1W fiber output operation at 35 degree C of FBG-laser with a GaInAsP laser chip with electric field control layer for fiber Raman amplifier

In recent digital coherent transmission systems, it is necessary to improve the received Optical Signal to Noise Ratio (OSNR) after fiber transmission in order to achieve higher transmission capacity. Fiber Raman Amplifiers (FRAs) are well-known techniques for improving OSNR, especially backward FRAs, which are widely applied in high-capacity digital coherent transmission systems. However, pump lasers having higher output and lower power consumption are required since the Raman gain is small in the FRAs. As a means to realize these characteristics, a laser waveguide structure with a small optical confinement coefficient of the LD chip (low-Γ structure) is very effective. Especially, this makes Inter-Valence Band Absorption (IVBA) could be reduced by distributing an electric field toward the substrate side, and internal loss could be reduced to improve the slope efficiency. We have proposed a novel low-Γ structure consisting of a GaInAsP/InP electric field-controlled layer, which has an advantage of mass production. In this paper, we demonstrate 1W fiber output operation at 35 °C of Fiber-Bragg grating laser modules (FBG-lasers) for Fiber Raman Amplifier using a GaInAsP laser chip with electric field control layer for the first time. In order to realize high power at high temperature operation of 35 °C of laser chip temperature at a case temperature of 70 °C, we optimize the design of a laser chip waveguide keeping a single transverse mode to reduce the series resistance. With an operating current of 2.7 A, FBG-laser exhibits 7.8W of power consumption with 775mW of fiber output.