Overgrowth on InP corrugations for 1.55μm DFB LDs by reduction of carrier gas flow in LPMOCVD

Effect of crystal thickness of separate confinement heterostructure layers on 1.55‐μm loss‐coupled dfb laser characteristics

“…In figure 3, we took the microscopic images of the epitaxial layers by transmission electron microscope (TEM) and by scanning electron microscope (SEM). From the TEM image in figure 3(a), we could distinct each layers such as multi-quantum wells in narrow strip lines, SCH layer, InP spacer, InGaAsP overgrowth layer, and the InAsP absorptive corrugated layer [11] (small triangular region marked by the arrow was proven to be an InAsP layer [12]). Then, we tried to change the thickness of SCH crystal layers of 1.25-µm bandgap wavelengths below and above the MQW from the original 40-nm to 80-nm and 120-nm in which the coupling coefficient modifies relying on the thicknesses of these crystal layers.…”

“…However, additional growth step for insertion of an absorption medium in the grating is required, compared to the steps of an index-coupled device [10]. In the previous results of 1550-nm loss-coupled laser, the overgrowth mechanism to achieve automatically buried absorptive InAsP layer were shown so that we could fabricate loss-coupled 1550-nm DFB laser diodes with simple growth mechanism without steps for absorption medium and the reviews of recent results in complexcoupled (including gain-and loss-coupling mechanisms) laser diode were also covered in [11][12][13].…”

“…To implement a loss-coupled mechanism of DFB lasers, an automatically buried absorptive InAsP layer was grown between the valley of a corrugated InP and an InGaAsP layer (1.10-µm) by introducing a new overgrowth method in the previous study [11]. As in figure 1(a), an InP spacer was inserted inside the InGaAsP layer (1.10-µm).…”

Monte-carlo computations for predicted degradation of photonic devices in space environment

“…InGaAsP/inP active zone with multi quantum wells (MQW) consists in 3 nm thick wells, with a compressive strain 1 %, and 10 nm thick lattice matched InGaAsP barrier with total close to 50 nm. The band-gap wavelength of quantum wells is equal to 1.65 /lm and barrier, 1.25 /lm [8]. The active zone length is close to 300 /lm and deposed on grating waveguide allowing to selecte only one wavelength: 15 50 nm at operating conditions.…”

“…To achieve the irradiation constraints specified in the test plan a preliminary proton irradiation followed by complementary gamma rays irradiation must be carried out. 8 Taking these constraints into account, we summarized in Table I, the irradiation conditions corresponding to the test plan given in figure 9. The appropriate (energy, tluence) couples have been determined using equations (8), (9) and (II).…”