Showing papers on "Mach–Zehnder interferometer published in 2015"
TL;DR: The turning point of the refractive index (RI) sensitivity based on the multimode microfiber (MMMF) in-line Mach-Zehnder interferometer (MZI) is observed and theoretical analysis demonstrates that the RI sensitivity will reach ±∞ on either side of the turning point due to the group effective RI difference approaching zero.
Abstract: The turning point of the refractive index (RI) sensitivity based on the multimode microfiber (MMMF) in-line Mach-Zehnder interferometer (MZI) is observed. By tracking the resonant wavelength shift of the MZI generated between the HE(11) and HE(12) modes in the MMMF, the surrounding RI (SRI) could be detected. Theoretical analysis demonstrates that the RI sensitivity will reach ±∞ on either side of the turning point due to the group effective RI difference (G) approaching zero. Significantly, the positive sensitivity exists in a very wide fiber diameter range, while the negative sensitivity can be achieved in a narrow diameter range of only 0.3 μm. Meanwhile, the experimental sensitivities and variation trend at different diameters exhibit high consistency with the theoretical results. High RI sensitivity of 10777.8 nm/RIU (RI unit) at the fiber diameter of 4.6 μm and the RI around 1.3334 is realized. The discovery of the sensitivity turning points has great significance on trace detection due to the possibility of ultrahigh RI sensitivity.
120 citations
TL;DR: A Mach-Zehnder interferometer based on a twin-core fiber that exhibited a high gas pressure sensitivity and a low temperature cross-sensitivity makes it very suitable for highly-sensitive gas pressure sensing in harsh environments.
Abstract: A Mach-Zehnder interferometer based on a twin-core fiber was proposed and experimentally demonstrated for gas pressure measurements. The in-line Mach-Zehnder interferometer was fabricated by splicing a short section of twin-core fiber between two single mode fibers. A micro-channel was created to form an interferometer arm by use of a femtosecond laser to drill through one core of the twin-core fiber. The other core of the fiber was remained as the reference arm. Such a Mach-Zehnder interferometer exhibited a high gas pressure sensitivity of −9.6 nm/MPa and a low temperature cross-sensitivity of 4.4 KPa/°C. Moreover, ultra-compact device size and all-fiber configuration make it very suitable for highly-sensitive gas pressure sensing in harsh environments.
112 citations
TL;DR: Numerical results show that extremely large optical confinement factor of the tested analytes can be obtained by DSHP waveguide with optimized geometrical parameters, which is larger than both, conventional SOI waveguides and plasmonic slot waveguide with same widths.
Abstract: A Mach-Zehnder Interferometer (MZI) liquid sensor, employing ultra-compact double-slot hybrid plasmonic (DSHP) waveguide as active sensing arm, is developed. Numerical results show that extremely large optical confinement factor of the tested analytes (as high as 88%) can be obtained by DSHP waveguide with optimized geometrical parameters, which is larger than both, conventional SOI waveguides and plasmonic slot waveguides with same widths. As for MZI sensor with 40μm long DSHP active sensing area, the sensitivity can reach as high value as 1061nm/RIU (refractive index unit). The total loss, excluding the coupling loss of the grating coupler, is around 4.5dB.
103 citations
TL;DR: A new type of hybrid atom-light interferometers with two atomic Raman amplification processes (RA1 and RA2) replacing the beam splitting elements in a traditional interferometer is demonstrated, which is a sensitive probe of the atomic internal state and should find wide applications in precision measurement and quantum control with atoms and photons.
Abstract: A new type of hybrid atom-light interferometer is demonstrated with atomic Raman amplification processes replacing the beam splitting elements in a traditional interferometer. This nonconventional interferometer involves correlated optical and atomic waves in the two arms. The correlation between atoms and light developed with the Raman process makes this interferometer different from conventional interferometers with linear beam splitters. It is observed that the high-contrast interference fringes are sensitive to the optical phase via a path change as well as the atomic phase via a magnetic field change. This new atom-light correlated hybrid interferometer is a sensitive probe of the atomic internal state and should find wide applications in precision measurement and quantum control with atoms and photons.
92 citations
TL;DR: A compact and highly-sensitive curvature sensor based on a Mach-Zehnder interferometer created in a photonic crystal fiber that exhibited a high curvature sensitivity and a temperature sensitivity suitable for high-sensitivity curvature sensing in harsh environments is demonstrated.
