Dual wavelength single longitudinal mode Ytterbium-doped fiber laser using a dual-tapered Mach-Zehnder interferometer

H Ahmad,M A M Salim,S W Harun,S R Azzuhri,M Z Zulkifli

doi:10.2971/jeos.2015.15013

Abstract

This paper describes a dual wavelength single longitudinal mode (SLM) demonstration for a proposed ytterbium-doped fiber laser. A dualtapered Mach-Zehnder interferometer (MZI) was inserted into the laser ring cavity setup to ensure a stable dual wavelength and SLM operation. The consequent dual wavelength lasing operation had a wavelength spacing of 0.94 nm and a side mode suppression ratio (SMSR) of 50 dB, with the linewidth of this setup measured as 294.15 kHz. A stability test allowed for a measurement of max power fluctuation as less than 0.8 dB for each wavelength and which was indicative of a stable dual wavelength operation.

Highlights

Development of dual wavelength fiber lasers (DWFLs) has gained much attention in recent years due to the needs of applications such as photonic generation of microwave carriers [1], microwave photonic filters [2] and high-bit-rate soliton pulses [3], that can only be satisfied by DWFLs
The output of the isolator was subsequently connected to a polarization controller (PC) that controlled the cavity state of polarization, and the PC output was attached to the dualtapered Mach-Zehnder interferometer (MZI) fiber, which was in turn connected to a 90/10 fused bi-conical optical coupler
This paper describes in detail a successful demonstration of a dual wavelength generation and single longitudinal mode (SLM) operation utilizing ytterbium-doped fiber (YDF) and a dual-tapered fiber MZI filter

Summary

Introduction

Development of dual wavelength fiber lasers (DWFLs) has gained much attention in recent years due to the needs of applications such as photonic generation of microwave carriers [1], microwave photonic filters [2] and high-bit-rate soliton pulses [3], that can only be satisfied by DWFLs. Dual and multiwavelength output for YDF reported so far has operated under multimode oscillation and mode hopping [9, 10] and as such has a severe disadvantage within applications such as optical coherence tomography (OCT) [14] that require a superior coherence and optical properties possessing extremely low noise. Such requirements are only achievable via single longitudinal mode (SLM) operation. A high level of interest exists for dual wavelength SLM operation involving YDF due to potential applications in optical communication and optical sensing in the 1 μm region

Methods

Results

Conclusion