Showing papers on "Mach–Zehnder interferometer published in 2009"
TL;DR: In this paper, an approach to achieve simultaneous measurement of refractive index and temperature is proposed by using a Mach-Zehnder interferometer realized on tapered single-mode optical fiber.
Abstract: An approach to achieve simultaneous measurement of refractive index and temperature is proposed by using a Mach–Zehnder interferometer realized on tapered single-mode optical fiber. The attenuation peak wavelength of the interference with specific order in the transmission spectrum shifts with changes in the environmental refractive index and temperature. By utilizing S-band and C/L-band light sources, simultaneous discrimination of refractive index and temperature with the tapered fiber Mach–Zehnder interferometer is demonstrated with the corresponding sensitivities of −23.188 nm/RIU (refractive index unit) and 0.071 nm/ °C, and −26.087 nm/RIU (blueshift) and 0.077 nm/°C (redshift) for the interference orders of 169 and 144, respectively.
551 citations
TL;DR: In this paper, a Mach-Zehnder interferometer with two abrupt singlemode fiber tapers is simulated, constructed, and demonstrated, which has an insertion loss of 5 dB and an extinction ratio over 15 dB.
Abstract: A Mach-Zehnder interferometer with two abrupt single-mode fiber tapers is simulated, constructed, and demonstrated. The interferometer has an insertion loss of 5 dB and an extinction ratio over 15 dB. The interferometer is tested as a strain sensor based on the maximum attenuation wavelength shift with a comparable sensitivity (slope: 2000 nm/ epsiv, R 2 = 0.996) with long-period-grating-type sensor and promises low fabrication cost.
141 citations
TL;DR: A tunable and switchable multiwavelength erbium-doped fiber ring laser based on what the authors believe to be a new type of tunable comb filter is proposed and demonstrated and the dual-function operation of the channel-spacing tunability and the wavelength switching can be readily achieved.
Abstract: A tunable and switchable multiwavelength erbium-doped fiber ring laser based on what we believe to be a new type of tunable comb filter is proposed and demonstrated. By adjusting the polarization controllers, the dual-function operation of the channel-spacing tunability and the wavelength switching (interleaving) can be readily achieved. Up to 29 stable lasing lines with 0.4 nm spacing and 14 lasing wavelengths with 0.8 nm spacing in 3 dB bandwidth were obtained at room temperature. In addition, the lasing output, including the number of the lasing lines, the lasing evenness, and the lasing locations, can also be flexibly adjusted through the wavelength-dependent polarization rotation mechanism.
124 citations
TL;DR: In this article, a fiber inline Mach-Zehnder-type core-cladding-mode interferometer fabricated by two-point CO2 laser irradiations on a single-mode fiber was reported.
Abstract: We report a fiber inline Mach-Zehnder-type core-cladding-mode interferometer fabricated by two-point CO2 laser irradiations on a single-mode fiber. The laser irradiations caused efficient light coupling from the core mode to the lower order cladding modes and vise versa. High-quality interference spectra with a fringe visibility of about 20 dB were observed for four different interferometer lengths (5, 10, 20, and 40 mm). The temperature sensitivity of the device with a length of 5 mm was measured to be 0.0817 nm/degC. The sensitivity for refractive index measurement of the device was comparable with a long-period fiber grating of LP04 cladding mode.
110 citations
TL;DR: In this paper, the authors analyzed the spurious-free dynamic range (SFDR) for a radio-over-fiber system using an optical single sideband (OSSB) Mach-Zehnder modulator (MZM) that is linearized using mixed polarization.
Abstract: We analyze in theory, simulation, and experiment the spurious-free dynamic range (SFDR) for a radio-over-fiber system using an optical single sideband (OSSB) Mach-Zehnder modulator (MZM) that is linearized using mixed polarization. The mixed polarization OSSB MZM makes use of a dual-electrode z-cut LiNbO3 MZM, where a linear polarizer is placed in front and in behind the optical modulator, respectively. It is found that intermodulation distortion can be suppressed significantly regardless of modulation index. Thus intermodulation induced power fading and crosstalk via fiber chromatic dispersion for a given RF carrier is reduced compared to using the conventional OSSB MZM. Improvements of ~ 13 dB in SDFR is predicted in theory, simulation, and demonstrated experimentally.
92 citations
TL;DR: A novel intensity-based bend sensor is also demonstrated with bend-induced spatial fringe shift and high air filling fraction of fabricated TC-PCF cladding provides immunity to bend- induced intensity fluctuation.
