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We have developed an InAs/InP quantum dot (QD) gain material using a double cap growth procedure and GaP sublayer to tune QDs into the L-band. By using it, a passive L-band mode-locked laser with pulse duration of 445 fs at the repetition rate of 46 GHz was demonstrated. The 3-dB linewidth of the RF spectrum is less than 100 KHz. The lasing threshold injection current is 24 mA with an external differential quantum efficiency of 22% and an average output power of 27 mW. The relationship between pulse duration and 3-dB spectral bandwidth as a function of injection current was investigated.

A 93-channel multiwavelength laser with maximum channel intensity non-uniformity of 3.0 dB over a wavelength range from 1638 to 1646 nm was demonstrated on the basis of a single 4500 µm-long InAs/InGaAsP quantum dot Fabry-Perot cavity chip. All channels were stable because of inhomogeneous gain broadening due to statistically distributed sizes and geometries of self-assembled quantum dots. [ABSTRACT FROM AUTHOR]

A highly efficient non-degenerate four-wave mixing (FWM) process using CW pump and probe signals around the L-band wavelength range in an InAs/InGaAsP quantum dot semiconductor optical amplifier (QD-SOA) is experimentally demonstrated for the first time. The preliminary experimental results indicate that the FWM efficiency using QD-SOA is independent of the sign of the frequency detuning and decreases by less than 20 dB/decade with frequency detuning increasing. [ABSTRACT FROM AUTHOR]

We have studied the tuning behavior of an external cavity laser in Littrow configuration using antireflection/high-reflection coated InAs/InGaAsP/InP quantum dot laser diodes as the amplifying element. Adding the coatings improves the performance of the setup, and the tunability of the external cavity laser output has been increased up to 166 nm. Detailed investigations have revealed that laser diode length and width influence the magnitude of the tuning range. Furthermore, the external differential quantum efficiency is systematically increasing as the external cavity laser wavelength is decreasing. These characteristics are discussed in terms of energy levels available in the inhomogeneous broadening of the self-assembled quantum dots. [ABSTRACT FROM AUTHOR]

The optical performance of external-cavity lasers based on InAs/InGaAsP quantum dot laser diodes is investigated. The broad electroluminescence reveals a gain spectrum with full width at half maximum of at least 175 nm. By fabricating as-cleaved ridge lasers of different length and width, tuning ranges as high as 110 nm have been achieved at wavelengths encompassing 1.55 μm. The tuning ranges and efficiencies obtained are limited by internal losses and competition between the external-cavity lasing modes and the laser diode natural lasing modes. The laser diode length is found to affect both the wavelength tuning range and the threshold current density, which is consistent with a quantum-dot type density of states. [ABSTRACT FROM AUTHOR]

A high performance ridge-waveguide InAs/InP quantum dot distributed feedback laser around 1.52 µm with a cavity length of 1 mm and a stripe width of 3 µm is demonstrated. In continuous-wave operation singlemode output power was up to 18.5 mW and its sidemode suppression ratio was greater than 62 dB. The relative intensity noise was measured to be less than -154 dB/Hz from 10 MHz to 10 GHz, and the optical linewidth smaller than 150 kHz when the injection current was 200 mA at room temperature of 18°C. [ABSTRACT FROM AUTHOR]

Abstract: The optical performance of InAs/InGaAsP quantum dot (QD) lasers grown on (100) InP was studied for three different material structures. The most efficient QD laser structure, having a threshold current of ∼107mA and an external differential quantum efficiency of 9.4% at room temperature, was used to form the active region of a grating-coupled external cavity tunable laser. A tuning range of 110nm was demonstrated, which was mainly limited by the mirror and internal losses of the uncoated laser diode. Rapid state-filling of the QDs was also demonstrated by observing the evolution of the spectra with increasing injected current. [Copyright &y& Elsevier]