Vernier-tuned distributed Bragg reector (VT-DBR) lasers in source swept OCT (SS-OCT) have previously been demonstrated at 1550 nm and 1600 nm.<sup>1</sup> Many OCT applications prefer 1310 nm operation. This work describes the first demonstration of a VT-DBR operating at 1310 nm in the O-band, ideal for use in SS-OCT. This paper addresses the device characterization of such lasers, illustrating they are capable of fast amplitude and frequency sweeps necessary for SS-OCT applications. Equivalent circuit models for each of the five ports are also created to determine their electrical parasitics. Narrow linewidths of the VT-DBR indicate coherence length of several centimeters are possible during fast wavelength sweeps.