed method is experimentally demonstrated by characterizations of a Panda PMF with high GBD and an elliptical core PMF with low GBD, and its performance is analyzed. The proposed method eliminates the impact of the laser coherent length and allows for characterizing the GBD of PMFs that are tens of kilometers long.

Strain and temperature discrimination using a fiber Bragg grating concatenated with PANDA polarization-maintaining fiber in a fiber loop mirror

A highly sensitive strain and temperature sensor which is formed by concatenating a fiber Bragg grating (FBG) with a section of PANDA polarization-maintaining fiber (PMF) in a fiber loop mirror (FLM) has been proposed and experimentally demonstrated to perform temperature and strain measurement. The sensing principle of high birefringence fiber loop mirror (HiBi-FLM) and FBG has been analyzed with formula derivation. Due to the different temperature and strain sensitivities of HiBi-FLM resonant dip and FBG resonant peak, the changes in applied strain and ambient temperature can be simultaneously determined by measuring the two resonance wavelengths shifts. High temperature sensitivity of −1.93 nm/℃ and strain sensitivity of 37.5 pm/με have been achieved respectively over the range of 20∼55 ℃ and 0∼789.6 με. The discrimination errors for temperature and strain are measured to be ± 0.5 ℃ and ± 18 με, respectively. The proposed sensor enjoys simple structure, good linearity, high sensitivity and low cost, and thus shows a good application prospects in various fiber-optic sensing applications.

Liquid-level sensing method based on differential pulse-width pair Brillouin optical time-domain analysis and a self-heated high attenuation fiber.

A liquid-level sensing method based on differential pulse-width pair Brillouin optical time-domain analysis (DPP-BOTDA) combining with a self-heated high attenuation fiber (HAF) is proposed, where the principle is to locate the temperature abruption position at the interface between liquid and air caused by their different thermal diffusion rates. A Panda polarization-maintaining fiber is used as the sensing optical fiber, which is tightly glued alongside a laser-powered HAF. Heated by a high-power laser, the temperature of the HAF can increase and exhibits approximately exponential attenuation with the light propagation direction, which induces a similar temperature distribution over the sensing fiber. By using a 5-cm spatial resolution DPP-BOTDA and a 1.4-W heating light, temperature distributions of the sensing fiber are measured for different water levels, and the results indicate that distributed liquid-level sensing with a range of 20 cm and a resolution of 1 cm is realized using our method.

Development of method for polarization alignment of PANDA polarization maintaining fiber

Abstract For making alignment technology of PANDA polarization maintaining fiber (PMF) more efficient, we propose a method based on Polarization Observation by the Lens-effect Tracing (POL) through complete theoretical derivation for the first time in this field of study. The mathematical model of imaging is created by conducting the ray equation of light transmitting in fiber and we can achieve polarization alignment by means of adjusting position of the brightest fringe on receiving screen. Some alignment errors outside the method itself are also analyzed to eliminate. Additionally, experiments were designed and carried out to measure the alignment accuracy and indicated that our method is valid for it can achieve the accuracy of polarization alignment

Highly Sensitive Directional Torsion Sensor Based on a Helical Panda Fiber Taper

A novel directional torsion sensor based on a helical taper is proposed and experimentally demonstrated. The helical taper was fabricated in panda polarization-maintaining fiber by electric-arc discharge of a fusion splicer and by rotating one end fiber clamp simultaneously. The optimal parameters of the taper are the waist diameter of $60.84~\mu \text{m}$ and the length of $700~\mu \text{m}$ . This torsion sensor has a sensitivity of −3.191 nm/(rad/m) in the twist rate ranges from 0 to 13.57 rad/m, which is relatively higher than the value so far reported. Then, the torsion sensor also has the ability to identify rotational direction. In addition, the helical taper is almost insensitive to temperature.