Abstract: We demonstrated a compact and highly-sensitive curvature sensor based on a Mach-Zehnder interferometer created in a photonic crystal fiber. Such a Mach-Zehnder interferometer consisted of a peanut-like section and an abrupt taper achieved by use of an optimized electrical arc discharge technique, where only one dominating cladding mode was excited and interfered with the fundamental mode. The unique structure exhibited a high curvature sensitivity of 50.5 nm/m-1 within a range from 0 to 2.8 m-1, which made it suitable for high-sensitivity curvature sensing in harsh environments. Moreover, it also exhibited a temperature sensitivity of 11.7 pm/°C.
82 citations
TL;DR: In this article, a simple, ultra compact and highly sensitive photonic crystal fiber interferometer (PCFI) for external refractive index (ERI) sensing was proposed and demonstrated.
Abstract: A simple, ultra compact and highly sensitive photonic crystal fiber interferometer (PCFI) for external refractive index (ERI) sensing was proposed and demonstrated in this paper. The PCFI was formed by splicing photonic crystal fiber (PCF) between two single mode fibers (SMFs) with a slight core-offset. The both joints were up-tapered joints which acted as mode splitter/combiner and were made by fusion tapering technique. The Mach–Zehnder interferometer (MZI) incorporated intermodal interference between core mode and cladding modes of the PCF. When the ERI changed, a RI variation of cladding modes would occur and the output interference spectrum would shift. By measuring the wavelength shift of the interference pattern, temperature-insensitive RI measurement could be achieved. In addition, the refractive index sensing properties with the different PCF diameters were also investigated experimentally. Experimental results showed that RI sensitivity could be up to 252 nm/RIU in the refractive index range of 1.333–1.379. And it could be anticipated that RI sensitivity could be improved if the PCF diameter continues to decrease. Meanwhile, the sensor had the advantages of simple structure, small size, high sensitivity, low cost and low temperature sensitivity.
82 citations
TL;DR: A fiber in-line Mach-Zehnder interferometer based on an inner air-cavity with open micro-channel for high-pressure sensing applications and exhibits a high pressure sensitivity of ∼8,239 pm/MPa.
Abstract: We demonstrate a fiber in-line Mach–Zehnder interferometer based on an inner air-cavity with open micro-channel for high-pressure sensing applications. The inner air-cavity is fabricated by combining femtosecond laser micromachining and the fusion splicing technique. The micro-channel is drilled on the top of the inner air-cavity to allow the high-pressure gas to flow in. The fiber in-line device is miniature, robust, and stable in operation and exhibits a high pressure sensitivity of ∼8,239 pm/MPa.
72 citations
TL;DR: In this paper, a compact optical fiber Mach-Zehnder interferometer (MZI) is proposed and experimentally demonstrated for simultaneous measurement of temperature and strain or temperature and curvature.
70 citations
TL;DR: In this paper, a highly sensitive refractive index (RI) sensor based on all-fiber Mach-Zehnder interferometer (MZI) was simulated and demonstrated by splicing a section of single mode fiber (SMF) between two SMFs with a slight core offset at two splicing joints.
Abstract: A highly sensitive refractive index (RI) sensor based on all-fiber Mach–Zehnder interferometer (MZI) was simulated and demonstrated. It was fabricated by splicing a section of single mode fiber (SMF) between two SMFs with a slight core offset at two splicing joints, which were used to excite cladding modes and couple the core mode to cladding modes. And then the interference between the core and cladding modes was utilized to measure sounding RI and the sensitivity of the sensor was enhanced by tapering fiber. Experimental results showed that the measured RI sensitivity could be up to 78.7 nm/RIU in the range of 1.333–1.374. Meanwhile, the sensor has the advantages of simple structure, small size, high sensitivity and low cost.
67 citations
TL;DR: In this article, a robust refractive index (RI) sensor based on a tapered photonic crystal fiber (PCF) Mach-Zehnder interferometer (MZI) was proposed.
Abstract: A compact and robust refractive index (RI) sensor based on a tapered photonic crystal fiber (PCF) Mach–Zehnder interferometer (MZI) was proposed. It consists of a section of tapered PCF which is spliced between two single-mode fibers (SMF). A strong evanescent field was formed near the tapered region and made it susceptible to external RI variations. The interference was utilized between core modes and cladding modes of the PCF. Experimentally, the sensor exhibits highly RI sensitivity which is found to be 51.902 nm/RIU within a range from 1.3411 to 1.3737. A resolution of 1.93 × 10−5 RIU was achieved since the OSA has a resolution of 1 pm. In addition, a PDMS detection cell is specially designed to increase the stability and robustness of the device. The temperature effect of the sensor is also analyzed. The proposed all-fiber RI sensor based on tapered PCF is attractive due to its compact size, low cost and immunity to electromagnetic interference beyond what conventional refractive index sensors can offer.
