We have characterized the reflectivity, modal discrimination, and passive mode locking performance of diode lasers with intracavity reflectors (ICR) composed of a different number of slots. Upon analysis, we demonstrate that a monolithic semiconductor mode-locked laser comprising a compound cavity formed by a single deeply etched ICR slot fabricated using the 1.55 μm AlGaInAs strained quantum-well material provides the best harmonic (M = 4) mode-locking performance, with Gaussian-pulses generated at a pulse repetition rate of 161.8 GHz and a pulse duration of 1.67 ps, providing a time-bandwidth product of 0.81.

We report a novel approach for increasing the output power in passively mode locked semiconductor lasers. Our approach uses epitaxial structures with an optical trap in the bottom cladding that enlarges the vertical mode size to scale the pulse saturation energy. With this approach we demonstrate a very high peak power of 9.8 W per facet, at a repetition rate of 6.8 GHz and with pulse duration of 0.71 ps. In particular, we compare two GaAs/AlGaAs epilayer designs, a double quantum well design operating at 830 nm and a single quantum well design operating at 795 nm, with vertical mode sizes of 0.5 and 0.75 μm, respectively. We show that a larger mode size not only shifts the mode locking regime of operation toward higher powers, but also produces other improvements with respect to two main failure mechanisms that limit the output power, catastrophic optical mirror damage and catastrophic optical saturable absorber damage. For the 830-nm material structure, we also investigate the effect of nonabsorbing mirrors on output power and mode locked operation of colliding pulse mode locked lasers.

High output power 40 GHz 1.55 μm passively mode-locked surface-etched distributed Bragg reflector (DBR) lasers with monolithically integrated semiconductor optical amplifiers are reported. These are based on an optimized AlGaInAs/InP epitaxial structure with a three quantum well active layer and an optical trap layer. The device produces near transform limited Gaussian pulses with a pulse duration of 3.3 ps. An average output power during mode-locked operation of 130 mW was achieved with a corresponding peak power of >1 W.

We report 40 GHz passively mode-locked 1.55 μm AlGaInAs/InP lasers with integrated tapered semiconductor optical amplifiers producing nearly transform limited pulses with a pulse width of 4.3 ps and average output power of 200 mW.

A novel laser structure design was used in passive mode-locking. Devices exhibited output with low divergence angle (12.7° × 26.3°), timing jitter of 194 fs (4-80 MHz), and RF linewidth of 2 kHz.

We demonstrate a high output power passively mode-locked distributed Bragg reflector laser with integrated tapered semiconductor optical amplifier, operating at 1.5 μm. These devices are based on an optimized low-optical-confinement AlGaInAs/InP epitaxial material with a three quantum wells active region and a passive far-field reduction layer. The device generates nearly transform-limited pulses with minimum pulse duration of 4.3 ps at 40-GHz repetition rate. An average output power of 200 mW with a corresponding output peak power of >;1.2 W is achieved.

We report femtosecond pulses from a passive C-band two-section AlGaInAs/InP mode-locked laser with a monolithically integrated passive waveguide made by quantum well intermixing. Without any external pulse compression, Lorentzian pulses are generated at a repetition frequency of ~38 GHz with 490 fs pulse duration, which is, to the best of our knowledge, the shortest pulse from any directly electrically pumped quantum well semiconductor mode-locked laser. The mode-locking range is relatively large and the ultranarrow pulse width is very stable over a broad range of driving conditions.

We report for the first time 490 fs pulse duration at a repetition frequency ~38 GHz from a passive C-band two-section AlGaInAs/InP mode-locked laser with a monolithically integrated passive waveguide made by quantum well intermixing.

We report on the detailed characterization of ultrashort pulses emitted from a 1.5-mu m AlGaInAs/InP semiconductor passively mode-locked laser, operating at a repetition frequency of 35 GHz. Both the temporal and phase profiles of the pulses are retrieved using a sonogram technique that utilizes a highly-sensitive two-photon absorption waveguide detector. The system enables full characterization of pulses with energy as low as 10 fJ and peak power level of 5 mW, which is only inaccessible by a limited number of high-sensitivity measurement approaches. We show that the pulses exhibit a prevailing positive linear chirp across a wide range of biasing conditions. Its high sensitivity to the gain section current proves the dominant contribution of the gain conditions to the group delay characteristics of the emitted pulses.

A monolithic ~1.55-μm colliding-pulse mode-locked AlGaInAs/InP laser with a three-quantum-well active layer incorporating a passive far-held reduction layer has been demonstrated. The device emits pulses at 162 GHz, with a pulsewidth of 0.98 ps, a pulse energy of 0.13 pJ, and a time-bandwidth product of 0.52, while demonstrating a low divergence angle (12.7° × 26.3°) with a twofold improvement in butt coupling efficiency to a flat cleaved single-mode fiber, compared to the conventional mode-locked lasers.

A novel 40 GHz passively mode-locked AlGaInAs/ InP 1.55 mu m laser was demonstrated with low divergence angle (12.7 degrees x 26.3 degrees), timing jitter of 440 fs (100 Hz - 100 MHz), and RF linewidth of 25 kHz. (C)2011 Optical Society of America

A novel 20 GHz 1.55 μm passively colliding-pulse mode-locked AlGaInAs/InP laser was demonstrated with a small RF linewidth (10 kHz), low timing jitter of 218 fs (4-80 MHz) and low divergence angle (14.7° × 27.3°).

The monolithic integration of four 1.50-μm range AlGaInAs/InP distributed feed-back lasers with a 4 × 1 multimode-interference optical combiner, a curved semiconductor optical amplifier and an electroabsorption modulator using relatively simple technologies-sidewall grating and quantum well intermixing-has been demonstrated. The four channels span the wavelength range of 1530-1566 nm and can operate separately or simultaneously. The epitaxial structure was designed to produce a far field pattern at the output waveguide facet, which is as small as 21.2°× 25.1°, producing a coupling efficiency with an angled-end single mode fiber at twice that of a conventional device design.

In this paper we report a new epitaxial laser wafer design and the performance of an 80-GHz AlGalnAs/InP λ~l .55 μm CPM laser with a low divergence angle and timing jitter. Based on a standard epi-wafer, an additional thin layer (160-nm-thick 1.1Q), hereafter referred to as the far-field reduction layer (FRL), was inserted in the lower n-cladding layer with a 750-nm-thick InP spacer between the active layer and FRL. This design increases the spot size and reduces the internal loss of the cavity, while suppressing higher transverse mode lasing.