Beam Combining of SOA-Based Bidirectional Tunable Fiber Nested Ring Lasers With Continuous Tunability Over the C-band at Room Temperature

Abstract

Nested ring cavities are used to develop a simple compact, low-cost semiconductor optical amplifier (SOA)-based bidirectional tunable fiber ring laser source. We propose a bidirectional tunable fiber ring laser structure based on ( N > 1) number of SOAs that has a great potential for achieving a high power laser source that uses low-power optical components by coherently coupling the nested ring cavities. A commercial tunable filter is used to deliver a wavelength tuning range of 30 nm. The lasing tunable range can be further changed by using SOAs with operating wavelengths in different regions of the optical spectrum. The output power of the bidirectional fiber ring resonator with three SOAs was around 3.5 times larger than the output of a single SOA fiber ring laser (i.e., 17.7 versus 5.14 mW) at 1550 nm wavelength. The optical signal-to-noise ratio was measured to be up to +49 dB, wavelength stability was ±0.015 nm, and optical power stability was better than ±0.2 dB.