In order to simplify the process, and to improve the modulation bandwidth and data transmission rate of surface emitting lasers, a vertical cavity surface emitting laser (VCSEL) with an emission wavelength of 850 nm was prepared using methods such as multi quantum well active region design, medium planarization process preparation, and oxidation constraint limitation. Low dielectric constant polyimide (PI) was used for planarization in the process, instead of the commonly used benzocyclobutene on high-speed VCSEL chips. The parasitic response of high-speed devices based on PI glue planarization process was studied. The experimental results indicate that, at low bias current, the VCSEL with 3 μm oxide aperture shows a maximum modulation bandwidth of 25.2 GHz, resonant frequency of 24.3 GHz, parasitic cutoff frequency of 13.2 GHz, modulation current efficiency factor of 22.726 GHz/mA^1/2, D factor of 19.670 GHz/mA^1/2, threshold current and differential resistance of 0.27 mA and 215.965 Ω, respectively, and maximum optical output power of 0.9 mW. The PI scheme can be used to modulate products with a bandwidth of 25 GHz and below. This result has certain guiding significance for simplifying the process and improving the data transmission rate of surface emitting lasers.