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We review the main results obtained with our recently introduced passively fundamental mode-locked Er:Yb:glass lasers mainly in the context of telecom applications, and we discuss their key enablers. Specifically, we focus on the aspects of the lasers for application in the time-domain for optical time-division multiplexing and in the wavelength domain for dense wavelength-division-multiplexing.

In this paper, a technology comparison between monolithic passively mode-locked lasers (MLLs) fabricated from 1.24 μm InAs dots-in-a-Well (DWELL) and 1.25 μm InGaAs single quantum well (SQW) structures grown using elemental source molecular beam epitaxy (MBE) is presented. 5 GHz optical pulses with sub-picosecond RMS jitter, high pulse peak power (1W) and narrow pulse width (< 10 ps) are typical of these monolithic two-section InAs DWELL passive MLLs. An InGaAs single quantum well MLL with the 42% indium is shown to exhibit a superior high-temperature performance. Compared with the typical operating range of the InAs DWELL devices (<60°C), the operation is in excess of 100 °C and is particularly attractive for clocking applications in next generation microprocessors. Based on an 8-band k.p analysis the reduction in the band edge density of states for such a quantum well is discussed.

A novel type of a saturable absorber for passive mode locking was proposed. As the novel saturable absorber, we studied the thin solid films of the molecular J-aggregates of polymethyn dyes. The films of the J-aggregates were prepared using different polymethyn dyes. Linear and nonlinear optical properties of these films were investigated. Passive mode locking using these films as the saturable absorber was performed in a Nd³⁺:YAG laser. Stable generation of short pulses (pulse duration 13 ps) was achieved.

Erbium-doped unidirectional fiber ring laser has been passively mode-locked with a novel ultra-fast semiconductor saturable absorber used in transmission. The structure is based on InGaAs/InP multiple quantum wells grown on an InP substrate. Different structures with recovery time down to picosecond have been tested. Relaxation time reduction have been obtained by iron doping. With such structures, detrimental regimes such as Q-switch and Q-switch/ModeLock regimes have been avoided. Solitonic and slightly stretched-pulse dispersion regimes have been tested. The laser delivers for both, completely self-starting picosecond pulses of 8 mW maximum average output power at a repetition rate around 25 MHz.

We review the main results obtained with our recently introduced passively fundamental mode-locked Er:Yb:glass lasers mainly in the context of telecom applications, and we discuss their key enablers. Specifically, we focus on the aspects of the lasers for application in the time-domain for optical time-division multiplexing and in the wavelength domain for dense wavelength-division-multiplexing.