Narrow linewidth tunable V-cavity laser using self-injection method

A widely tunable V-cavity semiconductor laser with kilohertz linewidth is demonstrated using simple self-injection method. The tunable laser is packaged into a small-form-factor 9-pin TOSA and can be tuned over 22 channels at 100 GHz spacing with side mode suppression ratios over 36 dB. Self-injection method is used for linewidth reduction by applying optical feedback. Linewidth of the V-cavity laser can be compressed from several megahertz to tens of kilohertz. The linewidth reduction method is essentially channel independent and can be easily realized. It can meet the requirements of many applications such as high-order modulation, coherent communication and sensing.