L. Le Gouezigou

Photonic-crystal ultrashort bends with improved transmission and low reflection at 1.55 μm

We propose and demonstrate improved designs in order to increase the transmission level through double 60°-bend photonic-crystal-based waveguides. These bends are defined in a two-dimensional photonic crystal (PC) patterned into a GaInAsP slab on InP substrate. Transmission spectra calculated using a two-dimensional finite difference time domain method that accounts for radiation losses, as well as measurements, demonstrate enhancement of the transmission when moving holes in the corner. As expected a drop in reflection is obtained. The sensitivity to the PC guide width is also evidenced.

High Bandwidth Operation of Directly Modulated Laser Based on Quantum-Dash InAs–InP Material at 1.55

The modulation bandwidth has been identified as a specific limitation of quantum-dot or quantum-dash (QDash) lasers for direct modulation application. Solutions using tunnel injection and p-doping have already been demonstrated to increase the modulation bandwidth above 10 GHz, but with complex tunnel injection design and p-doping induced high internal losses. We show in this letter that the use of optimized QDashes and waveguide structure is sufficient to reach such high bandwidth at 1.55 mum. The device is validated by a large signal modulation demonstration at 10 Gb/s.

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Monolithic and mono-section InAs/InP quantum dot Fabry-Perot laser diodes are fabricated and characterized in an actively mode-locked mode for ultra-stable clock signal generation. Electrical line-width as narrow as the 10 Hz detection resolution is obtained

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Measurements of SOA with various optical confinements show that low confinement devices are not saturated by ASE. This allows them to have good inversion factors at their input section, which leads to state-of-the-art noise factors.

Active Mode-Locking of Quantum Dot Fabry-Perot Laser Diode

Abstract Fe doped semi-insulating InP layers have been grown by gas source MBE with a solid iron source. Structure as n-i-n, p-i-n and p-n-i-n were characterized by I ( V ) measurements and secondary ion mass spectroscopy profiling (SIMS). As shown by SIMS, uniform Fe doping and abrupt transitions are achieved for the different structures studied. Resistivities as high as 1.5×10 9 Ω cm are determined from I ( V ) curves for Fe concentrations in the 10 17 cm -3 range. Lasers with semi-insulating layers have been realized for the first time by gas source MBE. Preliminary results show power emission of 43 mW, without antireflecting coating, comparable to state-of-the-art characteristics.

Experimental study of the impact of optical confinement on saturation effects in SOA

We investigate the devices performances of InAs/InP (100) quantum dash buried stripe ridge lasers. We demonstrate high-gain quantum dash based lasers whose dynamic properties are compatible with high-speed devices requirements. The good temperature characteristic of such lasers allows 10 Gb/s direct modulation in the temperature range of 25-75degC. The mode-beating RF spectrum of passively locked FP quantum dashes laser shows a very narrow spectral linewidth (50 kHz) attributed to a strong phase correlation between modes

Growth of semi-insulating InP by GSMBE

Monolithic quantum dot Fabry-Perot laser diodes are fabricated and characterized for ultra-stable clock signal generation. Pulse width of 7ps and electrical line-width as narrow as 2 kHz are obtained.

Buried ridge stripe lasers using InAs/InP (100) quantum dashes based active layer: a step towards low noise sources for high-speed direct modulation

We investigate in detail the influence of the tunneling-injection design on the device performances of InAs/InP QDashes-based broad-area lasers. Using optimum design, high-performances single mode buried ridge stripe Fabry-Perrot lasers are reported (external efficiency of ~0.17 W/A per facet and threshold current of ~16 mA for as-cleaved 600 mum-long cavity). A relaxation frequency of 8.5 GHz is reported, indicating the good potential of such design for 10 Gb/s direct modulation, and the actual limitations of small-signal modulation bandwidth are discussed.

Ultra-Narrow Mode-Beating Spectral Line-Width of a Passively Mode-Locked Quantum Dot Fabry-Perot Laser Diode

This paper reports the first results on Fabry-Perot 1.3 /spl mu/m lasers with sub-micron tapered active layers defined using a UV-250 patterning technology in combination with conventional RIE processing of InP. Its implementation to the full 2 inch wafer process flow is of interest in low cost module fabrication. Short lasers (500 /spl mu/m) with low coupling loss (3.4 dB with end cleaved fiber) and high quantum efficiency (0.26 W/A at 85/spl deg/C) are demonstrated.

Optimization of Tunneling-Injection InAs/InP (100) Quantum Dashes Lasers for High-Speed Optoelectronic Devices

Abstract Buried ridge stripe lasers have been grown on InP in two steps by gas source molecular beam epitaxy. The active structure consists of a compressively strained layer multi quantum well with an equivalent wavelength emission at 1.5 μm. The stripe was defined by reactive ion etching. A threshold current of 22 mA was reproducibly obtained on a laser length of 500 μm. A CW output power of 48 mW per facet was achieved. In addition, preliminary accelerated aging tests have shown the high reliability of the structure.