Abstract: We will discuss fabrication of twin core photonic crystal fiber (TC-PCF) using the stack-and-draw method and its application for in-line Mach-Zehnder interferometers. The small difference in the effective indexes of the two core modes leads to interference fringes and the birefringence of the twin cores results in polarization-dependent fringe spacing. The strain sensitivity was negative and wavelength-dependent. A novel intensity-based bend sensor is also demonstrated with bend-induced spatial fringe shift. High air filling fraction of fabricated TC-PCF cladding provides immunity to bend-induced intensity fluctuation.
82 citations
TL;DR: In this article, a switchable multi-wavelength fiber ring laser with an in-fiber Mach-Zehnder interferometer incorporated into the ring cavity serving as wavelength-selective filter at room temperature is demonstrated.
Abstract: Switchable multi-wavelength fiber ring laser with an in-fiber Mach-Zehnder interferometer incorporated into the ring cavity serving as wavelength-selective filter at room temperature is demonstrated. The filter is formed by splicing a section of few-mode photonic crystal fiber (PCF) and two segments of single mode fiber (SMF) with the air-holes on the both sides of PCF intentionally collapsed in the vicinity of the splices. By adjusting the states of the polarization controller (PC) appropriately, the laser can be switched among the stable single-, dual- and triple-wavelength lasing operations by exploiting polarization hole burning (PHB) effect.
72 citations
TL;DR: It is proved to be valid that the proposed scheme is insensitive to the MZM bias drift, which demonstrates a relatively higher stability.
Abstract: We propose what we believe to be a novel method to generate optical millimeter-wave signals with frequency quadrupling using two cascaded Mach–Zehnder modulators (MZMs). Both theoretical analysis and experimental demonstration are presented. By symmetrically biasing the MZMs, without any optical filters or electrical devices, a high-quality millimeter wave at 40 GHz with an optical harmonic distortion suppression ratio of more than 25 dB is obtained. Furthermore, it is also proved to be valid that the proposed scheme is insensitive to the MZM bias drift, which demonstrates a relatively higher stability.
71 citations
TL;DR: In this paper, the general output characteristics of high quality factor microring resonators with modulated coupling strengths are derived, and the results are applied to the case of a microri integrated with a Mach-Zehnder interferometer coupler to investigate the amplitude, linearity, distortion, and chirp of the output.
Abstract: The general output characteristics of high quality factor microring resonators with modulated coupling strengths are derived. The results are applied to the case of a microring integrated with a Mach-Zehnder interferometer coupler to investigate the amplitude, linearity, distortion, and chirp of the output. These modulators can be designed to give low-distortion, high extinction ratio, chirp-free outputs at modulation rates only limited by the maximum modulation rate of the coupler or the free spectral range frequency of the resonator.
71 citations
TL;DR: By observing the wavelength shift of the peaks or valleys of the SPP interference pattern, a highly compact vertical plasmonic MZI with a potential to achieve a very high sensitivity is proposed.
Abstract: Vertical plasmonic Mach-Zehnder Interferometers are investigated theoretically and experimentally, and their potential for ultra-sensitive optical sensing is discussed. Plasmonic interferences arise from coherently coupled pairs of subwavelength slits, illuminated by a broadband optical source, and this interference modulates the intensity of the far-field scattering spectrum. Experimental results, obtained using a simple experimental setup, are presented to validate theoretically predicted interferences introduced by the surface plasmon modes on top and bottom surfaces of a metal film. By observing the wavelength shift of the peaks or valleys of the interference pattern, this highly compact device has the potential to achieve a very high sensitivity relative to other nanoplasmonic architectures reported.
70 citations
TL;DR: This work has proposed SOA-MZI-based tree architecture, a new and alternative scheme, for integrated all-optical logic and arithmetic operations, for integration of signals processing in optical interconnecting networks.
TL;DR: It is demonstrated numerically that the theoretical maximum sensitivity of a ring-coupled Mach-Zehnder interferometer optimized as a sensor is about 30% greater than the optimizedensitivity of a conventional single-bus ring sensor with an identical ring perimeter and loss.
Abstract: We demonstrate numerically that the theoretical maximum sensitivity of a ring-coupled Mach-Zehnder interferometer (MZI) optimized as a sensor is about 30% greater than the optimized sensitivity of a conventional single-bus ring sensor with an identical ring perimeter and loss. The ring-coupled MZI sensor also achieves its greater sensitivity with a 25% lower circulating power, which is useful for the suppression of undesirable nonlinear effects.
