We report on the first demonstration of a passively mode-locked, diode-pumped, monolithic Yb:glass channel waveguide laser that incorporates a semiconductor saturable absorber mirror. Stable and self-starting mode-locking is achieved in a Fabry-Perot cavity configuration producing a pulse repetition rate up to 4.9 GHz. The shortest pulse duration of 740 fs is generated with 30 mW of average output power at a center wavelength of 1058 nm. A maximum output power of 81 mW is produced during mode-locking with corresponding pulse duration of 800 fs. © 2012 Optical Society of America OCIS codes: 140.4050, 140.7090, 140.3615, 230.7380, 320.7080. The development of ultrashort pulse lasers operating at pulse repetition rates in the gigahertz regime is of particular interest for applications in frequency comb metrology [1], optical communications [2], biophotonics [3] and ultrafast optical sampling [4], and a wide range of semiconductor, fiber and solid-state mode-locked lasers have been developed for these purposes. Monolithically integrated edge-emitting or vertical external cavity surface emitting semiconductor lasers are attractive options to produce femtosecond pulses with multigigahertz pulse repetition frequencies [5][6][7]. However, due to the presence of fast gain dynamics during mode-locking, ultrafast semiconductor lasers, in general, are characterized by high timing jitter of hundreds of femtoseconds [8]. Also, the generated average powers are rather limited apart from a few demonstrations where a high-power operation was achieved at low temperatures of a gain chip [7,9]. To develop fiber-based high repetition rate oscillators, a harmonic modelocking technique [10] is generally used which, however, tends to be less stable than fundamental mode-locking. More recently, Fabry-Pérot high-gain Er-doped ultrafast fiber lasers, that were passively mode-locked by a carbon nanotubes saturable absorber or a saturable Bragg reflector, were demonstrated [11][12][13] where fundamental repetition rates up to 19 GHz were realized (∼1 mW average power in the picosecond regime) [12] and a maximum average output power above 50 mW was produced with ∼206 fs pulses at 3 GHz pulse repetition rate [13]. The Fabry-Pérot cavity approach, in combination with solid-state waveguide-based gain media, enables further progress towards the development of more efficient, less expensive, and stable ultrafast and ultrahigh repetition rate laser systems that would offer an integrable status. Diode-pumped solid-state lasers (DPSSL) are excellent candidates for the development of multi-gigahertz repetition rate femtosecond systems because they combine favorable performance characteristics such as low threshold and high efficiency and low intrinsic quantum noise under the operational conditions afforded by costeffective and compact diode-pumping. Several demonstrations of femtosecond DPSSLs, operating at repetition rates above 1 GHz, have been reported [14][15][16] where the highest repetition frequency of 4.8 GHz was produced by a Yb:KGdW lase...
