High Precision Repetition Rate stabilization

  • Ultra-low timing jitter
  • Hands-free operation
  • Maximum flexibility
  • Long term stability

Femtolock™ 2 is a sub-100 fs jitter synchronization unit for Element™ 2 and Synergy™ ultrafast Ti:Sapphire oscillators. It allows locking of the round-trip frequency of oscillator pulses to a given reference RF-source. The use of multiple harmonics of the resonator round-trip frequency in combination with a simple and passively stable femtosecond laser resonator (based on Dispersive Mirror technology) enables low jitter levels.*

Maximum Flexibility

Access to the loop filter settings allows the user to optimize the timing jitter and to adapt to different applications. Femtolock 2 enables synchronization of the laser’s repetition rate by locking on the fundamental input RF-frequency, on one of its higher harmonics or to easily switch between the two. Optionally, a dual piezo configuration provides precise synchronization by simultaneously locking on both fundamental and harmonic of the input RF-frequency. Femtolock 2 can be custom designed to meet your specific requirements in terms of frequency and configuration.


The system is based on a combination of fast piezo translator(s) (PZT) and a wide range translation stage. This arrangement allows the Femtolock 2 to compensate for fast fluctuations (kHz), as well as for slow or medium long term drifts (e.g. temperature drifts).  The unique configuration ensures resonance-free synchronization up to high frequencies and guarantees a long term drift-free operation.

* Adapted from G.M.H. Knippels et al. “Two color facility based on a broadly tunable free-electron laser and a sub-picosecond-synchronized 10-fs Ti:Sapphire laser” Optics Letters, Vol. 23, No. 22, Nov. 15, 1998.


Synchronization to clock signals
  Femtolock 2  
Output Characteristics  
Integrated Timing Jitter (1 Hz–1 MHz)2 <100 fs
RF Reference Input Requirements  
Frequency Range (nth harmonic of the repetition rate)3 350 MHz–1.5 GHz
Input Level @ 50 Ohm 7 dBm  
User Interface (W x D x H) 16.65 x 15.48 x 3.5 in (423 x 400 x 89 mm) (19" 2U standard)  
Actuator(L x W x H) 1.97 x 0.98 x 1.97 in (50 x 25 x 50 mm)  
Detector Head(L x W x H) 1.97 x 0.79 x 1.18 in (50 x 20 x 30 mm)  

1. Due to our continuous improvement program, specifications are subject to change without notice.
2. The jitter cannot be smaller than reference source. Specification applies to Element 2 and Synergy oscillators.
3. For synchronization to RF frequencies >1.5 GHz, please contact Spectra-Physics.

Femotlock 2 Dimensions

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Supporting Products

Product Description
Element 2
Ultrashort pulsed femtosecond oscillators
Ultra-broadband sub-10 fs Ti:Sapphire oscillator