High power and broad spectrum GaSb-based 2.1 μm superluminescent diode with advanced cascade cavity suppression waveguide

We demonstrate a high-power and broad-spectrum GaSb-based superluminescent diode (SLD) emitting around 2.1 μm with an advanced cascade cavity suppression (ACCS) waveguide geometry, where the most appropriate combination of the ACCS waveguide geometry was identified through optimizing the mode distribution overlap integral of different curved radii and tilt angles of SLD's waveguide geometry. The SLD performs an exceptional single-transverse-mode optical output power of up to 300 mW at room temperature (RT) under the continuous wave (CW) operation and a broad spectrum with a full width at half maximum (FWHM) of 90 nm and a 15°FWHM divergence angle. The emitting structure, grown by molecular beam epitaxy (MBE) technique, consists of two compressively strained InGaSb/AlGaAsSb type-I quantum wells, which ensures superior optical output power. An ultra-low antireflection (UAR) coating was employed with the ACCS waveguide to achieve its amplified spontaneous emission (ASE) and prevent the potential of lasing. Above all, the high power, broad spectrum, and high-quality light source can satisfy demands for mid-wave infrared (MWIR) heterogeneous integration with photonic integrated circuits for spectroscopic sensing and address the need for coupling to external cavity elements with silicon waveguides to achieve further applications.