67 citations
TL;DR: In this paper, an all-fiber sensor for simultaneous measurement of temperature and refractive index (RI) is proposed and demonstrated, which is composed of a Mach-Zehnder interferometer (MZI) and a fiber Bragg grating (FBG).
TL;DR: In this paper, an approach to realize simultaneous measurement of refractive index (RI) and temperature based on a microfiber-based dual inline Mach-Zehnder interferometer (MZI) is proposed and demonstrated.
Abstract: An approach to realizing simultaneous measurement of refractive index (RI) and temperature based on a microfiber-based dual inline Mach–Zehnder interferometer (MZI) is proposed and demonstrated. Due to different interference mechanisms, as one interference between the core mode and the lower order cladding mode in the sensing single-mode fiber and the other interference between the fundamental mode and the high-order mode in the multimode microfiber, the former interferometer achieves RI sensitivity of $-$ 23.67 nm/RIU and temperature sensitivity of 81.2 pm/oC, whereas those of the latter are 3820.23 nm/RIU, and $-$ 465.7 pm/oC, respectively. The large sensitivity differences can provide a more accurate demodulation of RI and temperature. The sensor is featured with multiparameters measurement, compact structure, high sensitivity, low cost, and easy fabrication.
TL;DR: In this paper, the authors theoretically investigated the thermoelectric properties of heat engines based on Mach-Zehnder interferometers and found that the energy dependence of the transmission amplitudes in such setups arises from a difference in the interferometer arm lengths.
Abstract: We theoretically investigate the thermoelectric properties of heat engines based on Mach-Zehnder interferometers. The energy dependence of the transmission amplitudes in such setups arises from a difference in the interferometer arm lengths. Any thermoelectric response is thus of purely quantum-mechanical origin. In addition to an experimentally established three-terminal setup, we also consider a two-terminal geometry as well as a four-terminal setup consisting of two interferometers. We find that Mach-Zehnder interferometers can be used as powerful and efficient heat engines which perform well under realistic conditions.
TL;DR: The hybrid Mach-Zehnder interferometers show a higher sensitivity to hydrogen gas than a single-nanowire sensing approach, and the lengths of PdAu nanowires used are less than 20 μm, which are 2 or 3 orders of magnitude shorter than the lengthsof Pd coatings in existing fiber-optic hydrogen sensors.
Abstract: By using PdAu nanowires as plasmonic waveguides, hybrid photon–plasmon Mach–Zehnder interferometers by integrating single-crystal PdAu alloy nanowires with silica optical microfibers are demonstrated. Based on an evanescent wave coupling technique using optical fiber tapers, surface plasmon polaritons are efficiently excited and propagated in suspended PdAu nanowires. The interference spectra show attractive properties such as broad and flexible in situ tunability with wavelength spacings ranging from ∼1 to tens of nanometers, and high extinction ratios of over 20 dB. The hybrid Mach–Zehnder interferometers show a higher sensitivity to hydrogen gas than a single-nanowire sensing approach, and the lengths of PdAu nanowires used are less than 20 μm, which are 2 or 3 orders of magnitude shorter than the lengths of Pd coatings in existing fiber-optic hydrogen sensors. Other advantages including good reversibility and low-power operation are also obtained.
TL;DR: In this article, a new liquid level sensor based on in fiber Mach-Zehnder interferometer (MZI) is proposed and demonstrated, which is formed by cascading two peanut-shaped fiber structures in singlemode fiber.
Abstract: A new liquid level sensor based on in fiber Mach-Zehnder interferometer (MZI) is proposed and demonstrated. The MZI is formed by cascading two peanut-shaped fiber structures in single-mode fiber. In the water level experiment, the sensitivities of sensors with lengths of 53.5 and 75.4 mm are -0.1025 and -0.0279 nm/mm, respectively. The absolute value of sensitivity increases with the refractive index of liquid. The MZI presented in this paper has advantages of low cost and ease of fabrication, which can be a potential advantage in the liquid level measurement.
TL;DR: A methane sensor based on an integrated Mach-Zehnder interferometer, which is cladded by a styrene-acrylonitrile film incorporating cryptophane-A, results in a detection limit as low as 17 ppm, 1-2 orders of magnitude lower than typically achieved with chip-scale low-cost sensors.
