[Clinical application of retrosigmoid approach for BONEBRIDGE implantation after auricle reconstruction using expanded postauricular flap].

Objective: To explore the safety and reliability of retrosigmoid approach BONEBRIDGE implantation in patients with auricle reconstruction using skin expansion flap. Methods: A retrospective analysis was conducted on 43 congenital aural atresia cases (43 ears) who underwent BONEBRIDGE implantation from September 2019 to January 2023 in Beijing Tongren Hospital. 30 males and 13 females were included in this work. The implantation age was 9-36 years old (median age=10 y/o). All cases underwent auricle reconstruction surgery using the posterior ear flap expansion method, with 36 cases using the single expanded postauricular flap method and 7 cases using two-flap method. BONEBRIDGE implant surgery was performed during the third stage of auricle reconstruction or after all stages. The hearing improvements were evaluated by comparing the changes in pure tone hearing threshold and speech recognition rate of patients before and after BONEBRIDGE implantation. Routine follow-up was conducted to observe the hearing results and complications. SPSS 14.0 software was applied for data statistical analysis. Results: All 43 patients healed well and had no surgical complications when discharge. The average bone conduction hearing threshold after surgery was (8.2±6.6) dBHL, and there was no statistically significant difference compared to the preoperative [(8.1±5.7) dBHL] (P=0.95). After surgery, the threshold of hearing assistance with power on was significantly lower than that without hearing assistance [(32.8±4.6) dBHL vs (60.5±5.5) dBHL], and the difference was statistically significant (P<0.001). The speech recognition rate of monosyllable words, disyllabic words and short sentences in quiet environment increased to 72%, 84%, and 98% respectively. The differences were statistically significant (P<0.001). The speech recognition rate of monosyllabic words, disyllabic words, and short sentences in noise environment was significantly increased by 70%, 80%, and 92% respectively (P<0.001). After a follow-up of 4 to 47 months (median=24 months), the hearing results were stable and the aesthetic outcomes were satisfying. One patient had delayed hematoma around coil of the implant. After aspiration and compressed dressing for one week, hematoma was not recurrent. Conclusion: For patients after auricle reconstruction using expanded postauricular flap, the preference of retrosigmoid approach is a good choice in terms of safety and reliability of operation, as well as aesthetic appearance.

[Comparison the characteristics of serum adrenocortical hormone profile in patients with adrenal cortical carcinoma and adrenal coritcal adenoma].

Objective: To compare the characteristics of serum adrenocortical hormone profiles detected by liquid chromatography tandem mass spectrometry in patients with adrenal cortical carcinoma and adrenal adenoma. Methods: A total of 23 patients with adrenal cortical carcinoma and 119 patients with adrenal cortical adenoma/hyperplasia who visited the Department of Endocrinology and/or the Department of Urology of Peking University First Hospital from January 2018 to June 2022 were analyzed retrospectively. The imaging characteristics and serum adrenal cortical hormone profiles detected by liquid chromatography tandem mass spectrometry were analyzed retrospectively. The independent related factors of adrenal cortical carcinoma were screened by univariate analysis and multivariate logistic regression analysis. Results: The age of patients with adrenal cortical carcinoma was 46 (35, 57) years, and 15 (65.2%) were female; The age of adrenal cortical adenoma patients was 49 (40, 58) years old, and 80 (67.2%) were female. There was no significant difference in age and gender between the two groups (all P values>0.05). The maximum tumor diameter M (Q1, Q3) of patients with adrenocortical carcinoma was 7.05 (5.45, 9.78) cm, which was larger than that of patients with adrenocortical adenoma [2.1 (1.6, 3.0) cm] (P<0.001). Compared with patients with adrenal adenoma, the androstenedione (AD) of patients with adrenal cortical carcinoma [4.056 9 (1.619 5, 7.907 9) nmol/L vs 1.517 5 (0.935 1, 2.582 1) nmol/L (P<0.001)] was significantly increased; 11-ketotestosterone/11-ketoandrostenedione [0.034 3 (0.020 6, 0.079 2) vs 0.041 0 (0.028 6, 0.061 5) (P=0.089)] and 11-ketoandrostenedione/11-hydroxyandrostenedione [0.013 0 (0.006 4, 0.086 7) vs 0.063 0 (0.018 2, 0.162 5) (P=0.042)] were significantly decreased. Multivariate analysis found that AD, the largest diameter of the tumor, 11-ketotestosterone/11-ketoandrostenedione and 11-ketoandrostenedione/11-hydroxyandrostenedi-one were related factors for adrenal cortical carcinoma, with OR values (95%CI) of 1.841 (1.093-3.100), 5.130 (2.332-11.285), 0.381 (0.167-0.867) and 0.000 (0.000-0.014), respectively, all P values <0.05. Conclusions: The larger diameter of adrenal cortical tumor and the higher the level of androstenedione are independent risk factors for adrenal cortical carcinoma. The reduction conversion of 11-hydroxyandrostenedione to 11-ketoandrostenedione and 11-ketoandrostenedione to 11-ketotestosterone were independently associated with adrenal cortical carcinoma.

