Browsing by Author "Winter, A."

Now showing 1 - 5 of 5

Open Access
Femtosecond Yb-doped fiber laser system at 1 μm of wavelength with 100-nm bandwidth and variable pulse structure for accelerator diagnostics
(2007-05) Winter, A.; İlday, F. Ömer; Steffen, B.
Laser-based diagnostic systems play an increasingly important role in accelerator diagnostics in, for instance, electron bunch length measurements. To date, the laser system of choice for electro-optic experiments has been the Ti:sapphire laser, providing several nanojoules of pulse energies at fixed a repetition rate, which is not well suited to the bunch structure of accelerator facilities such as FLASH. Limited long-term stability and operability of Ti:sapphire systems are significant drawbacks for a continuously running measurement system requiring minimal maintenance and maximum uptime. We propose fiber lasers as a promising alternative with significant advantages. Gating of the pulse train to match the bunch profile is simple with fibercoupled modulators, in contrast to bulk modulators needed for Ti:sapphire lasers. An in-line fiber amplifier can boost the power, such that a constant pulse energy is maintained regardless of the chosen pulse pattern. Significantly, these lasers offer excellent robustness at a fraction of the cost of a Ti:sapphire laser and occupy a fraction of the optical table space.
Open Access
High-precision laser master oscillators for optical timing distribution systems in future light sources
(European Physical Society Accelerator Group (EPS-AG), 2006) Winter, A.; Schmüser, P.; Ludwig, F.; Schlarb, H.; Chen, J.; Kärtner, F. X.; ilday, F. ÖMER
An ultra-stable timing and synchronization system for linac-driven FELs has been designed providing 10 fs precision over distances of several kilometers. Mode-locked fiber lasers serve as master oscillators. The optical pulse train is distributed through length-stabilized fiber links. The layout of the optical synchronization system and its phase noise properties are described. A prototype system has been tested in an accelerator environment and has achieved the required stability.
Open Access
An integrated femtosecond timing distribution system for XFELS
(Massachusetts Institute of Technology, 2006) Kim, J.; Burnham, J.; Chen, J.; Kartner, F. X.; İlday, Fatih Ömer; Ludwig, F.; Schlarb, H.; Winter, A.; Ferianis, M.; Cheever, D.
Tightly synchronized lasers and RF-systems with timing jitter in the few femtoseconds range are necessary sub-systems for future X-ray free electron laser facilities. In this paper, we present an optical-microwave phase detector that is capable of extracting an RF-signal from an optical pulse stream without amplitude-to-phase conversion. Extraction of a microwave signal with 3 fs timing jitter (from 1 Hz to 10 MHz) from an optical pulse stream is demonstrated. Scaling of this component to subfemtosecond resolution is discussed. Together with low noise mode-locked lasers, timing-stabilized optical fiber links and compact optical cross-correlators, a flexible femtosecond timing distribution system with potentially sub-10 fs precision over distances of a few kilometers can be constructed. Experimental results on both synchronized RF and laser sources will be presented.
Open Access
Pulse shaping for a long-distance optical synchronization system
(Denshi Jouhou Tsuushin Gakkai, Institute of Electronics Information and Communication Engineer, 2007) Ilday, F. O.; Winter, A.; Kärtner, F. X.; Danailov, M. B.
Next generation free electron lasers aim to generate x-ray pulses with pulse durations down to 30 fs, and possibly even sub-fs. Synchronization of various stages of the accelerator and the probe laser system to the x-ray pulses with stability on the order of the pulse width is necessary to make maximal use of this capability. We are developing an optical timing synchronization system in order to meet this challenge. The scheme is based on generating a train of short optical pulses, with a precise repetition frequency, from a mode-locked laser oscillator and distributed via length-stabilized optical fibers to points requiring synchronization. The timing information is embedded in the repetition frequency and its harmonics. A significant advantage of the optical synchronization system is that multiple mode-locked Ti:sapphire seed oscillators typically present in an accelerator facility can be replaced by the master mode-locked fiber laser. In this paper, we briefly review progress on the development of the synchronization system and then discuss the implementation of this new possibility. Several technical issues related to this approach are analyzed.
Open Access
Ultra-low timing-jitter passively mode-locked fiber lasers for long-distance timing synchronization
(SPIE, 2006) İlday, F. Ömer; Winter, A.; Kim J.-W.; Chen, J.; Schmüser, P.; Schlarb, H.; Kärtner, F. X.
One of the key challenges for the next-generation light sources such as X-FELs is to implement a timing stabilization and distribution system to enable ∼ 10 fs synchronization of the different RF and laser sources distributed in such facilities with distances up to a few kilometers. These requirements appear to be beyond the capability of traditional RF distribution systems based on temperature-stabilized coaxial cables. A promising alternative is to use an optical transmission system: A train of pulses generated from a laser with low timing jitter is distributed over length-stabilized fiber links to remote locations. The repetition frequency of the pulse train and its higher harmonics contain the synchronization information. At the remote locations, RF signals are extracted simply by using a photodiode and a suitable bandpass filter to pick the desired harmonic of the laser repetition rate. Passively mode-locked Er-doped fiber lasers provide excellent long-term stability. The laser must have extremely low timing jitter, particularly at high frequencies (>1 kHz). Ultimately, the timing jitter is limited by quantum fluctuations in the number of photons making up the pulse and the incoherent photons added in the cavity due to spontaneous emission. The amplitude and phase noise of a home-built laser, generating 100-fs, 1-nJ pulses, was characterized. The measured phase noise (timing jitter) is sub-10 fs. from 1 kHz to Nyquist frequency. In addition to synchronization of accelerators, the ultra-low timing jitter pulse source can find applications in next-generation telecommunication systems.