TL;DR: In this paper, a complete analysis of an analog fiber-optic link employing a lowbiased Mach-Zehnder modulator followed by optical amplification with an erbium-doped fiber amplifier is presented.
Abstract: In this paper, a complete analysis of an analog fiber-optic link employing a low-biased Mach-Zehnder modulator followed by optical amplification with an erbium-doped fiber amplifier is presented. The expressions for RF gain, RF noise figure, second- and third-order intercept points, and spurious-free dynamic range are derived. Experimental data are employed to support the analytical results, and the optimal bias points for the metrics are demonstrated.
TL;DR: In this article, the authors used an electronic Mach-Zehnder interferometer to explore the nonequilibrium coherence of the electron waves within the edge states that form in the integral quantum-Hall-effect device.
Abstract: We use an electronic Mach-Zehnder interferometer to explore the nonequilibrium coherence of the electron waves within the edge states that form in the integral quantum-Hall-effect device. The visibility of the interference as a function of bias voltage and transmission probabilities of the mirrors, which are realized by quantum point contacts, reveals an unexpected asymmetry at finite bias when the transmission probability $T$ of the mirror at the input of the interferometer is varied between 0 and 100%, while the transmission probability of the other mirror at the output is kept fixed. This can lead to the surprising result of an increasing magnitude of interference with increasing bias voltage for certain values of $T$. A detailed analysis for various transmission probabilities and different directions of the magnetic field demonstrates that this effect is not related to the transmission characteristics of a single-quantum point contact but is an inherent property of the Mach-Zehnder interferometer with edge states.
TL;DR: In this paper, a composite optical transmitter based on dual parallel Mach-Zehnder modulators is proposed to linearize double-sideband suppressed-carrier coherent analog fiber-optic links.
Abstract: A composite optical transmitter based on dual parallel Mach-Zehnder modulators is proposed to linearize double-sideband suppressed-carrier coherent analog fiber-optic links The optimization condition for achieving the best spurious-free dynamic range (SFDR) is discussed, with a simple and exact expression for the maximized SFDR being derived Unlike other existing linearization schemes, the proposed technique has the advantages of broadband operation and shot-noise-limited signal-to-noise ratio at the same time For a lossless link employing a transmitter laser with moderate optical power of 100 mW, a broadband SFDR as high as 144 dB middot Hz4/5 is theoretically predicted
TL;DR: An electronic Mach-Zehnder interferometer which has one of its two arms connected to an Ohmic contact through a quantum point contact is designed, which works as a trivial which-path detector whose efficiency can be simply tuned by a gate voltage.
Abstract: We present an experiment where we tune the decoherence in a quantum interferometer using one of the simplest objects available in the physics of quantum conductors: an Ohmic contact. For that purpose, we designed an electronic Mach-Zehnder interferometer which has one of its two arms connected to an Ohmic contact through a quantum point contact. At low temperature, we observe quantum interference patterns with a visibility up to 57%. Increasing the connection between one arm of the interferometer to the floating Ohmic contact, the voltage probe, reduces quantum interference as it probes the electron trajectory. This unique experimental realization of a voltage probe works as a trivial which-path detector whose efficiency can be simply tuned by a gate voltage.
TL;DR: The polarity switchability of generated UWB pulses is experimentally confirmed and the system is equivalent to a first- or second-order differentiator for the production of Gaussian UWB monocycle or doublet pulses.
Abstract: We propose a new scheme to generate polarity-switchable ultrawideband (UWB) Gaussian pulses in the optical domain by use of a phase modulator and a reconfigurable asymmetric Mach-Zehnder interferometer (AMZI). In the proposed system, an optical carrier is phase modulated by a Gaussian pulse train and then sent to a first-or second-order AMZI. The system is equivalent to a first- or second-order differentiator for the production of Gaussian UWB monocycle or doublet pulses. The polarity of the generated UWB pulses can be switched by adjusting the phase difference between the two interference components in the AMZI. An experiment is performed. Gaussian monocycle and doublet pulses with fractional bandwidths of about 177% and 140% are generated. The polarity switchability of generated UWB pulses is also experimentally confirmed.
TL;DR: A simple all-fiber structure based on intermodal interference between a core and a cladding mode of an endlessly single-mode photonic crystal fiber (PCF) section sandwiched between a lead-in and lead-out SMF-28 fiber was proposed in this paper.