Whispering gallery mode microsphere resonator based on cylindrical air cavity coupling.

In this Letter, an optical fiber whispering gallery mode microsphere resonator based on cylindrical air cavity coupling is proposed and demonstrated. The cylindrical air cavity is vertical to the axis of a single-mode fiber and in touch with the fiber core, fabricated by using femtosecond laser micromachining together with hydrofluoric acid etching. A microsphere is inserted into the cylindrical air cavity and in tangential contact with the inner cavity wall, which is in touch with or inside the fiber core. The light traveling in the fiber core is coupled into the microsphere via an evanescent wave when the light path is tangential to the contacting point of the microsphere and the inner cavity wall, resulting in whispering gallery mode resonance when the phase-matching condition is satisfied. Such a device is highly integrated, robust in structure, low in cost, stable in operation, and has a good quality factor (Q) of 1.44 × 104.

All-fiber saturable absorber based on slightly tapered graded index multimode fiber for conventional and bound soliton generation.

A slightly tapered graded index multimode fiber (GIMF) is demonstrated as the saturable absorber (SA) for a conventional soliton and tightly bound soliton generation. The SA device is simply a GIMF spliced with single-mode fiber (SMF) at its two ends. The waist diameter of the slightly tapered fiber is ∼23.8µm, located at one of the splicing points of SMF and GIMF. The mode-locked output of conventional solitons and tightly bound solitons can be obtained in a ring fiber laser based on such a SA. The central wavelength of the output conventional solitons is 1563.5 nm, and the pulse width is as short as 473 fs at the fundamental frequency of 19.53 MHz. The central wavelength of the tightly bound solitons is 1563.5 nm, with a pulse width of 636 fs and a separation of 1.89 ps. The device is featured with a simple and robust structure and stable operation capability and can effectively overcome the difficulty in requirement of precise control of the GIMF length, which make it attractive in ultrafast lasers and optical fiber communication systems.

Multimode fiber surface plasmon resonance sensor based on a down-up taper.

A multimode fiber surface plasmon resonance sensor based on a down-up taper for refractive index measurement is proposed and demonstrated. The device is fabricated by splicing two multimode fibers in a heating and pushing process to form an up taper, followed by heating and pulling the fiber adjacent to the up-taper area to form a down taper, and then using a magnetron sputtering technique to deposit a Cr + Ag layer of 50 nm on the surface of the down-up taper. Such a structure effectively increases the taper ratio and hence improves the measurement sensitivity. The experimental results obtained show that in the refractive index range of 1.345-1.375, the refractive index sensitivity achieved is ∼3264.01 nm/RIU. The device has a compact size and its entire length is ∼2.75 mm. Moreover, the robustness of the device is better than that of the previously reported fiber surface plasmon resonance sensors due to its relatively large waist diameter of 40 µm for the down taper. The device is expected to have potential applications in biological and chemical sensing.

Long-period fiber grating based on inner microholes in optical fiber.

A new, to the best of our knowledge, type of long-period fiber grating based on inner microholes in an optical fiber core is proposed and demonstrated. The device is fabricated by first using a femtosecond laser to write a series of vertical short line structures in the core of a single-mode fiber, followed by discharge of the short line areas with a fusion splicer. Owing to the high temperature generated, the line structure rapidly expands and forms an inner microhole. The device is found to have good high temperature sustainability up to 1000°C, with a sensitivity of approximately 13 pm/°C and its strain and bending sensitivities are approximately -1.57 pm/µÉ› and -5.198 dB/m-1, in the ranges of 0-800 µÉ› and 0-0.77 m-1, respectively. It is expected that the device can contribute to the multi-parameter sensing and detection of high temperature in harsh environments.

