Bulk-Micromachined VCSEL At 1.55 $\mu$m With 76-nm Single-Mode Continuous Tuning Range

A single-mode continuous tuning range of 76 nm is realized using a bulk-micromachined vertical-cavity surface-emitting laser (VCSEL) operating at wavelengths around 1.55 $\mu$m. The bulk-micromachined upper mirror is optimized for dielectric material and manufactured separately from the half-VCSEL. The VCSEL is tuned by an electrothermal actuation of a concave bended membrane. The tuning range characteristics in dependence on the bias of the VCSEL are investigated. It is determined that the tuning range saturates by increasing the current of the VCSEL and a further increase causes a multimode behavior within the tuning range.