1.3 mu m semiconductor laser power amplifier

The performance of a 3.4-Gb/s system using a low-power 1.318- mu m distributed-feedback (DFB) laser transmitter and a traveling-wave semiconductor laser power amplifier is studied. The -14.5-dBm, input from a directly modulated DFB laser is boosted to +10.3 dBm, of which +4.8 dBm is coupled into the transmission fiber. The penalty, caused by amplifier noise and pattern effects due to gain saturation, is less than 0.5 dB.<>     

High reliability low-threshold InGaAsP ridge waveguide lasersemitting at 1.3 μm

The fabrication, performance, and reliability of InP/InGaAsP ridge waveguide lasers emitting at 1.3 μm is described. The structure requires only one stage of planar wafer growth and simple fabrication steps and is therefore an inherently low-cost product. Threshold currents are typically 25-30 mA, and the external quantum efficiency is 20-25% per facet. Output power in the fundamental mode is maintained to above 10 mW, while total power in excess of 100-mW CW at 20° has been obtained. The life test data have been fitted to a power-law drift model to predict long-term behavior and is consistent with total lifetimes in excess of 25 years. The device is eminently suited for applications in high-reliability high-capacity fiber-optic communications systems     

CW operation of GaInAsP buried ridge structure laser at 1.5 ?m grown by LP-MOCVD

A GaInAsP buried ridge structure laser (BRSL) emitting at 1.5 ?m and fabricated on material grown entirely by LP-MOCVD is described for the first time in the letter. Threshold currents of 40 mA DC and an output power up to 15 mW have been obtained at room temperature. CW operation up to 60°C has been achieved.     

Threshold reduction of 1.3 mu m GaInAsP/InP surface emitting laser by a maskless circular planar buried heterostructure regrowth

A newly introduced maskless planar buried heterostructure regrowth has substantially improved the regrown heterointerface of a 1.3 mu m GaInAsP/InP circular buried heterostructure surface emitting laser. The threshold current of the 12 mu m phi device was reduced to 2.2 mA at 77 K under CW conditions.<>     

Mode-locking of diode laser-pumped Nd:YAG laser at 1.3 mu m

Reports on the development of a mode-locked AlGaAs diode laser pumped Nd:YAG laser operating at 1.3 mu m. The laser produces pulses of 47 ps duration with a time-bandwidth product of 0.42, which is close to the limit for Gaussian pulses.<>     

Opening the 1.5 mu m window in 1.3 mu m regenerated systems

The authors introduce a novel upgrade technique for currently installed 1.3 mu m regenerated optical transmission systems that can be implemented with minimal disturbance to existing plant. The method uses erbium fibre amplifiers to bypass regenerators thus opening the 1.5 mu m window. The concept is discussed and an experiment reported to illustrate the scheme.<>     

Novel hemispherical vertical cavity 1.3 mu m surface-emitting laser on semi-insulating substrate

A vertical cavity GaInAsP/InP surface-emitting laser at 1.3 mu m wavelength is demonstrated with a hemispherical cavity structure. The laser consists of a circular mesa buried (passivated) in polyimide and is made on a semi-insulating InP substrate. CW operation was obtained at 77 K with a threshold current density of 90 kA/cm/sup 2/.<>     

Performance of an improved InGaAsP ridge waveguide laser at 1.3 ?m

Single-mode, CW ridge lasers at 1.3 ?m have been made with threshold currents as low as 125 mA at 25°C using a symmetrical wafer structure. Performance is interpreted in terms of ridge guiding and injected carrier antiguiding.     

Extremely low threshold operation of 1.5 mu m GaInAsP/InP buried ridge stripe lasers

1.5 mu m Fabry-Perot lasers exhibiting extremely low threshold currents have been obtained with a buried ridge stripe (BRS) structure. Threshold currents are 5.7 and 15.5 mA for 300 mu m and 1 mm cavity lengths, respectively, in CW operation. The optical losses of the buried waveguide have been determined from the external quantum efficiency dependence with cavity length.<>     

High-power high-reliability operation of 1.3 µm p-substrate buried crescent laser diodes

Stable high-power CW operation of 1.3-μm InGaAsP/InP p-substrate buried crescent laser diodes (PBC-LD'S) has been realized, by controlling the front and rear facet reflectivities of the laser diode chips. The front facet reflectivity is reduced to 17 percent and the rear facet reflectivity is increased to 90 percent, by evaporating multilayer dielectric films (Si/Al2O3SiO2:17 percent, SiO2/Si/SiO2/Si/SiO2:90 percent) on each facet. CW light output power of 50 mW is achieved up to 60°C. Aging tests have been carried out under automatic power control (APC) mode conditions of 50°C-30 mW, 40 mW, 50 mW, and 30°C-50 mW. All samples are operating stably in spite of junction-up configuration. The lifetimes are estimated to be more than2 times 10^{4}h for all conditions.     