Ultra-short long-period fiber grating based on a micro air-channel structure.

A new type of long-period fiber grating is proposed and demonstrated. The structure of the device consists of a few micro air-channels along a single-mode fiber, and is fabricated by using a femtosecond laser to inscribe a few groups of fiber inner waveguide arrays followed by hydrofluoric acid etching. The length of the long-period fiber grating is down to 600 µm, corresponding to only five grating periods. To the best of our knowledge, this is the shortest long-period fiber grating reported. The device has a good refractive index sensitivity of ∼587.08 nm/RIU (refractive index unit) in the refractive index range of 1.34-1.365 and a relatively small temperature sensitivity of ∼12.1 pm/°C, thus reducing the temperature cross-sensitivity. Such a device is expected to have promising photonic applications.

Microfiber sensor probe integrated with a cascaded Fabry-Perot interferometer.

Developing micrometer-nanometer size optical fiber sensors has promising application prospects in microenvironments, such as biological cells, micro robots, and microfluids. We propose a new strategy to fabricate a microfiber sensor probe (MSP). A femtosecond laser was applied to integrate cascaded Fabry-Perot interferometers (FPIs) into a silica microfiber. And a MSP with diameter of ∼8µm, extinction ratio of 15 dB, fitness of 24.6, and Q-factor of 2310 was demonstrated in the experiment. In addition, the MSP was applied for the refractive index and thermal measurement and the sensitivity was observed to be 10 pm/°C and 18.5 nm/RIU. The two-beam approximation model was applied to analyze the spectrum, and simulations were taken to research the refractive index sensitivity influenced by the fiber size.

[Evaluation of adhesive bone conduction hearing aid in pediatric patients with unilateral congenital aural atresia].

Objective: To evaluate the auditory efficacy and subjective satisfaction of adhesive bone conduction hearing aid in children with unilateral congenital aural atresia (UCAA). Methods: Ten subjects (5 males and 5 females) diagnosed with UCAA with an average age of 8.3 years old (ranged from 5 to 15) were included in Beijing Tongren Hospital, Capital Medical University from January to August 2019. The free sound field hearing threshold, word recognition score in quiet, speech reception threshold in noise and sound localization ability (results were measured by RMS error) tests were performed in unaided and aided situation, respectively. Subjective satisfaction questionnaires were also distributed to subjects. Paired t test and Wilcoxon signed rank test were used as statistical analysis methods. Results: The average hearing threshold in aided condition was improved by (21.9±4.4) dB (t=15.8，P<0.05). Speech recognition abilities were generally improved both under quiet and noise (P<0.05);however, when the binaural summation, squelch and head shadow effects were analyzed respectively, the binaural squelch effect was not statistically improved (P>0.05), while the other effects were improved in aided condition (P<0.05). In sound localization test, there was no significant difference of the RMS error value between the unaided and aided situation (P>0.05). The subjects got high satisfaction rates in three subjective questionnaires. Conclusion: The adhesive bone conduction hearing aid can provide significant audiological benefit for children with UCAA as well as raising the quality of their life.

Coupling scheme for graphene saturable absorber in a linear cavity mode-locked fiber laser.

A saturable absorber based on a graphene layer covered single-mode fiber with inner short waveguides is proposed and demonstrated for a linear cavity Er-doped mode-locked fiber laser. A pair of short waveguides is written in the fiber by using femtosecond micromachining technology, and the propagating light is guided by one short waveguide to the cladding-air interface and interacts with the graphene layer in the form of evanescent waves before being collected back to the core by another short waveguide, and, as a result, the saturable absorption is excited. The designed saturable absorber is used in the passively mode-locked fiber laser to generate traditional soliton mode-locked pulse output with the center wavelength of 1564.9 nm and pulse width of 758 fs at the fundamental frequency of 22.58 MHz. The fabricated saturable absorber device is stable in operation, compact in structure, safe for thermal damage, and can effectively overcome the shortcomings of poor robustness of the saturable absorbers based on a tapered fiber and D-shaped fiber. This provides a new optical coupling scheme for saturable absorbers based on 2D materials such as graphene and has great potential application in the field of ultrashort pulse lasers.

[Effect of γ-secretase inhibitor on middle ear ultrastructures in ovalbumin-mediated otitis media with effusion in rats].

