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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 investigated the vectorial nature of ultrafast rogue waves in fiber lasers. In this proceeding, we present the analytical evolution of the nonlinear Schroedinger equation in vector field and show that when considering two Solitons with different state of polarization, they do not stay static which indicates that such Solitons are not a solution of the system.

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.

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.

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.

Phase retrieval is an important field in communication systems, since detectors are generally able to measure intensity while the phase is lost. One of the most common phase retrieval methods is the Gerchberg-Saxton (GS). This algorithm uses two intensity images, while imposing the amplitudes known from the intensities and keeping the phase, the algorithm iteratively reconstructs the lost phase. It was demonstrated that by adding more intensity images, one increase the probability to converge to the correct reconstruction. Space time duality states that since spatial diffraction and temporal dispersion are described by similar equations, the same methodologies developed in space are applicable in time. Following this principle, temporal lenses where developed. Since temporal imaging systems suffer from the same phase loss, phase retrieval methods were applied in this field as well. However, as in space, accurate phase retrieval requires multiple intensity images. In this work, we propose a temporal phase retrieval methods based on Gerchberg-Saxton, where the multiple planes are measured by a timelens array. The temporal lens array is achieved using four-wave mixing interaction between a signal and a chirped pump wave, resulting in high temporal magnification. The proposed iterative phase reconstruction algorithm takes advantage of the overlap between nearby lenses, which improves the convergence. We demonstrate how increasing the number of planes improves the reconstruction. Furthermore, the use of shifted lenses, as opposed to several defocused images, has a practical advantage in regards to additional errors in the system.

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.

In this proceeding, we describe in details our experimental setup and the free-space scheme which enable us to develop advanced time-lenses. We compare different methods for preparing the pump pulses and explain their pros and cons. Specifically, we show that when assembling the time-lens in free space, the system has lower losses which result in higher efficiency and thus less amplifiers. Since we do not need as many amplifiers, the noise level is lower and we can detect weaker signals.

Fiber micro-knots are a promising and a cheap solution for advanced fiber-based sensors. We investigated complex fiber micro-knots in theory and experiment. We compared the measured spectral response and present an analytical study of simple micro-knots with double twists, twin micro-knots, figure-eight micro-knots, and tangled micro-knots. This research brings the simple fabrication process and robustness of fiber micro-knots into the world of complex resonators which may lead to novel optical devices based on fiber micro-knots.

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.

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 developed a unique time-lens configuration for measuring in real time the temporal evolution of Rogue waves in optical fibers. Our time-lens configuration is based on array of several time-lens and we obtain the temporal evolution of Rogue waves by super-resolution techniques similar to a 3D imaging by a lens array. The experimental and calculated results as well as the theoretical background will be presented.

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.

Selections from our recent developments in passive phase locking and coherent combining of lasers are presented. These include the principles of our approaches, lasers configurations, experimental procedures and results with solid state lasers and fiber lasers.