Adrian Schlatter

Solid-state Er:Yb:glass laser mode-locked by using single-wall carbon nanotube thin film

We design single-wall carbon nanotube (SWNT) thin-film saturable absorbers (SAs) integrated onto semiconductor distributed Bragg reflectors for mode-locking solid-state Er:Yb:glass lasers. We characterize the low nonsaturable loss, high-damage-threshold SWNT SAs and verify their operation up to a pulse fluence of 2 mJ/cm(2). We demonstrate passive fundamental continuous-wave mode locking with and without group-delay dispersion compensation. Without compensation the laser produces chirped 1.8 ps pulses with a spectral width of 3.8 nm. With compensation, we obtain 261 fs Fourier-transform-limited pulses with a spectral width of 9.6 nm.

Nearly quantum-noise-limited timing jitter from miniature Er:Yb:glass lasers.

We havemeasured therelative timing jitter oftwopassively mode-locked 10-GHz Er:Yb:glass lasers tobe190fs(100Hz-1.56 MHz)infree-running and26fs(6Hz-1.56 MHz) insynchronized operation. Wepresent theresults oftiming jitter measurements fortwopassively mode-locked 10-GHzEr:Yb:glass lasers (Time- Bandwidth Products ERGO PGL).Thecavities arebuilt withgreat careformechanical stability andadditionally enclosed inametal case.Thelasers produce ;15mW ofaverage output power(fiber coupled) in1.5-ps Gaussian pulses. Thetiming ofthepulses relative tothat ofanexternal reference oscillator canbestabilized withaphase-locked loop which controls thecavity length bymoving anendmirror mounted onapiezo actuator. Tomeasure therelative timing jitter ofthetwolasers, weuseanindirect phase comparison method(l) that allows precise jitter measurements forfree-running ortiming-stabilized mode-locked lasers. Thefigure shows measured two- sided timing phase noise powerspectra ofthefree-running andthetiming-stabilized lasers. Eachcurve represents the average offoursingle measurements with ameasurement timeof0.17s.Thedashed line showsthelimit given by quantum noise sources inthecavities.(2)

Pulse-energy dynamics of passively mode-locked solid-state lasers above the Q-switching threshold

We have investigated the dynamical behavior of various passively mode-locked solid-state lasers by measuring how a modulation of the pump power affects the output power. We show theoretically and experimentally how the damping of the relaxation oscillations is reduced and finally becomes zero when the pump power is reduced so that the threshold for Q-switched mode locking is approached. For the first time to our knowledge, this method provides important information on the stability of mode locking above the Q-switched mode-locking threshold. It is applicable to lasers that are mode locked with slow-saturable absorbers. The results helped to explain the cause of unexpectedly low Q-switching thresholds in two cases. Also we obtain some useful spectroscopic information.

Passively mode-locked 914-nm Nd:YVO4 laser

We demonstrate what is to our knowledge the first mode-locked Nd:YVO4 laser operating on the 4F3/2-4I9/2 transition at 914 nm. Using a semiconductor saturable-absorber mirror for passive mode locking, we have obtained 3-ps pulses at a repetition rate of 233.8 MHz. The laser is based on a standard delta cavity and is pumped by a Ti:sapphire laser. We obtained an average output power of 42 mW through one mirror and an accumulated output power of approximately 150 mW (through all cavity mirrors) at a pump power of 1.4 W.

Compact Er:Yb:glass-laser-based supercontinuum source for high-resolution optical coherence tomography

We present a low coherence light source by direct super-continuum generation from a diode-pumped, passively modelocked Er:Yb:glass-laser, which generates 198 fs transform-limited pulses with an average power of 100 mW at a repetition rate of 75 MHz. The pulse train is launched into a dispersion optimized highly nonlinear fiber for spectral broadening. The optical bandwidth spans from 1150 nm to 2400 nm, which is more than one octave. The potential for ultrahigh-resolution optical coherence tomography (OCT) is demonstrated by coherence measurements supporting an axial resolution of 3.5 microm in air.

Nearly quantum noise limited timing jitter from miniature Er:Yb:glass lasers

We have measured the relative timing jitter of two passively mode-locked 10-GHz Er:Yb:glass lasers to be 190 fs (100 Hz-1.56 MHz) in free-running and 26 fs (6 Hz-1.56 MHz) in synchronized operation.

Fiber-Broadened Passively Modelocked Er: Yb: Glass Laser for High-Resolution Optical Coherence Tomography

We demonstrate a low coherence light source by directly launching the output of a femtosecond diode-pumped modelocked Er:Yb:glass laser into a highly-nonlinear fiber. The measured interferogram supports a depth resolution of 4 mum in air.

Octave spanning supercontinuum from compact passively mode-locked Er:Yb:glass laser

By using a recently developed nonlinear fiber, we achieve octave-spanning spectrum directly from a diode-pumped passively mode-locked 250-fs Er:Yb:glass laser without any amplification stage. Applications for CEO phase stabilization and optical clocking are discussed.

Pulse energy dynamics of passively mode-locked solid-state lasers above the Q-switching threshold

We have investigated the dynamical behavior of various passively mode-locked solid-state lasers by measuring how a modulation of the pump power affects the output power. We show theoretically and experimentally how the damping of the relaxation oscillations is reduced and finally becomes zero when the pump power is reduced so that the threshold for Q-switched mode locking is approached. For the first time to our knowledge, this method provides important information on the stability of mode locking above the Q-switched mode-locking threshold. It is applicable to lasers that are mode locked with slow-saturable absorbers. The results helped to explain the cause of unexpectedly low Q-switching thresholds in two cases. Also we obtain some useful spectroscopic information.

Simultaneous measurement of the optical phase noise of all modes of a mode-locked laser

We present a method to measure the phase fluctuations of all modes of a mode-locked laser simultaneously and time resolved. With this method we characterized the noise of 5-GHz 1.3-mum Nd:YVO4 lasers.