Objective: To study the effect of the inhibitor of Notch signaling pathway-γ-secretase inhibitor DAPT on the ultrastructures of middle ear in the ovalbumin (OVA)-mediated allergic OME in vivo. Methods: Male Sprague-Dawley (SD) rats, weighing 250-300 g, were completely and randomly divided into three groups (5 rats, 10 ears in each group):(1)Control group(2)OME group(3)OME+DAPT group. Rats in the OME group underwent systemic and local sensitization by intraperitoneal and intratympanic injection of ovalbumin to make the model of OVA-induced OME. Rats in the control group were sensitized with PBS. On the basis of establishing the OME model, OME+DAPT group were intraperitoneal injected with DAPT (10 mg/kg) for seven consecutive days and were administered before intratympanic injection of ovalbumin. After the model was successfully established, endoscopy,H&E staining and scanning electron microscopy were used to study the histology and mucous-ciliary ultrastructures of the non-ciliated and ciliated mucosa in the middle ear of each group. One-way ANOVA and Tukey methods were used for statistical analysis. Results: H&E staining showed that the three groups had statistically significant differences in submucosal thickness both in non-ciliated and ciliated regions (non-ciliated area:(6.83±1.47)µm, (38.58±9.57)µm, (32.17±11.89)µm, respectively. F=107.9;cilia area:(26.69±3.22)µm, (30.41±6.75)µm, (26.76±4.06)µm, respectively. F=5.62,both P<0.01). The thickness of the submucosa in the non-ciliated area and the cilia area of the OME group were significantly thicker than that of control group (F=42.08 and 4.40,both P<0.05); the thickness of the non-ciliated area and the ciliated area in OME+DAPT group were reduced compared to OME group(F=1.55 and 2.77,both P<0.05). Scanning electron microscopy showed that the array of cilia on the middle ear mucosa was disorderly arranged and inversed, this phenomenon was relieved in the OME+DAPT group. The number of goblet cells in the control group, OME group, and OME+DAPT group were 9.87±1.92; 15.67±5.77; 10.33±1.99 respectively and the difference between them was statistically significant (F=11.43, P<0.01). The number of goblet cells in the OME group were significantly higher than those in the control group (F=9.00,P<0.01) and the number of goblet cells in the OME+DAPT group were decreased compared to those of OME group (F=8.41, P<0.01). Conclusions: The study demonstrates the pathological changes of the ultrastructure in middle ear in OVA-induced OME and the effect of the γ-secretase inhibitor on it. In OME group, the cilia are disorderly arranged and inversed, the number of goblet cell is increased and they are swelled which suggest the hypersecretion of the mucus. DAPT can regulate OVA-induced allergic inflammation and relieve pathological changes of ultrastructure in middle ear mucociliary transport system through alleviating submucosal inflammation, reducing the hypersecretion of goblet cell and the morphological damage of cilia through the Notch signaling pathway.

Ultra-high sensitivity strain sensor based on biconical fiber with a bulge air-bubble.

An ultra-high sensitivity Fabry-Perot interferometer (FPI) strain sensor is proposed and experimentally demonstrated. It is composed of a biconical fiber with a bulge air-bubble at its waist. Because of the good stress concentration capability of the tapered fiber, the bulge air-bubble is easily deformed when it is stressed, resulting in an ultra-high strain sensitivity of 101.7 pm/µÉ›, which is the highest strain sensitivity among the direct wavelength interrogation-based strain sensors reported so far, to the best of our knowledge. Moreover, the proposed sensor has a low temperature sensitivity of ∼1pm/∘C; thus an extreme low temperature cross sensitivity of less than 10 nɛ/°C can be achieved.

[Effect of the surgical treatment of maxillary medication-related osteonecrosis of the jaw].

