Uncooled (25–85°C) 10 Gbit/s operation of 1.3 [micro sign]m-range metamorphic Fabry-Perot laser on GaAs substrate

Abstract

The first direct modulation of a 1.3 mm-range metamorphic laser diode on a GaAs substrate has been realised. A 200 mm-long device had threshold currents as low as 5.2 and 11.4 mA at 25 and 858C, respectively. This laser also achieved 10 Gbit/s direct modulation up to 858C.Introduction: A 1.3 mm-range laser that can operate over a wide temperature range is an attractive light source, because it enables us to realise a low-cost module with low power consumption. The key to expanding the maximum operating temperature range is to reduce the carrier overflow from a multiple quantum well (MQW) at high temperatures. Lasers on GaAs substrates have cladding and barrier layers with large bandgaps, and this improves carrier confinement at high temperatures. Therefore, several approaches, including GaInNAs and InAs quantum dot techniques on a GaAs substrate, have been investigated with a view to realising 1.3 mm-range uncooled lasers.Another approach is to use a metamorphic buffer to lengthen the emission wavelength of an InGaAs MQW to 1.3 mm on a GaAs substrate. Metamorphic growth involves forming a buffer layer with a different lattice constant from that of the substrate by employing strain relaxation. 1.3 mm-range emissions from metamorphic InGaAs lasers have been reported [1][2][3]. In our previous study, we successfully formed a very flat and well-relaxed InGaAs layer on a GaAs substrate by using an abrupt InGaAs buffer instead of a graded buffer, and realised a laser with good static characteristics [4].In this work, we constructed a high performance short cavity FabryPerot laser with a metamorphic buffer. A highly strained InGaAsInGaAs MQW on a low indium content InGaAs buffer enables us to realise 1.3 mm-range lasing and low threshold current operation. This laser achieved a wide operating temperature range (25 -1358C) and uncooled 10 Gbit/s operation up to 858C.

InAs/In0.83Al0.17As quantum wells on GaAs substrate with type-I emission at 2.9 μm

“…[11][12][13] Comparing to InP substrate, GaAs substrate is more mature and owns the reduced cost and better mechanical robustness. GaAs-based antimony-free metamorphic lasers have been developed but limited in near-infrared (NIR) wavelength range, 14,15 Recently, MIR antimonide QW lasers have been grown on GaAs substrates using 90 interfacial misfit array (IMF) technology. 16 However, MIR emission from GaAs-based antimony-free structure has not been reported so far.…”

Low-Temperature and Metamorphic Buffer Layers

“…As a first-order approximation, the equilibrium strain is inversely proportional to the layer thickness. Despite the presence of finite residual strain, a uniform buffer can be designed with mismatch exceeding that of the device layer (compositional overshoot) so that it matches the in-plane lattice constant of the device [46]. This corresponds to 80% and 89% lattice relaxation, respectively.…”

Theory and optimisation of 1.3 and 1.55 μm (Al)InGaAs metamorphic quantum well lasers

“…the potential to monolithically integrate photonic devices with GaAs-based microelectronics -and are of lower cost than InP substrates, making the development of GaAs-based devices appealing from a commercial perspective. Recently, significant progress has been made in the development of GaAs-based • C [3], and operation at 200…”