Abstract: The invention relates to the design and processing of a semiconductor optical device. The device is formed of at least four layers of III-V compounds in which one consists of the penternary AlGalnAsSb material. The structure is wet etched in order to form optical ridge waveguides. One such device has incorporated two waveguides which are connected through a new junction design which can be made by wet etching. In one design the junction and waveguides consists of wet etched AlO .90GaO .10AsSb cladding around a core of AlO .28GaO .72AsSb in which an active layer composed of AlO.22InO.22GaO.55AsSb/InO.29GaO.71AsSb quantum wells is embedded. The resulting device is a erdge junction laser which has single mode emission and emits a narrow line width. We made and tested a device in the 2.34 müm to 2.375 müm wavelength area and found it to have an emission line width of around 0, 5 nm.

Abstract: The subject invention relates to a new alarm which is based on using a quarternary tunable Mid-IR laser to measure both particles and gas at the same time. The measurement is done within an area of which the gas of interest will absorb the Mid-IR radiation. By widely tuning the emission wavelength of the laser, several wavelengths can be measured in order to accurately find both gas composition and particle density with one laser based sensor. We tested a new device which use radiation between 2.27 ?m and 2.316 ?m. Methane gas reduces intensity of the radiation at certain wavelengths in this device, while particles/fog reduce intensity for all wavelengths. In this case, fog should not trigger an alarm, while methane leaks should. This can also be applied for CO and smoke in which one sensor will measure both parameters to sound an alarm instead of just one parameter.