Open AccessLaterally coupled distributed feedback type-I quantum well cascade diode lasers emitting near 322 μm
Author(s) -
Ting Feng,
Takashi Hosoda,
L. Shterengas,
G. Kipshidze,
Aaron Stein,
Ming Lu,
Gregory Belenky
Publication year - 2017
Publication title -
applied optics
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 197
eISSN - 2155-3165
pISSN - 1559-128X
DOI - 10.1364/ao.56.000h74
Subject(s) - cascade , laser , optics , materials science , optoelectronics , diode , grating , semiconductor laser theory , distributed feedback laser , quantum well , slope efficiency , continuous wave , quantum cascade laser , tunable laser , physics , fiber laser , chemistry , chromatography
The laterally coupled distributed feedback (LC-DFB) GaSb-based type-I quantum well cascade diode lasers using the second- and the sixth-order gratings to stabilize the output spectrum near 3.22 μm were designed and fabricated. The laser heterostructure contained three cascades. The devices were manufactured using a single dry etching step defining the ∼5-μm-wide ridge with ∼5-μm-wide gratings sections adjacent to the ridge sides. The grating coupling coefficients were estimated to be about 1 cm -1 . The stability of the single-frequency operation was ensured by alignment of the DFB mode to the relatively wide gain peak. The 2-mm-long second-order LC-DFB lasers generated above 10 mW of continuous-wave (CW) output power at 20°C in epi-side-up configuration and demonstrated power conversion efficiency above 2%. The sixth-order LC-DFB lasers showed lower efficiency but still generated several milliwatts of CW output power. The devices demonstrated a CW current tuning range of about 3.5 nm at the temperature of 20°C.