High performance 1.55 μm InGaAsP buried-heterostructure laser diodes fabricated by single-step MOCVD regrowth and self-aligned technique

In this article, we demonstrate a simple and low-cost method to fabricate the 1.55 μm strained multiquantum-well InGaAsPInP buried-heterostructure (BH) laser diodes (LDs) by using the single-step metallorganic-chemical-vapor- deposition (MOCVD) regrowth and self-aligned technique. The active region is buried by the intrinsic InP layer which is used as the current-blocking layer as well as the electrical and optical confinement layer. The BH LDs have a calculated internal quantum efficiency of 81% and an internal loss of 21.5 cm-1. The fabricated as-cleaved BH LDs exhibit a threshold current of 6.5 mA, a maximum light output power of 21 mW at 100 mA, a maximum operating temperature of 100°C, and a characteristic temperature of 72 K in 20-60°C. The BH LDs with an as-cleaved front facet and a high reflectivity coating (∼92%) applied to the rear facet can increase the maximum operation temperature up to 125°C and have a light output power exceeding 10 mW at 80 mA and 100°C. The 3 dB frequency at a bias current of 40 mA is 8.0, 6.5, and 5.2 GHz at 30, 60, and 90°C, respectively. Besides, the 3 dB modulation bandwidth can be extended as far as 10.5 GHz at 20°C and 60 mA. These results confirm that BH LDs have the potential capacity for high-speed fiber optic applications.