A sampled grating distributed Bragg reflector laser diode for spectroscopic based multi-gas detection at 1.5 /spl mu/m

Summary form only given. We report the first use of a sampled grating distributed Bragg reflector (SGDBR) widely tunable laser (/spl Delta//spl lambda/=50 nm) to laser based gas detection. The laser was used to simultaneously measure the concentration of several gas species with widely separated absorption features. Such wide wavelength scanning is not possible with conventional DFB and DBR lasers and is in high demand for tunable laser diode absorption spectroscopy trace gas detection. The SGDBR consists of four independently biased sections; a front and back sampled grating mirror, a phase section and a gain section The device can access wavelengths over the range 1520 nm/spl les//spl lambda//spl les/1570 nm while maintaining a side mode suppression of >30 dB. By holding one grating at fixed bias and varying the refractive index of the other grating discontinuous tuning is achieved. Continuous tuning is obtained by simultaneously changing the refractive index in the two gratings. This combination of discontinuous and continuous tuning gives full wavelength coverage over 30 nm.