Time-lenses were developed rapidly over the last year. They enable measurements of ultrafast signals which were not measured before with limited electronics detectors. Time-lens enable to image ultrafast signals from sub picosecond time-scales to nanosecond time-scale while preserving the intensity, phase and state of polarization. However, most time-lenses are focus only on the time-domain and ignore the spatial domain. This hinder many ultrafast phenomena which combine the dynamics in time and space together. In this proceeding, we demonstrate the measured results of the mode splitter which is a crucial device for achieving a time-lens which combines time and space.
Temporal imaging system have enabled imaging of ultrafast phenomena with high temporal resolution different ultrafast phenomena. Specifically, time-lenses which are based on nonlinear interaction of four-wave mixing have a wide field of view together with high F-number. These offers temporal imaging system with large magnifications in the time-domain. However, when considering a time-lens based on four-wave mixing interaction, the input signal must be synchronized to the pump wave which makes it challenging for measuring any ultrafast phenomena with unknown time-of-arrival. Therefore, we developed a temporal imaging system which does not require this synchronization between a signal and a pump wave. This is done by generating time-lenses with high repetition-rate. Therefore, any input signal will interact with one of the time-lenses and it will be imaged in time with high probability. In this proceeding, we demonstrate how our temporal scheme is able to measure with high temporal resolution the start-up dynamics of pulsation in a fiber laser.
Time-lenses in general proved to be useful for many applications and specifically when utilizing them for temporal imaging schemes where they can image ultrafast signals that cannot be detected by any electronic based device. Over the last few years, we demonstrated that when joining together several time-lenses into a single time-lens array, it is possible to gain more information on the input signal. Such as measuring temporal depth imaging, the state of polarization of the input signal as a function of time, and retrieving the phase dynamics. However, when designing an array of time-lenses, there is a trade-off between joining large number of small time-lenses, so each signal will interact with many time-lenses but each one has low resolution, and joining small number of large time-lenses, so each has better temporal resolution but on the expanse of interacting with smaller number of time-lenses in the array. We showed that one way to overcome this drawback is to overlap adjacent timelenses. Thus it is possible to both have large number of time-lenses without compromising on the size of each time-lens and obtaining high temporal resolution. In this proceeding, we overlap two time-lenses and measure the spectrum of the idler. We compare the numerical simulations of the frequency domain of the idler to the measured spectrum of the idler.
Time-lenses were developed rapidly over the last year. They enable measurements of ultrafast signals which were not measured before with limited electronics detectors. Time-lens enable to image ultrafast signals from sub picosecond time-scales to nanosecond time-scale while preserving the intensity, phase and state of polarization. However, most time-lenses are focus only on the time-domain and ignore the spatial domain. This hinder many ultrafast phenomena which combine the dynamics in time and space together. In this proceeding, we demonstrate the measured results of the mode splitter which is a crucial device for achieving a time-lens which combines time and space.
Temporal imaging system have enabled imaging of ultrafast phenomena with high temporal resolution different ultrafast phenomena. Specifically, time-lenses which are based on nonlinear interaction of four-wave mixing have a wide field of view together with high F-number. These offers temporal imaging system with large magnifications in the time-domain. However, when considering a time-lens based on four-wave mixing interaction, the input signal must be synchronized to the pump wave which makes it challenging for measuring any ultrafast phenomena with unknown time-of-arrival. Therefore, we developed a temporal imaging system which does not require this synchronization between a signal and a pump wave. This is done by generating time-lenses with high repetitionrate. Therefore, any input signal will interact with one of the time-lenses and it will be imaged in time with high probability. In this proceeding, we demonstrate how our temporal scheme is able to measure with high temporal resolution the start-up dynamics of pulsation in a fiber laser.
A time-lens can image signals in time and map ultrafast signals from frequency to time. The concept of time-lens is based on the duality between the diffraction of light in space and the dispersion of pulses in time, which arises from the similarity between the equations describing these two phenomena. In this paper we explain how to use time-lenses in order to perform high-resolution temporal imaging on non-classical ultrafast signals. Such a scheme can be used e.g. for diagnosing quantum cryptography schemes on optical fiber networks or assessing the performance of photonic quantum computers and simulators.
We developed a unique temporal imaging scheme which is able to detect all the properties of an optical signal in a sub picosecond resolution. This includes imaging of the intensity, the phase, and the state of polarization as a function of time. We are aiming to utilize this advance temporal imaging scheme for studying ultrafast phenomena which were not investigated until now. In this proceeding we describe in details the experimental setup with all its components and parts beyond what we showed and explained in the paper.
