Raymond J. Menna

Ultralow‐loss broadened‐waveguide high‐power 2 μm AlGaAsSb/InGaAsSb/GaSb separate‐confinement quantum‐well lasers

Broadening the waveguides of 2 μm AlGaAsSb/InGaAsSb separate‐confinement multiquantum‐well lasers decreases their internal losses to 2 cm−1, while threshold current densities remain as low as 300 A/cm2. The consequently high cw differential efficiency of 0.36 results in output powers of 1.2 W from 100 μm aperture lasers at 15 °C.

4 W quasi-continuous-wave output power from 2 μm AlGaAsSb/InGaAsSb single-quantum-well broadened waveguide laser diodes

AlGaAsSb/InGaAsSb single-quantum-well (SQW) laser diodes emitting at 2 μm were fabricated and tested. At 10–15 °C, the uncoated SQW lasers with 2–3 mm cavity lengths exhibit a threshold current density of 115 A/cm2, a continuous-wave output power of 1.9 W, a differential efficiency of 53%, and a quasi-continuous-wave output power of 4 W. Their performance deteriorates rapidly as output losses increase beyond 10 cm−1.

Room‐temperature 2.78 μm AlGaAsSb/InGaAsSb quantum‐well lasers

We describe room‐temperature 2.78 μm AlGaAsSb/InGaAsSb multiquantum well lasers. Pulsed laser operation was observed at 15 °C with a threshold current of 1.1 A (10 kA/cm2), and a maximum power output of 30 mW, and a maximum differential quantum efficiency of 9%. Lasers operated pulsed up to 60 °C with a characteristic temperature of 58 K over the range of 0–40 °C. To date, 2.78 μm is the longest emission wavelength for a room‐temperature III–V laser.

Low-threshold InGaAsP ring lasers fabricated using bi-level dry etching

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-/spl mu/m 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.

3.06 μm InGaAsSb/InPSb diode lasers grown by organometallic vapor‐phase epitaxy

We have observed laser action at λ=3.06 μm in In0.77Ga0.23As0.74Sb0.26/InP0.7Sb0.3 double heterojunction, diode lasers, which were grown by organometallic vapor‐phase epitaxy. The maximum operating temperature was T=35 K, and typical threshold current densities were 200–330 A/cm2. At temperatures up to 35 K, the lasing wavelength decreased with increasing temperature owing to a band‐filling effect.

Design of an open path near-infrared diode laser sensor: application to oxygen, water, and carbon dioxide vapor detection.

An open path diode laser sensor was constructed with near-infrared diode lasers and two-tone frequency-modulation spectroscopy. The sensor incorporates several novel features (such as digital signal-processing algorithms, a computerized line-locking routine, and discontinuous wavelength scanning) that are important in a field instrument. The sensor was used to monitor oxygen, water, and carbon dioxide in the near-infrared spectral range. For oxygen, an absorbance detection sensitivity of 2 × 10(-6) in a 10-Hz bandwidth was demonstrated with a GaALAs laser at 760.56 nm. The stability of the sensor was 0.1% over a period of 10 h when an absorbance of 6 × 10(-3) was monitored.

Measurement of 12 CO 2 : 13 CO 2 ratios for medical diagnostics with 1.6-μm distributed-feedback semiconductor diode lasers

We have observed some of the absorption lines from the molecules (12)CO(2) and (13)CO(2)in the 1.6-µm spectral region with the use of specially fabricated single-mode InGaAsP distributed-feedback semiconductor diode lasers. Using a 23.6-m-long multipass absorption cell in combination with radio-frequency modulation and detection techniques, we measured the (12)CO(2):(13)CO(2) isotopic ratio of two specific lines at 6253.73 and 6253.90 cm(-1) with sufficient precision for diagnostic medical tests that analyze CO(2) on human breath.

2.7‐μm InGaAsSb/AlGaAsSb laser diodes with continuous‐wave operation up to −39 °C

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.

1.95-/spl mu/m strained InGaAs-InGaAsP-InP distributed-feedback quantum-well lasers

Distributed-feedback emission from strained InGaAs-InGaAsP-InP quantum well lasers has been examined over a temperature range of 130 K to 300 K. Continuous single-mode output from 190 to 300 K with a side-mode-suppression ratio of about 10 dB was observed. The wavelength was 1.95 /spl mu/m at 273 K and tuned at a rate of 0.13 nm/K. The current-tuning rate was 0.0043 nm/mA (-340 MHz/mA) at 273 and 283 K.<<ETX>>

Effect of heterobarrier leakage on the performance of high-power 1.5 μm InGaAsP multiple-quantum-well lasers

Broad stripe 1.5 μm InGaAsP/InP multiple-quantum-well graded-index separate-confinement heterostructure lasers with different waveguide widths and doping profiles were designed, fabricated, and characterized. A record value of more than 16 W of pulsed optical power was obtained from lasers with a broadened waveguide design. Studies of the characteristics of lasers with different p-doping profiles as well as modeling data show that the heterobarrier electron leakage is responsible for the effect of the device optical power saturation with current.