Objective: To explore the methods and clinical effects of the surgery for treating maxillary medication-related osteonecrosis of the jaw (MRONJ). Methods: The clinical data including gender, age, stage of lesion, treatment method and prognosis of 28 patients with maxillary MRONJ who underwent surgical treatment in the Department of Oral and Maxillofacial Surgery of Medical School of Nanjing University from January 2013 to October 2020 were retrospectively analyzed. There were 20 males and 8 females. The mean age at onset was (65.6±11.1) years old. According to the guidelines of American Association of Oral and Maxillofacial Surgeons, the patients' lesions were divided into 2 or 3 stages. Ten cases of stage 2 lesions were tightly sutured after partial jaw resection. Among them, 4 lesions were sutured directly with mucoperiosteal flaps, 4 lesions were covered by adjacent flaps and 2 lesions was covered by buccal fat pad flaps and adjacent flaps. Eighteen cases of stage 3 lesions were treated with sequestrectomy and drainage channels were formed. Patients were followed up regularly after the surgery, and the effect of surgical treatment was judged according to the clinical criteria such as clinical manifestations, local oral examination, imaging examination etc. Results: After follow-up for 12 to 52 months, the postoperative pain score (1.20±2.53) was significantly lower than preoperative pain score (6.70±0.95) (P<0.05) in stage 2 patients. Eight patients' mucosa healed completely without new dead bone formed. Two patients had recurrence and developed to stage 3 at the time of revisit. There were 18 cases of stage 3 lesions, which formed drainage channels after removal of the dead bone. The postoperative follow-up time was 2 to 67 months, and the symptoms of inflammation and infection disappeared. Postoperative pain score (3.40±0.51) was significantly lower than preoperative pain score (7.06±1.00) (P<0.05). Conclusions: Soft tissue flap closure of wound after partial maxillectomy is an effective approach for the treatment of maxillary MRONJ stage 2 lesions, while maxillary stage 3 lesions could be treated for eliminating clinical symptoms and improving the quality of life when establishing unobstructed drainage after dead bone extraction.

[Bonebridge implantation combined with simultaneous bilateral auricle reconstruction for bilateral congenital aural atresia].

Objective: To investigate the feasibility and safety of auricle reconstruction combined with Bonebridge implantation for bilateral aural atresia patients. Methods: A retrospective analysis was conducted for 36 cases(72 ears) who underwent Bonebridge implantation combined with bilateral auricle reconstruction from February 1, 2017 to January 15, 2020. All cases were bilateral congenital aural atresia and underwent Nagata auricle reconstruction for both sides simultaneously. Bonebridge implantations were performed during the second stage of auricle reconstruction. Results: All 36 patients healed well and had no surgical complications when discharged. The preoperative average bone conduction threshold of the patients was(8.5±5.8) dB HL and postoperative bone conduction threshold was (8.4±5.2) dB HL. There was no significant change after the implantation (P=0.724). The preoperative average air conduction threshold of was(64.9±7.4)dB HL and postoperative air conduction threshold was (24.0±5.3) dB HL, which had a significant change after the implantation (P<0.001). The hearing threshold with Bonebridge significantly decreased by 40.9 dB HL compared with the preoperative air conduction threshold(P<0.001). The speech recognition rate of monosyllable words, disyllabic words and short sentences in quiet environment increased by 62.5%, 63.5% and 72.2% respectively. The differences were statistically significant (P<0.001). The speech recognition rate of monosyllabic words, disyllabic words and short sentences in noise environment were significantly increased by 55.9%, 58.9% and 69.9% respectively (P<0.001). After a follow-up of 18.3 months in average, the hearing results were stable and the aesthetic outcomes were satisfied. One patient had implant rupture and healed after revision surgery. Conclusions: With an integrated surgical procedure, patients with bilateral congenital aural atresia can complete bilateral auricle reconstruction and hearing implantation within six months. This integrated surgical procedure is safe and efficient, with a stable hearing improvement and good appearance.

Simultaneous refractive index and temperature sensing based on a fiber surface waveguide and fiber Bragg gratings.

An optical fiber sensor based on a fiber surface waveguide and Bragg grating is proposed for a simultaneous refractive index (RI) and temperature sensing. The device consists of two fiber Bragg gratings fabricated by a femtosecond laser, one of which is situated in the fiber core for temperature sensing; the other is located in the fiber surface waveguide for both temperature and RI measurements. The RI and temperature sensitivities achieved are 10.3 nm/RIU and 9.94 pm/°C, respectively. The device is featured with a compact structure, high robustness, and convenient operation.

High-power synchronous multi-wavelength solitons from a multimode mode-locked fiber laser system.

In this Letter, we implement a multimode fiber (MMF) laser system mode-locked by a nonlinear polarization rotation technique for controllable synchronous multi-wavelength soliton generation. The synchronization of the repetition rates for different wavelengths is realized by the special mode transmission in MMF. For dual-wavelength mode-locking at 1566.7 nm and 1617.2 nm, each of the synchronously mode-locked solitons consists of a train of quasi-periodic beat pulses with a pulse width of 84 fs and period of 162 fs. The total output power reaches 532 mW with optimally balanced two-color intensities. Furthermore, switchable dual- and tri-wavelength synchronized femtosecond pulses are also obtained. In contrast to previous reports, this synchronously mode-locked multi-wavelength is output directly from a laser oscillator, which provides a simpler candidate to achieve pulse synchronization.

