In this study, we have investigated Gunn oscillations in an InGaAs- based light emitter that originates from domain transition along the device. InGaAs epilayers were grown were grown by the Metal Organic Vapor Phase Epitaxy (MOVPE) with an alloy composition on %In =0.53. To fabricate the Gunn light emitter, the samples was defined in a simple bar geometry with various channel lengths. High speed Current-Voltage (I-V) were performed to avoid ohmic heating (Joule heating) to define the threshold of negative differential resistance regime and observe Gunn oscillations at the onset of the NDR. Integrated Electroluminescence measurements were carried to determine the threshold the light emission and EL measurements were used to obtain spectrum of the emission at NDR threshold. Gunn oscillations are observed just above NDR threshold of the I-V curves at around 3 kV/cm for InGaAs-based Gunn devices at 300K. The amplitude and period of the Gunn oscillations are observed to be electric-field dependent. Electrical measurements were made at 20ns, 40ns and 60ns pulse width of applied voltage. From the beginning of the NDR, Gunn oscillations have observed with a frequency of approximately between 0,5 GHz and 1GHz depending on the electric field. IEL signal has been started at around 3kV/cm then drastically increased. The peak wavelength of EL is observed to be at 1600 nm