Optical Science and Engineering ETDs


Xiang He

Publication Date



Optically-pumped type-II mid-infrared index-coupled tunable distributed feed- back (DFB) semiconductor lasers have been developed to provide continuous-wave (CW) single longitudinal mode (SLM) operation with features including narrow spec- tral linewidth, high output power, good beam quality and wide continuous wave- length tunability for applications such as remote sensing or spectroscopy in the 3 to 5 μm midwave-infrared range of atmospheric transmission window. In the demonstration of this type of laser, a hyperbolically chirped grating was patterned using interferometric lithography (IL) with spherical wavefronts which was then transferred into the top clad of the slab waveguide epi-structure of the laser de- vice. Wavelength tuning is achieved by translationally projecting pump stripe at di\ufb00erent positions of this chirped grating on the laser device, thus di\ufb00erent grat- ing periods along the pump stripe at di\ufb00erent pump positions select di\ufb00erent las- ing wavelengths. Primary results were acquired on one device of 4 mm in lateral dimension with continuously tuning range of about 80 nm centered at 3100 nm, single facet output power of 830 mW and typical spectral linewidth of 1.2 nm at 2.5xthreshold pumping. Fabry-Perot (F-P) interferometer was used as arti\ufb01cial tar- get gas to demonstrate potential application of gas spectroscopy with this type of laser.

Degree Name

Optical Science and Engineering

Level of Degree


Department Name

Optical Science and Engineering

First Advisor

Brueck, Steven

First Committee Member (Chair)

Sheik-Bahae, Mansoor

Second Committee Member

Kaspi, Ron

Third Committee Member

Hayat, Majeed

Fourth Committee Member

Eliseev, Petr

Document Type