Time-lenses in general proved to be useful for many applications and specifically when utilizing them for temporal imaging schemes where they can image ultrafast signals that cannot be detected by any electronic based device. Over the last few years, we demonstrated that when joining together several time-lenses into a single time-lens array, it is possible to gain more information on the input signal. Such as measuring temporal depth imaging, the state of polarization of the input signal as a function of time, and retrieving the phase dynamics. However, when designing an array of time-lenses, there is a trade-off between joining large number of small time-lenses, so each signal will interact with many time-lenses but each one has low resolution, and joining small number of large time-lenses, so each has better temporal resolution but on the expanse of interacting with smaller number of time-lenses in the array. We showed that one way to overcome this drawback is to overlap adjacent timelenses. Thus it is possible to both have large number of time-lenses without compromising on the size of each time-lens and obtaining high temporal resolution. In this proceeding, we overlap two time-lenses and measure the spectrum of the idler. We compare the numerical simulations of the frequency domain of the idler to the measured spectrum of the idler.
We developed a time lens which is able to measure the full state of polarization as a function of time for single shot input signals. This is done by splitting the input signal into three copies and projecting each one on a different Stoke vector. In this proceeding, we present the experimental setup in details for measuring the different Stokes vectors.
Over the last years, we developed advanced microfiber devices including fiber microknots and long period fiber gratings on tapered fibers. In this proceeding, we present our try out to create a twisted fiber for manipulating the state of polarization of the light and specifically to rotate the state of polarization. This attempt did not succeed due to the fact that we tapered the fiber during the twisting by heating it which relieved all the tension in the fiber and prevented from creating twisted birefringence.
We developed novel fiber microknots which are designed for high order mode beams traveling in the fiber. The device is based on long period fiber gratings which excite high order modes in tapered fiber and a microknot which is fabricated on the tapered fiber. Thus, the light that resonates in the microknot is propagating in the tapered fiber in high order modes which have higher coupling to the environment. The light which exits the microknot and continue to propagate in the fiber is then exited back to the Gaussian mode by another long period fiber grating before the fiber returns to be a single mode fiber. We found that the spectral response of these microknots have deeper resonances and improved Q-factor.
We investigated the spectral response of complex fiber micro-knots. We found reach spectral response for both transmitted and reflected light from these complex micro-knots. We analyzed these complex micro-knots and found good agreement between the calculated and the measured results.
We developed temporal super-resolution technique by adopting super-resolution techniques from space to time. Similar to spatial optics, where knowledge about the basic building blocks of the image can lead to better resolution, as demonstrated by localization microscopy techniques. We are utilizing our knowledge on the shape and duration of the pulses to retrieve a super-resolution image in the time domain of an input signal. The resolution of our time-lens is much lower than the needed resolution to obtain the signal but never-the-less we obtain a temporal image with high resolution.
We developed the concept of temporal depth imaging and defined non-flat signals as signals with different dispersion values as a function of time. We demonstrated how shifting the timing of a time lens makes it possible to retrieve the dispersion value of each point in the signal, which is equivalent to a 3D imaging system. Finally, we demonstrated how a time lens array can retrieve these values with a single measurement by comparing the different images obtained by the time lens array.
We investigated ultrafast rogue waves in fiber lasers and found three different patterns of rogue waves: single- peaks, twin-peaks, and triple-peaks. The statistics of the different patterns as a function of the pump power of the laser reveals that the probability for all rogue waves patterns increase close to the laser threshold. We developed a numerical model which prove that the ultrafast rogue waves patterns result from both the polarization mode dispersion in the fiber and the non-instantaneous nature of the saturable absorber. This discovery reveals that there are three different types of rogue waves in fiber lasers: slow, fast, and ultrafast, which relate to three different time-scales and are governed by three different sets of equations: the laser rate equations, the nonlinear Schrodinger equation, and the saturable absorber equations, accordingly. This discovery is highly important for analyzing rogue waves and other extreme events in fiber lasers and can lead to realizing types of rogue waves which were not possible so far such as triangular rogue waves.
Modern networks implement multi-layer encryption architecture to increase network security, stability, and robustness. We developed a new paradigm for optical encryption based on the strengths of optics over electronics and according to temporal optics principles. We developed a highly efficient all-optical encryption scheme for modern networks. Our temporal encryption scheme exploits the strength of optics over electronics. Specifically, we utilize dispersion together with nonlinear interaction for mixing neighboring bits with a private key. Our system encrypts the entire network traffic without any latency, encrypt the signal itself, exploit only one non- linear interaction, it is energetically efficient with low ecologic footprint, and can be added to current networks without replacing the hardware such as the lasers, the transmitters, the routers, the amplifiers or the receivers. Our method can replace current slow encryption methods or can be added to increase the security of existing systems. In this paper, we elaborate on the theoretical models of the system and how we evaluate the encryption strength with this numerical tools.
We present long period fiber gratings which are constructed of periodic changes in the fiber diameter. Our long period fiber gratings induce strong coupling between the different modes and as such have wider bandwidth and even off-resonance spectral response. We present both calculated and measured results of these long period fiber gratings.
We present fusing of fiber micro-knot by CO2 laser which fixes the micro-fibers in place and stabilizing the micro-knot shape, size and orientation. This fusing enables tuning of the coupling strength, the free-spectral range and the birefringence of the fiber micro-knot. Fused micro-knots are superior over regular micro-knots and we believe that fusing of micro-knots should be a standard procedure in fabricating fiber micro-knots.
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