Directly Modulated Tunable Single-Mode Lasers Based on a Coupled Microcavity

In this work, we investigate an alternative directly modulated laser solution with applications to multiwavelength 25 Gb/s systems. The presented solution is based on a hybrid square/rhombus-rectangular laser (HSRRL), which consists of a Fabry-Perot (FP) cavity and a square/rhombus microcavity (SRM). This structure is implemented and demonstrates single-mode lasing over a wide wavelength tuning range (30.8 nm). Single-mode operation is achieved with a side-mode suppression ratio (SMSR) greater than 30 dB and a linewidth of 10 MHz. Furthermore, with an electrical 3 dB bandwidth of 10 GHz. It is possible to directly modulate at 25 Gb/s with promising performance. These devices are simple and they are expected to meet the cost and power requirements of current networks.