Abstract: We report a methane sensor based on an integrated Mach-Zehnder interferometer, which is cladded by a styrene-acrylonitrile film incorporating cryptophane-A. Cryptophane-A is a supramolecular compound able to selectively trap methane, and its presence in the cladding leads to a 17-fold sensitivity enhancement. Our approach, based on 3 cm-long low-loss Si3N4 rib waveguides, results in a detection limit as low as 17 ppm. This is 1-2 orders of magnitude lower than typically achieved with chip-scale low-cost sensors.
TL;DR: In this paper, a hybrid integration platform consisting of arbitrarily designed waveguide circuits and single-photon sources was demonstrated. But the authors did not specify the number of channels to be accessed.
Abstract: Fundamental to integrated photonic quantum computing is an on-chip method for routing and modulating quantum light emission. We demonstrate a hybrid integration platform consisting of arbitrarily designed waveguide circuits and single-photon sources. InAs quantum dots (QD) embedded in GaAs are bonded to a SiON waveguide chip such that the QD emission is coupled to the waveguide mode. The waveguides are SiON core embedded in a SiO2 cladding. A tuneable Mach Zehnder interferometer (MZI) modulates the emission between two output ports and can act as a path-encoded qubit preparation device. The single-photon nature of the emission was verified using the on-chip MZI as a beamsplitter in a Hanbury Brown and Twiss measurement.
TL;DR: In this article, a compact wavelength-division (de)multiplexer is proposed and demonstrated experimentally to achieve doubled channel number and halved channel spacing by utilizing a bidirectional arrayed-waveguide grating integrated with an Mach-Zehnder interferometer optical interleaver.
Abstract: A compact wavelength-division (de)multiplexer is proposed and demonstrated experimentally to achieve doubled channel number and halved channel spacing by utilizing a bidirectional arrayed-waveguide grating integrated with an Mach–Zehnder interferometer optical interleaver. As an example, an 18-channel wavelength-division (de)multiplexer with a channel spacing of 200 GHz is designed and fabricated. The measured excess loss is about 8 dB and the channel crosstalk is −15 ∼ −18 dB. The footprint of this fabricated (de)multiplexer is about 520 μm × 190 μm.
TL;DR: In this article, a bend-insensitive fiber Mach-Zehnder interferometer operating in both guided and leaky mode domains is investigated for the first time to the best of our knowledge.
Abstract: Refractometry based on a tapered bend-insensitive fiber Mach–Zehnder interferometer operating in both guided and leaky mode domains is investigated for the first time to our knowledge. We propose a novel approach that allows for refractive index measurement by monitoring power changes in leaky outer-cladding modes, and simultaneous phase-based temperature detection using inner-cladding modes, which remain guided. The proposed scheme is used to extend the operating range of a fiber-optic MZI refractive index sensor into the regime in which outer cladding modes become leaky, a domain previously inaccessible to similar sensors given the complex nature of the phase dependence exhibited by leaky modes on external refractive index. The experimental results agree well with theoretical predictions, and demonstrate the potential of in-fiber refractometers for high-sensitivity sensing over large measuring ranges.
TL;DR: Efficient application of the electro-optic effect in a lithium-niobate-based Mach-Zehnder interferometer to construct universal gates has been demonstrated.
Abstract: Efficient application of the electro-optic effect in a lithium-niobate-based Mach-Zehnder interferometer to construct universal gates has been demonstrated. The study is carried out by simulating the proposed device with the beam propagation method, and the results are verified using MATLAB. Various parameters influencing the performance of the device (such as speed, latency, and power consumption) also have been taken into account.
TL;DR: Due to high coupling efficiency of SOI rib waveguide with large cross section with standard single-mode glass optical fiber, the proposed MZI sensing platform can be conveniently integrated with optical fiber communication systems and (opto-) electronic systems, and therefore has the potential to realize remote sensing, in situ real-time detecting, and possible applications in the internet of things.
