Continuous-wave operation of distributed feedback interband cascade lasers

Abstract

Continuous-wave distributed feedback interband cascade lasers operating near 3.3 μm are reported. Single longitudinal mode emission is achieved with side mode suppression ratio greater than 30 dB at temperatures up to 175 K. A clear Bragg stop band in the laser emission spectrum indicates a dominant index coupling with the first-order grating. Detailed characteristics of these lasers are discussed.

CW, High Power, Single-Longitudinal-Mode Operation of an Optically Pumped Mid-IR DFB Laser

“…The FWHM line-width of each spectrum is about 1 nm. Several transverse modes may be present because the pump stripe is as wide as 80 μm [4,5]. High-resolution F-P interferometer measurements confirmed the SLM operation with a~1-nm spectral width.…”

“…To make it a powerful light source for spectroscopic applications, we applied a distributed-feedback (DFB) grating [2,3] to one of these lasers and achieved record high output power of more than 300 mW per facet for continuous wave (CW), single-longitudinal-mode (SLM) operation at 3.62 μm. DFB assisted CW SLM lasing has been previously demonstrated on both intersubband cascade (QC) [3,4] and interband cascade (IC) [5,6] lasers. But their powers are below 135 mW and none of them covers the 3.5-to 4.6-μm wavelength range particularly relevant to monitoring the organic compounds such as those from the Alkyne (C≡C) and Aldehyde (O=CH) groups.…”

MBE growth optimization of Sb-based interband cascade lasers

“…Due to the multitude of adjustable parameters in MBE growth that could affect device performance, we have first focused our effort on obtaining a high degree of crystalline quality and surface smoothness. This has allowed for the deposition of over 8 mm of strain-balanced epitaxial material with excellent crystalline quality, and facilitated the fabrication of distributed feedback IC lasers [8] with smooth surfaces. The MBE growth optimization has generally facilitated the demonstration of mid-infrared electrically pumped laser diodes with record-breaking performance (such as high cw operating temperature and threshold current densities).…”

“…Since this type of laser combines the advantages of quantum cascade (QC) lasers [2] and type-II quantum well interband lasers, type-II IC lasers were projected by simulations [3,4] to operate in continuous wave (cw) mode up to room temperature with high output power. While significant advances toward such a high-performance level have been reported [5][6][7][8][9], the optimization of the growth and fabrication parameters for these new devices is an ongoing effort. The growth by molecular beam epitaxy (MBE) of these laser structures can take over 20 h to complete, with over 8 mm of strained superlattice and multi-QW material comprising the epitaxial layer.…”

Trace gas measurements using optically resonant cavities and quantum cascade lasers operating at room temperature

“…[30][31][32] It was possible to detect CO but clearly the technique suffered from low laser intensity. Recent advances in semiconductor laser technology, in particular, the advent of intersubband quantum cascade lasers ͑QCLs͒ and interband cascade lasers ͑ICLs͒, [33][34][35][36] provides new possibilities for highly sensitive and selective trace gas detection using MIR absorption spectroscopy 1, [37][38][39][40][41][42][43][44] and enabled sensitivities of 5 ϫ 10 −10 cm −1 Hz −1/2 to be accomplished but at the expense of large sample volumes. 39 Distributed feedback ͑DFB͒-QCLs combine single-frequency operation with tunability over several wavenumbers, and average powers over a milliwatt; hence they are superior to lead salt lasers.…”