Abstract: We propose a simple all-fiber structure based on intermodal interference between a core and a cladding mode of an endlessly single-mode photonic crystal fiber (PCF) section sandwiched between a lead-in and lead-out SMF-28 fiber. We have measured the intermodal dispersion and the polarization-dependent loss (PDL) of the structure. The sensitivities to strain, pressure, and temperature and external refractive index are studied. The interferometer is compared to an interferometer based on LP01-LP02 SMF-28 fiber and to a PCF-based tapered LPG.
TL;DR: In this article, a compact intrinsic fiber Mach-Zehnder interferometer (MZI) is proposed and experimentally demonstrated by incorporating a micro air-cavity ablated by femtosecond laser irradiation.
Abstract: A compact intrinsic fiber Mach-Zehnder interferometer (MZI) is proposed and experimentally demonstrated by incorporating a micro air-cavity ablated by femtosecond laser irradiation. A short cavity of length ~ 10 mum along the single-mode fiber core provided two optical paths: one propagating through the air and the other guided along the ring-shaped silica cladding. A spectral analysis confirmed MZI in a good agreement with experimental results. Temperature-dependent spectral shifts were measured and analyzed.
TL;DR: In this paper, a high-Q Mach-Zehnder interferometer (MZI)-coupled microring is presented for optical sensing with high sensitivity and a large measurement range.
Abstract: A high-Q Mach-Zehnder interferometer (MZI)-coupled microring is presented for optical sensing with high sensitivity and a large measurement range. By optimizing the length difference, between the t ...
TL;DR: The stabilized interferometer showed phase stability of 0.06 rad, which corresponds to an optical path length fluctuation of 15 nm between the 6-km-long interfering arms, and raw visibility obtained without subtracting noise counts in the single-photon interference experiment was more than 98% for stabilized conditions.
Abstract: We report on single-photon interference experiments in a Michelson-type interferometer built with two 6-km-long fiber spools, as well as on the active stabilization of the interferometer. A weak coherent light signal was (de-) multiplexed with a strong reference light using wavelength-division multiplexing technique, and real-time feedback control technique was applied for the reference light to actively stabilize the phase fluctuation in the long-armed fiber interferometer. The stabilized interferometer showed phase stability of 0.06 rad, which corresponds to an optical path length fluctuation of 15 nm between the 6-km-long interfering arms. The raw visibility obtained without subtracting noise counts in the single-photon interference experiment was more than 98% for stabilized conditions.
TL;DR: A high phase-shift efficiency Mach-Zehnder silicon optical modulator based on the carrier-depletion effect in a highly-doped PN diode with a small waveguide cross-sectional area is presented.
Abstract: We present a high phase-shift efficienct Mach-Zehnder silicon optical modulator based on the carrier-depletion effect in a highly-doped PN diode with a small waveguide cross-sectional area. The fabricated modulator show a VπLπ of 1.8V·cm and phase shifter loss of 4.4dB/mm. A device using a 750 μm-long phase-shifter exhibits an eye opening at 12.5Gbps with an extinction ratio of 3 dB. Also, an extinction ratio of 7 dB is achieved at 4 Gbps for a device with a 2 mm-long phase shifter. Further enhancement of the extinction ratio at higher operating speed can be achieved using a travelling-wave electrode design and the optimal doping.
20 Nov 2009
TL;DR: In this article, a beam splitter is proposed to realize a completely integrated Michelson interferometer, where a single medium interface (Si/Air) is used for optical beam splitting.
Abstract: A new beam splitter [1] is proposed to realize a completely integrated Michelson interferometer, where a single medium interface (Si/Air) is used for optical beam splitting. This offers a stable splitting ratio over a very wide spectral range. Using this technique on SOI wafers, with a moving mirror, a highly robust and tunable interferometer is fabricated. The tunable interferometer is tested experimentally by measuring optical interference versus mirror displacement.
TL;DR: By properly modulating the phase change in the ring waveguide, the shift of the resonant frequency and the asymmetry of the transmission spectra can be controlled to finally enable optical switching with a high extinction ratio, even complete extinction, in the ON state.
Abstract: A kind of Mach-Zehnder optical switch with a dual-bus coupled ring resonator as a two-beam interferometer is proposed and investigated. The analysis based on the transfer matrix method shows that a sharp asymmetric Fano line shape can be generated in the transmission spectra of such a configuration, which can be used to significantly reduce the phase change required for switching. Meanwhile, it can also be found that complete extinctions can be achieved in both switching states if the structural parameters are carefully chosen and the phase bias is properly set. Through tuning the phase difference between the arms of the Mach-Zehnder interferometer, complete extinction can be easily kept within a large range of the ring-bus coupling ratios in the OFF state. By properly modulating the phase change in the ring waveguide, the shift of the resonant frequency and the asymmetry of the transmission spectra can be controlled to finally enable optical switching with a high extinction ratio, even complete extinction, in the ON state. The switching functionality is verified by the finite-difference time-domain simulation.