1.55 ?m InGaAsP low-threshold buried-crescent injection laser

Fabrication of 1.55 ?m InGaAsP buried-crescent (BC) injection lasers with a p-n-p-n blocking structure is described. The BC lasers exhibit a threshold current as low as 14 mA at 25°C, very high yield, output power more than 10 mW and high-temperature operation up to 80°C. These BC lasers have continued to operate in stable CW mode at 50°C for more than 1000 h. The lifetime of the 1.55 ?m InGaAsP lasers at 50°C is estimated to exceed about 2.5 × 104 h.     

Highly reliable 1.3 /spl mu/m InGaAlAs buried-heterostructure laser fabricated with in-situ cleaning

An in-situ-cleaned and regrown 1.3 /spl mu/m InGaAlAs buried-heterostructure laser was fabricated for the first time. The degradation of its driving current was about 1% after a 3000 h aging test. It can thus be concluded from this result that in-situ cleaning is a promising means of fabricating highly reliable, high-performance InGaAlAs BH lasers.     

1.3 /spl mu/m quantum dot vertical-cavity surface-emitting laser with external light injection

A 1.3 /spl mu/m quantum dot vertical-cavity surface-emitting laser (QD VCSEL) with external light injection is presented, having been experimentally demonstrated. The QD VCSEL is fabricated on GaAs substrate. The 3 dB frequency response of the QD VCSEL based on the TO-Can package is enhanced from the free-running 1.75 to 7.44 GHz with the light injection technique.     

Silicon Mach-Zehnder waveguide interferometers operating at 1.3 mu m

Mach-Zehnder waveguide interferometers have been fabricated in silicon and operation has been demonstrated at lambda =1.3 mu m. The switching mechanism is based on the thermally induced variation of the refractive index of crystalline silicon. Modulation depths of 40% were obtained for switching powers of 30 mW and switching times of 50 mu s.<>     

Comparative study of low-threshold 1.3 μm strained andlattice-matched quantum-well lasers

A study of the effects of biaxial strain on the performance of low-threshold 1.3-μm In_xGa_1-xAs_yP _1-y/InP quantum-well lasers is presented. Lasers with lattice-matched, compressive-strained, and tensile-strained quantum-wells were fabricated to compare the effect of strain on various device parameters. Threshold current densities as low as 187 A/cm² for a two-quantum-well device with 0.85% compressive strain were obtained     

InGaAsP/InP buried crescent laser diode emitting at 1.3 µm wavelength

The fabrication procedure, designing of an active region and a p-n-p-n current blocking structure, characteristics and the aging results of an InGaAsP/InP buried crescent (BC) laser diode are described. The BC laser diodes exhibit high laser performances, such as a low-threshold current, a fundamental transverse mode oscillation with linear light output-current characteristics. CW operation at as high as 100°C is achieved with a junction up configuration as a result of the improvement in the current blocking structure. A stable CW operation at 80°C has been realized with a constant optical output power of 5 mW.     

Room-temperature low-threshold type-II quantum-well lasers at 4.5 /spl mu/m

We report optically pumped InAs-InGaSb-InAs-AlSb type-II quantum-well lasers at 3.84-4.48 /spl mu/m. Lasing was observed at temperatures up to 300 K with a characteristic temperature T/sub 0/ of 61.6 K. The average absorbed threshold power was only 0.7 mW at 220 K, and 2.7 mW at 300 K with a pulselength of 650 ns and a repetition rate of 2 kHz. At 49 K, the continuous-wave (CW) output power was 4.2 mW/facet with an absorbed threshold pump power of 31.5 mW and an absorbed pump power of 62 mW, indicating a differential quantum efficiency of 54% for two facets.     

High temperature CW operation of p-substrate buried crescent laser diode emitting at 1.3 ?m

A 1.3 ?m InGaAsP/InP buried crescent laser diode has been fabricated on p-InP substrate. The laser diode has a low threshold current, as low as 10 mA. It operates at the output power of 5 mW under CW condition at temperatures higher nary aging test at 70°C with a constant light output of 5 mW, the lasers have been operating stably for more than 1000 h.     

GaAs-based four-channel photonic crystal quantum dot laser module operating at 1.3 /spl mu/m

A GaAs-based laser module, which combines the output of four singlemode lasers operating at 1.3 /spl mu/m by using photonic crystal mirrors and combiners, has been developed. The complete device size is around 0.2 mm/sup 2/. The lasers can be operated individually or in parallel with sidemode suppression ratios better than 20 dB.