quantenkaskadenlaser inspiration by optical phononen

摘要

Quantum cascade laser includes waveguide comprising gain region (14) having layers (20) incorporating alternating quantum barrier (22) and quantum well (24) strata. Each layer (20) is arranged such that the active zone includes three sub-bands whose potential differences are such that an electron transition between the two most distant sub-bands emits energy for emission of two optical photons. Quantum cascade laser comprises two electrodes for applying a control electric field and a waveguide located between the electrodes and which comprises a gain region (14) formed of numerous layers (20) consisting of alternating quantum barrier strata (22) and quantum well strata (24), constituting first and second types of semiconductor materials, respectively; and two optical confinement layers located on either side of the gain region. Each layer (20) of the gain region (14) comprises an injection barrier (26) and an active zone (28) formed from at least three pairs of strata, each pair being formed of a first-type stratum (22) and a second-type stratum (24). The strata in the active zone of each layer (20) are arranged such that each quantum well has at least one first upper sub-band (F), a second intermediate sub-band (G) and lower third (H) and fourth (J) sub-bands. The potential difference between the second and third sub-bands on the one hand and the third and fourth sub-bands on the other hand are such that an electron transition from the second to the third sub-band and from the third to the fourth sub-band, respectively, emits energy (E(GH)), E(HJ)) corresponding to that necessary for the emission of an optical phonon.