Buried-heterostructure mid-infrared quantum cascade lasers fabricated by non-selective regrowth and chemical polishing

• Published in: Electronics letters 2015-07, Vol.51 (14), p.1098-1100
• Main Authors: Chang, C.-C, Kirch, J.D, Buelow, P, Boyle, C, Kuech, T.F, Lindberg, D, Earles, T, Botez, D, Mawst, L.J
• Format: Article
• Language: English
• Subjects: Arrays; buried‐heterostructure mid‐infrared quantum cascade lasers; Chemical polishing; Coherence; continuous‐wave operation; deeply etched laser ridges; dielectric mask; Dielectrics; etched‐ridge sidewall profile; etching; fabrication method; heat dissipation; III‐V semiconductors; indium compounds; Indium phosphides; InP:Fe; iron; Lasers; metal‐organic chemical vapour deposition; MOCVD; nonselective regrowth; optical fabrication; Photonics; physical dimensions; planarisation; polishing; Quantum cascade lasers; Ridges; temperature 20 degC; wavelength 4.75 mum
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2015.1094

A novel fabrication method of buried-heterostructure (BH) mid-infrared quantum cascade lasers (QCLs) by using non-selective regrowth of iron-doped indium phosphide (InP) (Fe:InP), around deeply etched laser ridges, via metal-organic chemical vapour deposition (MOCVD) and planarisation via chemical polishing is reported. Owing to better heat dissipation, the fabricated 4.75 μm emitting QCLs exhibit about three-fold enhancement in maximum output power under continuous-wave operation at room temperature (T = 20°C) compared with that from lasers without the regrown InP. The demonstrated fabrication method provides a more flexible route to realising BH QCLs by removing strict requirements on the etched-ridge sidewall profile, as well as on the physical dimensions of the dielectric mask for the regrowth via MOCVD. The method can be further employed for making large-emitting aperture, closely packed arrays of QCLs, with planarised geometry, for coherent-power scaling.