We demonstrate high-power operation of both individual broad-waveguide separate-confinement-heterostructure quantum-well InGaAsP-InP laser diodes and 1-cm-wide arrays emitting at 1.83 μm. Despite strong dependence of threshold current density and diode efficiency on operating temperature, a continuous-wave output power of 2.1 W has been obtained for 100-μm-aperture lasers with 2-mm-long cavities. An output power of 11.5 W was reached for ten element 1-cm-wide array at a heatsink temperature of 16/spl deg/C.
Reduction of internal loss and a twofold increase of differential efficiency have been obtained for 1.5 µm wavelength InGaAsP/InP separate confinement multiquantum well long cavity lasers with broadened waveguides. A record CW output power of 4.6 W has been demonstrated for a laser with a 200 µm aperture.
We report a novel bi-level etching technique that permits the use of standard photolithography for coupling to deeply etched ring resonator structures. The technique is employed to demonstrate InGaAsP laterally coupled racetrack ring resonators laser with record low threshold currents of 66 mA. The racetrack laser have curved sections of 150-μm radius with negligible bending loss. The lasers operate continuous-wave single mode up to nearly twice threshold with a 26-dB side-mode-suppression ratio. Bi-level etching is of interest for fabrication of mesoscopic or microcavity photonic resonator structures without relying on submicrometer processing.
High power ridge-waveguide (RWG) lasers with emission wavelengths from 1400 to 1480 nm have been developed to meet the demands of high channel density EDFA and Raman amplification systems. Output power levels as high as 1 watt from the RWG device can be effectively coupled to single-mode optical fiber producing ex-fiber powers as high as 710 mW.
Many simple molecules, such as H2O, CO2, CO, N2O, CH4, and HCN, have strong absorption bands at wavelengths between 2 and 3.5 micrometers . We are developing InGaAsSb/AlGaAsSb multi-quantum-well diode lasers operating from 2 to 3.5 micrometers as sources for trace-gas monitors. These devices are grown by molecular beam epitaxy, and they generally comprise four or five InGaAsSb quantum wells separated by AlGaAsSb barriers. The cladding layers are high-Al-content AlGaAsSb layers. Our longest-wavelength, room- temperature (20 degree(s)C) lasers operate at 2.78 micrometers in the pulsed mode, delivering 95 mW peak power. The highest temperature for pulsed-mode operation is 60 degree(s)C, at which the wavelength is 2.9 micrometers . Between 78 and 200 K they operate cw, and at 200 K the output is 3 mW at 2.66 micrometers in a dominant single mode. We discuss the properties of these lasers along with some initial applications to water-vapor detection.
We have demonstrated continuous wave operation of 2.7-μm InGaAsSb/AlGaAsSb multiquantum-well diode lasers up to a temperature of 234 K (−39 °C). These devices were grown by molecular-beam-epitaxy. They have a tendency to operate in a dominant single mode over well-defined temperature and current intervals. A comparison of spontaneous emission spectra shows that above threshold, the quasi-Fermi level is pinned and that most of the carriers are injected into nonlasing states. This effect leads to a rapid decrease of differential efficiency with increasing temperature.
We have observed laser action in InO7GaO3AsO72SbO28 IInPO.7SbO.3 double heterojunction, diode lasers at ? = 3.06 .tm. The maximum operating temperature was 35 K. The threshold current densities were in the range of 200 - 330 A /cm These devices were grown by organometallic vapor-phase epitaxy.
This paper describes the design, fabrication and performance of two monolithic GaAs C-band 900 interdigitated couplers with 50-ohm and 25-ohm impedances, respectively. A comparison of the performance of these two couplers shows thar the 25-ohm coupler has the advantages of lower loss, higher fabrication yield and needs fewer numbers of matching elements when it is used in the balanced amplifier configuration. The fewer number of matching elements results in great savings in the GaAs real estate for MMICS. Both the couplers have been fabricated on a 0.1 mm thick GaAs SI substrate. The measured results agree quite well with calculated results. The losses of the 50-ohm and 25-ohm couplers are 0.5 and 0.3 dB, respectively, over the 4-8 GHz frequency band.