Abstract: A high-sensitivity Mach-Zehnder interferometer (MZI) biochemical sensing platform based on Silicon-in-insulator (SOI) rib waveguide with large cross section is proposed in this paper. Based on the analyses of the evanescent field intensity, the mode polarization and cross section dimensions of the SOI rib waveguide are optimized through finite difference method (FDM) simulation. To realize high-resolution MZI read-out configuration based on the SOI rib waveguide, medium-filled trenches are employed and their performances are simulated through two-dimensional finite-difference-time domain (2D-FDTD) method. With the fundamental EH-polarized mode of the SOI rib waveguide with a total rib height of 10 μm, an outside rib height of 5 μm and a rib width of 2.5 μm at the operating wavelength of 1550 nm, when the length of the sensitive window in the MZI configuration is 10 mm, a homogeneous sensitivity of 7296.6%/refractive index unit (RIU) is obtained. Supposing the resolutions of the photoelectric detectors connected to the output ports are 0.2%, the MZI sensor can achieve a detection limit of 2.74 × 10−6 RIU. Due to high coupling efficiency of SOI rib waveguide with large cross section with standard single-mode glass optical fiber, the proposed MZI sensing platform can be conveniently integrated with optical fiber communication systems and (opto-) electronic systems, and therefore has the potential to realize remote sensing, in situ real-time detecting, and possible applications in the internet of things.
IBM1
TL;DR: In this article, the authors present simulation and experimental results on a silicon photonic strictly nonblocking $4\times 4$ electrooptic Mach-Zehnder-based switch fabric.
Abstract: We present simulation and experimental results on a silicon photonic strictly nonblocking $4\times 4$ electrooptic Mach–Zehnder-based switch fabric. We propose a simulation framework based on the transfer matrix approach that enables calculating the transmission spectra of any type of multistage interconnect switch network. The model is used to analyze the spectral characteristics of the switch fabric. We also show experimental results on a fabric designed and fabricated in IBM's 90-nm photonics-enabled CMOS process. The fabric monolithically integrates the CMOS logic, the switch drivers, and all the photonics. We fully characterized all the transmittances of the switch and demonstrate onchip insertion loss between 1.5 and 3 dB and a crosstalk less than –25 dB for all the signal paths.
TL;DR: In this paper, a hybrid integration platform consisting of arbitrarily designed waveguide circuits and single photon sources was demonstrated. But the single photon nature of the emission was verified by an on-chip Hanbury Brown and Twiss measurement.
Abstract: Fundamental to integrated photonic quantum computing is an on-chip method for routing and modulating quantum light emission. We demonstrate a hybrid integration platform consisting of arbitrarily designed waveguide circuits and single photon sources. InAs quantum dots (QD) embedded in GaAs are bonded to an SiON waveguide chip such that the QD emission is coupled to the waveguide mode. The waveguides are SiON core embedded in a SiO2 cladding. A tuneable Mach Zehnder modulates the emission between two output ports and can act as a path-encoded qubit preparation device. The single photon nature of the emission was verified by an on-chip Hanbury Brown and Twiss measurement.
TL;DR: The paper provides the elementary theory about the electro-optic effects and describes efficient techniques to implement the electrical binary to optical gray code converters and even parity checkers using appropriate configuration of electro-Optic based MZIs as basic building blocks.
Abstract: The Mach–Zehnder interferometer (MZI) structures working on the principle electro-optical effect shows the powerful ability to switch the optical signal from one output port to the another output port. Hence, it is possible to construct some complex optical combinational digital circuits using the electro-optic effect based MZI structure as a basic building block. The implementation of electrical binary to optical gray code converters and even parity checkers can improve the performance of the digital logic circuits. The paper provides the elementary theory about the electro-optic effects and describes efficient techniques to implement the electrical binary to optical gray code converters and even parity checkers using appropriate configuration of electro-optic based MZIs as basic building blocks. The paper includes the detailed mathematical derivation and corresponding MATLAB simulation result related to the optical switching phenomena of MZI structure. The paper describes the efficient techniques to implement the electrical binary to optical gray code converters and even parity checkers with the suitable mathematical expression and relevant MATLAB results. The proposed devices are verified with the appropriate optiBPM software. Finally, the paper shows the detailed analysis to check the appropriate device parameters such as Ti-thickness, switching voltages in order to obtain the optimum performance parameters such as cross-talk, extinction ratio and losses through the linear and curved waveguide section.
TL;DR: A fiberized refractive index (RI) Mach-Zehnder interferometer (MZI) based on a micro V-shaped slot in fiber core is fabricated in a standard single mode optical fiber by femtosecond laser machining and chemical etching.
