Broadly tunable vertical‐coupler filtered tensile‐strained InGaAs/InGaAsP multiple quantum well laser

Using tensile‐strained InGaAs/InGaAsP multiple quantum well material to increase the gain bandwidth, we demonstrate a tuning range of 74.4 nm with sidemode‐suppression ratio of ≳25 dB and as high as 34 dB in a broadly tunable vertical‐coupler filtered laser at 1.55 μm. Due to its wide gain bandwidth and significant gain‐peak shift to shorter wavelengths with gain current increase, the tensile‐strained quantum well material is well suited for broadly tunable lasers.