The invention provides an F-P (Fabry-Perot) cavity strained 
quantum well 
laser with low linewidth. The F-P cavity strained 
quantum well 
laser comprises a substrate (1), a buffer layer (2), an n type lower limiting layer (3), a lower 
waveguide layer (4), a lower 
barrier layer (5), an 
active layer (6), an upper 
barrier layer (7), an upper 
waveguide layer (8), a p type upper limiting layer (9) and an 
ohmic contact layer (10) which are sequentially connected. Through the 
optimal design of the 
active layer (6), a linewidth enhancement factor generated by interband transition of a 
quantum well and a linewidth enhancement factor generated by 
free carrier absorption and band-gap shrinkage can offset mutually, thereby realizing the low linewidth and improving the quality of a 
light beam of the 
quantum well laser. The 
active layer of the laser provided by the invention is made of InxGa1-xAs materials, wherein x is equal to 0.33, the width thickness of the well is 3-5nm, the center 
wavelength lambda is equal to 980nm-1036nm, and the linewidth of the F-P cavity strained 
quantum well laser can be reduced by three orders of magnitude in comparison with a 
quantum well laser. The F-P cavity strained 
quantum well laser can be used for optical measurement, 
solid-state 
laser pumping, laser 
spectroscopy research and other fields.