Carrier Envelope Offset Frequency Detection Research Articles

Carrier envelope offset frequency detection and stabilization of a diode-pumped mode-locked Ti:sapphire laser.

We demonstrate the first diode-pumped Ti:sapphire laser frequency comb. It is pumped by two green laser diodes with a total pump power of 3 W. The Ti:sapphire laser generates 250 mW of average output power in 61-fs pulses at a repetition rate of 216 MHz. We generated an octave-spanning supercontinuum spectrum in a photonic-crystal fiber and detected the carrier envelope offset (CEO) frequency in a standard f-to-2f interferometer setup. We stabilized the CEO-frequency through direct current modulation of one of the green pump diodes with a feedback bandwidth of 55 kHz limited by the pump diode driver used in this experiment. We achieved a reduction of the CEO phase noise power spectral density by 140 dB at 1 Hz offset frequency. An advantage of diode pumping is the ability for high-bandwidth modulation of the pump power via direct current modulation. After this experiment, we studied the modulation capabilities and noise properties of green pump laser diodes with improved driver electronics. The current-to-output-power modulation transfer function shows a bandwidth larger than 1 MHz, which should be sufficient to fully exploit the modulation bandwidth of the Ti:sapphire gain for CEO stabilization in future experiments.

Detection of carrier-envelope offset frequency in an Er-doped fiber femtosecond laser

It is the inevitable trend of the development for the optical frequency comb based on the Ti: sapphire femtosecond laser to be replaced by that based on the Er: fiber femtosecond laser. The detection of the carrier-envelope offset f0 in the femtosecond laser is a key to the realization of an optical frequency comb. In this paper, the structure of the optical part of an Er: fiber optical frequency comb is introduced. The optical pulses from an Er: fiber femtosecond laser with a repetition of 230 MHz are first amplified with a two stage amplifiers, spectrally broadened in a highly nonlinear fiber, and then pass through a single-beam f—2f self-referencing interferometer. By optimizing the optical parameters, the f0 with a signal-to-noise ratio of 30 dB is obtained in the Er: fiber femtosecond laser, which is favorable for the realization of an Er: fiber frequency comb.

Self referenced Yb-fiber-laser frequency comb using a dispersion micromanaged tapered holey fiber

We demonstrate a fully stabilized frequency comb in the 1mum spectral region based on an Yb-fiber oscillator and a cladding pumped chirped pulse Yb-fiber amplifier whose output is spectrally broadened in a dispersion micromanaged holey fiber. The dispersion micromanaged fiber is used to generate efficient, low noise spectral components at 523nm which are heterodyned with the second harmonic of the amplifier output for standard f-to-2f self-referenced carrier envelope offset frequency detection. For comb stabilization we phase-lock this offset frequency and the oscillator repetition frequency simultaneously to an RF reference by feedback controlling the oscillator pump diode current and the driving voltage of an intracavity piezo-electric fiber stretcher respectively.