L. Krainer

Diode-pumped femtosecond Yb:KGd(WO 4 ) 2 laser with 1.1-W average power

We demonstrate what is to our knowledge the first mode-locked Yb:KGd(WO(4))(2) laser. Using a semiconductor saturable-absorber mirror for passive mode locking, we obtain pulses of 176-fs duration with an average power of 1.1 W and a peak power of 64 kW at a center wavelength of 1037 nm. We achieve pulses as short as 112 fs at a lower output power. The laser is based on a standard delta cavity and pumped by two high-brightness laser diodes, making the whole system very simple and compact. Tuning the laser by means of a knife-edge results in mode-locked pulses within a wavelength range from 1032 to 1054 nm. In cw operation, we achieve output powers as high as 1.3 W.

Compact Nd:YVO/sub 4/ lasers with pulse repetition rates up to 160 GHz

We present a comprehensive study on multigigahertz repetition rate Nd:YVO/sub 4/ lasers, passively mode-locked with semiconductor saturable absorber mirrors. A brief review of Q-switching instabilities with special emphasis on high repetition rate is given. We then present basic design guidelines, and experimentally show that one can push the pulse repetition rate of a Nd: YVO/sub 4/ laser up to 157 GHz, reaching the fundamental limit to the repetition rate which is given by the pulse duration and thus by the amplification bandwidth. We also demonstrate an air-cooled diode-pumped 10-GHz Nd: YVO/sub 4/ laser with 2.1-W average output power and 13% electrical-to-optical efficiency, showing the potential of solid-state lasers generating multiwatt, multigigahertz pulse trains with high efficiency.

Picosecond pulse sources with multi-GHz repetition rates and high output power

We review and compare several recently introduced approaches for the generation of picosecond pulse trains with multi-GHz repetition rates and relatively high average output power (up to several watts). Specifically, we consider passively mode-locked lasers with different gain media (Nd:YVO4, Er:Yb:glass, and surface-emitting semiconductor structures) as well as optical parametric oscillators.

Soliton mode-locked Er:Yb:glass laser

We report on a simple diode-pumped passively mode-locked Er:Yb:glass laser generating transform-limited 1536-nm solitons of 255-fs duration with a repetition rate of 50 MHz and average power of 58 mW. We also discuss timing jitter and the trade-off between short pulses and high output power in these lasers.

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.

Passively mode-locked picosecond lasers with up to 59 GHz repetition rate

We present very compact Nd:YVO4 lasers which are passively mode-locked with a semiconductor saturable absorber mirror at very high repetition rates between 39 and 59 GHz. We achieved between 30 and 80 mW of average output power and pulse durations of 4.8–5.5 ps. As the pulse-to-pulse spacing is only 17 ps at 59 GHz, we are approaching the limit in repetition rate which is set by the pulse duration.

Optical parametric oscillator with a 10-GHz repetition rate and 100-mW average output power in the spectral region near 1.5 µm

We demonstrate a synchronously pumped optical parametric oscillator that emits picosecond pulses at an ~1.55-mum wavelength with a repetition rate as a high as 10 GHz and as much as 100 mW of average power. It is pumped with a diode-pumped passively mode-locked 10-GHz Nd:YVO(4) laser. Because of its high repetition rate and its potential for ultrabroad tunability, this kind of system is useful for telecom applications. It should be scalable to 40 GHz and higher as required for future telecom networks.

Compact 10-GHz Nd:GdVO 4 laser with 0.5-W average output power and low timing jitter

We demonstrate a compact, diode-pumped Nd:GdVO4 laser with a repetition rate of 9.66 GHz and 0.5-W average output power. The laser is passively mode locked with a semiconductor saturable absorber mirror (SESAM), yielding 12-ps-long sech2-shaped pulses. For synchronization of the pulse train to an external reference clock, the SESAM is mounted on a piezoelectric transducer. With an electronic feedback loop of only a few kilohertz loop bandwidth we achieved a rms timing jitter of 146 fs (integrated from 10 Hz to 10 MHz). This is an upper limit because it is mostly limited by the measurement system. The laser setup with a simple linear cavity has a footprint of only 130 mm x 30 mm.

Diode-pumped passively mode-locked Nd:YVO/sub 4/ lasers with 40-GHz repetition rate

We present two different diode-pumped passively mode-locked Nd:YVO/sub 4/ lasers with a repetition rate of 40 GHz. This is the highest repetition rate demonstrated so far with diode-pumped 1-/spl mu/m solid-state lasers. The first laser design allows short pulses of 2.7-ps duration whereas the second laser design is optimized for high average output power of up to 288 mW. We compare both design approaches and show that there is a tradeoff between output power and pulse duration.

Passively mode-locked 1.3-/spl mu/m multi-GHz Nd:YVO/sub 4/ lasers with low timing jitter

We demonstrate diode-pumped passively mode-locked 1.34-/spl mu/m Nd:YVO/sub 4/ lasers with repetition rates of 5 and 10GHz. Passive mode locking is achieved by using a novel GaInNAs-based saturable absorber mirror. Phase noise measurements prove the low timing jitter that can be obtained with this kind of lasers.