High-power 1300 nm FDML swept laser using polygon-based narrowband optical scanning filter

Abstract

Swept-source optical coherence tomography (SS-OCT) has received much attention in recent years because of its higher sensitivity in high speed imaging. A fast and high powered wavelength-swept laser is important for SS-OCT since its speed and sensitivity directly rely on the sweeping rate and the output power of the swept laser. Much progress has been made on the development of high-speed swept lasers, but their output power has been limited. We present a Fourierdomain mode-locked 1300 nm wavelength-swept laser that uses a polygon-based narrowband optical scanning filter and a high-efficiency semiconductor optical amplifier. The optical filter and laser structure were designed and constructed for an optimized optical power output. Average output powers of 71 mW has been achieved without an external amplifier, while the wavelength is swept continuously from 1247 nm to 1360 nm. A unidirectional wavelength sweeping rate of 7452 nm/ms (65.95 kHz repetition rate) was achieved by using a 72 facet polygon scanner with a rotation rate of 916 revolutions per second. The instantaneous linewidth of this laser is 0.09 nm, which corresponds to a coherence length of 16 mm. This laser is most suitable for optical coherence tomography applications.