Research on temperature sensing characteristics with cascaded fiber Sagnac interferometer and fiber Fabry–Perot interferometer-based fiber laser

We have proposed and experimentally demonstrated a compact temperature sensor based on cascaded fiber Sagnac interferometer (FSI) and fiber Fabry–Perot interferometer (FFPI) with Vernier effect. The FSI is composed of a certain length of panda polarization-maintaining fiber and a 3-dB four-port coupler, whereas FFPI consists of two collimators and a wave plate. Both are used for temperature sensing, but where FSI is more sensitive to temperature than FFPI, the free spectral ranges of the two interferometers differ by 0.12 nm. The experimental results show that the temperature sensitivity is increased from −1.7 nm / ° C (single FSI) and 0.008 nm/°C (single FPI) to 10.28 nm/°C (cascade configuration), which is basically consistent with the theoretical analysis (10.82 nm/°C).

Determination of total rotation of polarization axes in polarization-maintaining fibers

A simple method is proposed to measure the total rotation of polarization axis caused by both internal and external factors during the fabrication process in polarization-maintaining fibers (PMFs). The method is suitable for any kind of PMF, and avoids the additional clamping-induced rotation of fiber with assistance of gravity. Based on this method, a polarization-maintaining photonic crystal fiber (PM-PCF) and a conventional panda PMF used in fiber-optic gyroscope (FOG) are tested. The experimental results provide foundation for the analysis of fiber quality and magnetic-induced bias error in a FOG. © 2018 The Author(s).

Fiber optic birefringence enhanced accelerometer based on polarized modal interferometer

An inline fiber optic birefringence enhanced accelerometer (FOBEA) which applies one polarizer and a ten-meter high birefringence fiber wrapped on a transducer cylinder is proposed. Birefringence of polarized modes in panda polarization maintaining fiber (PMF) is enhanced by fiber coating and cylinders of different parameters. Accelerometers with copper cylinder (FOBEA-1) and polyurethane cylinder (FOBEA-2) are fabricated, the tested average sensitivities are 1.06rad/g (20-3800 Hz) and 16.97 rad/g (20-2000 Hz). The experimental results show the birefringence gain of FOBEA-1 is in good consistent with theoretical calculation of 1.07 and an additional birefringence gain of FOBEA-2 is 5.52 because the polyurethane cylinder works as fiber coating with the thickness of 1.21 mm. Temperature crosstalk is also investigated.

Vernier effect of fiber interferometer based on cascaded PANDA polarization maintaining fiber

This Letter shows the Vernier effect based on two segments of PANDA polarization maintaining fiber (PMF), whose lengths are 28 and 23 cm, respectively. The two PMFs are spliced together, and the angle between the fast axes is set to 45°. This cascaded PMF is inserted in a Sagnac loop to form an interferometer that can generate the Vernier effect. The spectrum consists of finesse fringe and envelope and realizes simultaneous measurement of strain and temperature. The envelope can provide strain and temperature sensitivities of 58.0 pm/μe and −1.05 nm/°C. The finesse fringe provides sensitivities of 5.9 pm/μe and −1.36 nm/°C.

A High-Birefringence Microfiber Sagnac-Interferometer Biosensor Based on the Vernier Effect.

We propose a high-sensitive Sagnac-interferometer biosensor based on theVernier effect (VE) with a high-birefringence microfiber. The sensitivity enhancement is achieved by utilizing two cascaded Sagnac interferometers. One of the two interference loops consists of a panda polarization-maintaining fiber as a filter, whilst the other is comprised of high-birefringent microfiber coated Graphene oxide (GO) as a sensing channel. We theoretically analyzed the sensitivity of the sensor and verified it with experiments. The results of the simulation show that the refractive index sensitivity is more than five times that of the fiber sensor based on a single Sagnac loop. The sensitivity of the refractive index in the experiments can reach 2429 nm/refractive index unit (RIU), which is basically in accordance with the simulation. We also use electrostatic adsorption to coat GO on the surface of the sensing channel. GO is employed to adsorb bovine serum albumin (BSA) molecules to achieve the desired detection results, which has good biocompatibility and large specific surface area. The sensitivity to detect BSA can reach 9.097 nm/(mg×mL−1).