TL;DR: A switchable multi-wavelength erbium-doped fiber ring laser based on a compact in-fiber Mach-Zehnder interferometer comb filter at room temperature is presented in this article.
Abstract: A switchable multi-wavelength erbium-doped fiber ring laser based on a compact in-fiber Mach–Zehnder interferometer comb filter at room temperature is presented. The comb filter is formed by splicing a section of twin-core fiber between two single mode fibers. By adjusting the states of the polarization controller appropriately, the laser can be made to operate in stable single-, dual- and three-wavelength lasing states. The operation principle is based on spectral hole burning induced by the saturated effect and polarization hole burning.
TL;DR: In this article, the visibility of Aharonov-Bohm oscillations as a function of voltage bias and express it via the cumulant generating function of noise was studied.
Abstract: We consider dephasing in the electronic Mach-Zehnder interferometer strongly coupled to current noise created by a voltage biased quantum point contact (QPC). We find the visibility of Aharonov-Bohm oscillations as a function of voltage bias and express it via the cumulant generating function of noise. In the large-bias regime, high-order cumulants of current add up to cancel the dilution effect of a QPC. This leads to an abrupt change in the dependence of the visibility on voltage bias which occurs at the QPC's transparency T=1/2. Quantum fluctuations in the vicinity of this point smear out the sharp transition.
TL;DR: In this paper, photon number resolving detectors were used to detect interference fringes with increasing photon numbers for a Fabry-Perot interferometer, which provided a higher precision in determining the position of the interference maxima compared to a classical detection strategy.
Abstract: With photon-number resolving detectors, we show compression of interference fringes with increasing photon numbers for a Fabry-Perot interferometer. This feature provides a higher precision in determining the position of the interference maxima compared to a classical detection strategy. We also theoretically show supersensitivity if $N$-photon states are sent into the interferometer and a photon-number resolving measurement is performed.
TL;DR: In this article, the authors derived the sensitivity and detection limit for Si-based sensors, which depends sensitively on the resonance shift of one of the microrings due to the presence of an analyte.
Abstract: Dual-microring-resonator interference with the microrings on separate arms of a Mach–Zehnder interferometer is shown to provide the basis for high-performance sensors. The output spectrum, which depends on the overlap of the resonances of the two microring resonators, depends sensitively on the resonance shift of one of the microrings due to the presence of an analyte. The sensitivity and detection limit are obtained theoretically and found to be as large as 0.31 nm overlap resonance shift according to 2×10−6 refractive index units for Si-based sensors.
Patent•
03 Nov 2009TL;DR: In this paper, an integrated control system for a laser and a Mach-Zehnder interferometer is described and configuring a bias point for low-speed control of an optical modulator utilizing control circuitry integrated on the same CMOS die.
Abstract: An integrated control system for a laser and Mach-Zehnder interferometer are disclosed and may include configuring a bias point for low-speed control of an optical modulator utilizing control circuitry integrated on the same CMOS die. The optical modulator may be differentially monitored. A laser source for the modulator may be controlled utilizing monitor photodiodes via optical taps on outputs of the modulator, or utilizing a monitor photodiode on one output port of the modulator, which may comprise a Mach-Zehnder interferometer. An error signal may be generated by subtracting monitor photodiode signals from optical taps on output ports of the modulator. The bias point of the modulator may be adjusted by minimizing the error signal. Calibration time of the bias point may be reduced utilizing electronic data inversion. An output of the modulator may comprise a Y-junction and a single monitor photodiode may measure both branches of the modulator.
TL;DR: A conservative estimate of the crosstalk ability of Mach-Zehnder optical switches is given, which shows that, while using a 1475 microm-long phase shifter, the loss penalty almost reaches 1.45 dB/pi, which deteriorates the most ideal crosStalk to just 30 dB.
Abstract: The free carrier absorption effect in silicon modulation is a detrimental behavior that can influence the crosstalk of interference-based optical switches. Based on the experimental analysis of a 2×2 p-i-n silicon switch, we give a conservative estimate of the crosstalk ability of Mach-Zehnder optical switches. Experimental result shows that, while using a 1475μm-long phase shifter, the loss penalty almost reaches 1.45dB/π, which deteriorates the most ideal crosstalk to just 30dB. The possible solutions to overcome this limitation are also discussed at the cost of the other device performance.