GaInAsP/InP Distributed Reflector Lasers Consisting of Deeply Etched Vertical Gratings

Abstract

Deep-etching technology, which is a very simple fabrication process and requires only one lithography and one etching step without any regrowth, is applied to realize 1.5–1.55 µm wavelength GaInAsP/InP vertical grating (VG) distributed reflector (DR) lasers, which consist of a distributed feedback (DFB) region with the VG and a high-reflectivity distributed Bragg reflector (DBR) region. First, the coupling coefficient of the VG is theoretically estimated and fundamental lasing characteristics of the VG-DR lasers are investigated. Then, the fabrication process of the VG-DR lasers and the experimentally achieved fundamental lasing characteristics are given. A threshold current of 12.4 mA and a differential quantum efficiency of 42% from the front cleaved facet are achieved for a 220-µm-long and 5-µm-wide device. A submode suppression ratio (SMSR) of 33 dB at a bias current of 2.4 times the threshold is obtained.

Fabrication of all-optical switch based on intersubband transition in InGaAs/AlAsSb quantum wells with DFB structure

“…After the growth of the epitaxial layers, the DFB structure was fabricated by etching the grating that was aligned vertically with the mesa structure [9]. Initially, a waveguide with a grating pattern was fabricated by using a positive EBresist of ZEP520.…”

1.3-µm Quantum Dot Distributed Feedback Laser with Half-Etched Mesa Vertical Grating Fabricated by Cl2 Dry Etching

“…A vertical grating DFB structure fabricated by deep etching of the mesa has also been reported to eliminate the need for regrowth. [25][26][27] The advantage of this structure is that it can be aligned and etched together with the mesa through the active region in a single step. However, several problems remain regarding an optimized design for a QD laser, including the large optical scattering loss caused by fabrication fluctuation.…”

1.3 µm Distributed Feedback Laser with Half-Etching Mesa and High-Density Quantum Dots

“…The use of a simpler structure and avoidance of the need for regrowth have already been reported using a vertical grating DFB structure fabricated by deep etching mesa with quantum well. 12,13) The advantage of this structure is that it can be aligned and etched together with the mesa through the active region in a single step. In addition, the vertical grating structure enables a wide range of coupling coefficient owing to the capacity to vary the grating variation.…”