Agile and fast switching monolithically integrated four wavelengthselectable source at 1.55 μm

We demonstrate 4-nm spaced four emitted wavelengths on a single output waveguide in a four channel DBR lasers array monolithically integrated with a 4>1 coupler. Using distributed Bragg reflector tunability, all wavelengths within a 16-nm range can be reached with an accuracy better than 0.2 nm. Wavelength switching time measured at 90% of nominal power is 4 ns     

Short-cavity GaAlAs laser by wet chemical etching

A short-cavity (GaAl)As stripe geometry laser with a threshold current of 30 mA has been fabricated by a new chemical etch process which uses a multilayer metal mask. The laser is 23 ?m long and 12 ?m wide, and does not have reflective coatings on the etched facets. Quasi-single-mode operation is obtained in pulsed conditions.     

Picosecond (<2.5 ps) wavelength-tunable ( approximately 20 nm) semiconductor laser pulses with repetition rates up to 12 GHz

A novel technique is used to produce picosecond wavelength-tunable optical pulses from gain-switched Fabry-Perot semiconductor lasers using fibre compression. Experiments are carried out with high power, large modulation-bandwidth lasers at 1.3 mu m. Pulses of 2.5 ps durations with repetition rates up to 12 GHz are obtained. Still shorter pulses ( approximately 1 ps) with higher repetition rates (18 GHz) are shown to be feasible.<>     

GaAs:GaAlAs ridge waveguide lasers and their monolithic integrationusing the ion beam etching process

The fabrication and performance characteristics of GaAs/GaAlAs ridge waveguide lasers are discussed. Threshold currents as low as 8 mA and differential quantum efficiencies as high as 90% were obtained for 250-μm-long graded-index separate-confinement heterostructure with single quantum well (GRINSCH SQW) lasers. High-speed short-cavity ridge waveguide lasers for which both the ridge stripe and one-mirror facet were formed by Ar-ion beam etching were achieved. The dependence of threshold current and lasing spectra on the cavity length were theoretically and experimentally investigated. This process was successfully used to integrate a laser diode monolithically with a photodiode or a field-effect transistor     

Low-damage dry-etched grating on an MQW active layer anddislocation-free InP regrowth for 1.55-μm complex-coupled DFB lasersfabrication

A grating dry-etched through the upper wells of a multiquantum-well active layer has been characterized before and after regrowth. TEM observation and carrier lifetime measurements have shown growth-free defects of the epitaxial layers. As a consequence, quasi-100% monomode oscillation on λ+1 mode has been achieved on complex-coupled distributed-feedback GaInAsP QW lasers fabricated with such grating     

Dual-wavelength (GaAl)As laser

A monolithic structure integrating two stripe-geometry (GaAl)As lasers emitting at 8500 and 8850 ? is described. The threshold currents for both lasers are in the 50?70 mA range. The spacing between the stripes for the device reported here is 25 ?m; it can be reduced to 10 ?m in order to optimise the direct coupling to a 50 ?m diameter fibre.     

Integration of a laser diode with a polymer-based waveguide forphotonic integrated circuits

The fabrication and characterization of BRS lasers monolithically integrated with butt-coupled polymer-based buried strip waveguides is presented. Threshold currents of lasers with one cleaved and one etched mirror facets are 15-18 mA and waveguide output powers are in excess of 5 mW at 100 mA laser driving currents and for 600 μm long waveguides. The device exhibits a total waveguide insertion loss less than 5 dB. The integrated device is potentially suitable as a building-block for photonic integrated circuits     

Fabrication and characteristics of ion beam etched cavity InP/InGaAsP BH lasers

A low temperature ion beam etching (IBE) process is successfully applied to facet mirror fabrication of 1.3 μm InGaAsP/InP buried heterostructure (BH) lasers. Ar ion beam etching characteristics of InP are studied and masking conditions are optimized for obtaining low-damage, vertical, and smooth etched facets. Lasers fabricated by this technique have threshold currents and quantum efficiencies comparable to those of lasers with conventionally cleaved mirrors. CW operation at room temperature has been achieved. Initial experimental results of preliminary aging tests are also presented.     

Proposal and demonstration of a symmetrical npipn electroabsorptionmodulator

We propose a new type of electroabsorption modulator based on a npipn diode structure. Its transmission curve versus applied bias should be symmetrical with respect to zero bias. A npipn InGaAs-InAlAs multiple-quantum-well (MQW) modulator has been fabricated to experimentally demonstrate two applications for optical fiber transmission systems: pulse generation with adjustable duty cycle for optical time division multiplexing and harmonic generation up to 40 GHz for millimeter radiowave transport on optical fiber     

Low threshold GaAs/GaAlAs BH lasers with ion-beam-etched mirrors

We report the use of the ion-beam etching (IBE) technique to produce GaAs/GaAlAs BH lasers with one etched and one cleaved mirror facet. Low threshold currents of 12 mA have been measured in devices with 100 ?m-long cavities.