Optical fiber surface waveguide with Fabry-Perot cavity for sensing.

A parallel structured optical fiber Fabry-Perot interferometer sensor is proposed and demonstrated for refractive index and strain sensing with low temperature cross sensitivity. The device consists of two Fabry-Perot cavities fabricated by a femtosecond laser: one is inscribed in the fiber surface waveguide and used for sensing, and the other one is located in the fiber core for referencing. Part of the light propagating in the fiber core can be directed to the fiber surface waveguide via an X coupler. Because of the evanescent field, the light traveling along the fiber surface waveguide interacts with the surrounding medium and enables external refractive index sensing. The measurement sensitivity of the device is enhanced due to the Vernier effect associated with the parallel structured two Fabry-Perot interferometers. The sensitivities of ∼843.3nm/RIU and ∼101.8pm/µÎµ have been obtained for refractive index and strain, respectively, and the corresponding temperature cross sensitivities are ∼9.6×10-6RIU/∘C and ∼7.956×10-2µÎµ/∘C, respectively. The device is featured with high robustness, compact size, and large sensitivity.

MicroRNA-362 inhibits cell growth and metastasis in glioblastoma by targeting MAPK1.

OBJECTIVE: Glioblastoma (GBM) is a deadly brain cancer that seriously threatens the lives of patients. Moreover, various microRNAs (miRNAs) have been found to be involved in the progression of GBM. The purpose of this study is to preliminarily elucidate the regulatory mechanism of miR-362 in GBM. PATIENTS AND METHODS: The abnormal expression of miR-362 and MAPK1 was detected by RT-qPCR or Western blot analysis in GBM tissues and cells. CCK-8 and transwell assays were performed to measure cell proliferation, migration and invasion. The relationship between miR-362 and MAPK1 was confirmed by luciferase reporter assay. RESULTS: MiR-362 expression was reduced in GBM tissues and cells. The decreased expression of miR-362 predicted poor prognosis in GBM patients. Functionally, overexpression of miR-362 inhibited the proliferation and metastasis of GBM cells. In addition, miR-362 directly targets MAPK1. MAPK1 was negatively correlated with miR-362 expression in GBM. Moreover, MAPK1 was upregulated and served as a tumor promoter in GBM. More importantly, the upregulation of MAPK1 weakened the inhibitory effect of miR-362 on cell proliferation and metastasis in GBM. CONCLUSIONS: MiR-362 restrains cell proliferation and metastasis in GBM by targeting MAPK1, indicating that miR-362 functions as a tumor suppressor in GBM.

Integrated in-fiber coupler for a whispering-gallery mode microsphere resonator.

An integrated in-fiber coupler is proposed and demonstrated, which can excite whispering-gallery mode (WGM) in a microsphere resonator. This device is fabricated firstly by using femtosecond laser micromachining and a fusing splicing technique to create an inner air cavity with a suspended fiber core, then an open micro-channel is drilled on the top of the inner air cavity, and finally a microsphere is placed inside the air cavity, in contact with the suspended fiber core, to excite the WGM through the evanescent field. In the transmission spectrum of the device, the slopes of the two asymmetric Fano resonance lines of 41.12 dB/nm and $ - {18.46}\;{\rm dB/nm}$-18.46dB/nm, respectively, and a symmetrical Lorentz line with a quality factor of ${9.32} \times {{10}^3}$9.32×103 can be obtained simultaneously. Such an in-fiber WGM microsphere resonator has the advantages of compact structure, convenient operation, and high durability.

Parallel structured optical fiber in-line Fabry-Perot interferometers for high temperature sensing.

We propose and demonstrate parallel structured optical fiber in-line Fabry-Perot interferometers for high temperature sensing. The device consists of three Fabry-Perot cavities in parallel connection, which allows three independent fringe patterns superimposed at its output, and, as a result, a number of dominant fringe peaks/dips appear, thus enabling unambiguous measurement in a large range. The device is featured with compact size, robust structure, and excellent high temperature sustainability, which makes it promising in extreme environment monitoring.