Abstract: A fiberized refractive index (RI) Mach–Zehnder interferometer (MZI) based on a micro V-shaped slot in fiber core is fabricated in a standard single mode optical fiber by femtosecond laser machining and chemical etching. The interference fringe of the MZI would shift with the variation of the ambient RI. The experimental results show that the RI sensitivity for the sensor is about −104 nm/RIU (refractive index unit) within the RI range between 1.332 and 1.352. Its robust structure and high sensitivity will have attractive potential application in chemical, biological and environmental monitoring.
TL;DR: The interferometric crosstalk and system performance of two optical add-drop multiplexer (OADM) designs based on Bragg grating/Mach-Zehnder interferometers implemented in silicon-on-insulator are characterized.
Abstract: We characterize the interferometric crosstalk and system performance of two optical add-drop multiplexer (OADM) designs based on Bragg grating/Mach-Zehnder interferometers implemented in silicon-on-insulator. Both OADM designs exhibit low crosstalk and negligible crosstalk-induced power penalties over their 3 dB bandwidths. The devices are tolerant to wavelength drift and misalignment between the transmitter and OADM; moreover, their designs can be optimized further to enable high performance operation in WDM systems.
TL;DR: This paper constitutes the mathematical description of the proposed device and thereafter compilation using MATLAB, and is carried out by simulating the proposeddevice with the beam propagation method.
Abstract: Electrical component speed is a major constraint in high-speed communications. To overcome this constraint, electrical components are now being replaced by optical components. The application of optical switching phenomena has been used to construct the design of the D flip-flop and T flip-flop based on the electro-optic effect in a Mach-Zehnder interferometer (MZI). The MZI structures show the powerful ability to switch the optical signal from one output port to the other. Hence, it is possible to construct some complex optical combinational digital circuits using the electro-optic-effect-based MZI structure as a basic building block. This paper constitutes the mathematical description of the proposed device and thereafter compilation using MATLAB. The study is carried out by simulating the proposed device with the beam propagation method.
TL;DR: In this article, the fundamental optical and electrical tradeoffs which are limiting high-speed operation of broadband depletion-type silicon Mach-Zehnder modulators (MZMs) are studied.
Abstract: Fundamental limiting factors regarding high-speed performance of broadband depletion-type silicon (Si) Mach–Zehnder modulators (MZMs) are studied. Optical and electrical measurements of MZMs with traveling wave electrodes (TWE) reveal significant dependences between optoelectrical bandwidth and design parameters. An equivalent circuit model is implemented to fit measured modulator characteristics. Using the model, the limits of TWE depletion-type Si MZM systems are studied under the requirement of specific driving voltage. By comparing phase shifters with different doping concentration or junction position, we explore the fundamental optical and electrical tradeoffs which are limiting high-speed operation.
TL;DR: In this article, the authors present an experimental demonstration of a $4 × 4$ silicon electro-optic (EO) switch fabric based on a Benes architecture, where double-ring-assisted Mach-Zehnder interferometers (DR-MZIs) are utilized as the basic switch elements.
Abstract: We present the experimental demonstration of a $4\times 4$ silicon electro-optic (EO) switch fabric based on a Benes architecture. Double-ring-assisted Mach–Zehnder interferometers (DR-MZIs) are utilized as the basic switch elements. Silicon resistive microheaters and p-i-n diodes are embedded in both of the microrings of the DR-MZIs for low-loss thermo-optic (TO) phase correction and high-speed switching operation, respectively. The TO tuning power dissipated to align all resonances is 22.37 mW. The maximum EO tuning power required to switch all DR-MZIs is only 1.38 mW. The average on-chip insertion loss is in the range of 4–5.8 dB for all switching states. The transmission spectrum measurement shows that the device can perform switching in a $\sim 35$ -GHz spectral window with the worst crosstalk being −18.4 dB.
TL;DR: The measured results demonstrate that very clear interference spectra can be obtained in a novel all-fiber Mach-Zehnder interferometer fabricated by infiltrating two separated liquid sections along a PCF.
Abstract: We propose a novel all-fiber Mach-Zehnder interferometer (MZI) fabricated by infiltrating two separated liquid sections along a PCF. Due to the reduced effective index difference between the core region and the liquid-filled cladding region, the guided field in the liquid sections possesses a larger mode field area and can simultaneously induce the core mode and cladding modes of the empty PCF to form a MZI. The measured results demonstrate that very clear interference spectra can be obtained. By increasing the length of the MZIs, the decreased average fringe spacing can be observed. We have also measured the temperature sensitivity of our proposed PCF-based MZIs. Due to the existence of the two liquid sections, the temperature sensitivities can be enlarged to −0.176nm/°C and −0.53dB/°C.