Optical Frequency Combs
Jun 2015TOPTICA Photonics Inc.Request Info
VICTOR, N.Y. — New offset-free optical frequency combs from Toptica Photonics Inc. enable unprecedented passive stability for complex experiments.
The difference frequency comb (DFC) operates with Cero technology (zero-νCEO), which obtains a phase-stable laser output with an inherently vanishing frequency offset. To achieve this, femtosecond laser pulses centered at 1560 nm are generated with a mode-locked Er3+-doped fiber oscillator. Subsequent amplification and coherent spectral broadening of the pulses in a nonlinear fiber creates a broad supercontinuum.
Difference frequency generation (DFG) between the lower and upper spectral parts of the supercontinuum produces a frequency comb output centered at 1560 nm. Since the two spectral parts have identical carrier-envelope frequencies, the resulting comb is offset-free, due to common-mode suppression in the DFG process. In other words, the carrier-envelope frequency is fixed at zero automatically, and no active stabilization of the phase is necessary.
This passive approach results in improved phase stability and higher reliability compared with conventional active stabilization techniques. The absence of an electronic feedback loop for phase stabilization leads to reduced system complexity and circumvents electronic noise limitations.
The system comes with an integrated radio frequency reference and locking electronics to synchronize the repetition rate, or it can be locked to an optical reference.
The main unit, DFC-Core, provides four νCEO-stabilized outputs at 1560 nm. Various extensions are available to convert the outputs to any desired wavelength from 420 to 2200 nm. All CW lasers in this wavelength range can be locked to the frequency comb.