Semiconductor laser device

摘要

A separate confinement heterostructure (SCH) laser device (LD) has a quantum well active region 10 within an optical guiding region 12, and n- and p-type cladding regions 14 and 16 on opposite sides of the guiding region 12. An electron-capture layer 36 is provided in the n-side guiding region 12a. The composition of the electron-capture layer 36 is such that the minimum energy for X-electrons in the conduction band is lower than that in the surrounding parts of the active region 10 and/or the n-side guiding region 12a. The electron-capture layer 36 is thick enough to bind X-electrons so that, in use, the electron-capture layer 36 promotes the capture of X-electrons. The electron-capture layer 36 is sufficiently close to the active region 10 to permit transfer of captured X-electrons to at least one r-confined level in the active region 10.