C-band continuously tunable lasers using tunable fiber Bragg gratings

doi:10.1016/j.optlastec.2006.08.007

Optics & Laser Technology

Volume 39, Issue 6, September 2007, Pages 1214-1217

https://doi.org/10.1016/j.optlastec.2006.08.007 Get rights and content

Abstract

We report the development of a ring tunable fiber laser based on tunable fiber Bragg gratings (TFBG) integrated with an optical circulator. The TFBG is embedded inside a 3-piont bending device for wavelength tuning. The tunable laser operating in the C-band has power variation, tuning resolution, tuning range and laser line width of ±0.5 dB, 0.5 nm, 25.0 nm and less than 0.05 nm, respectively. As 40 mW of pump power is used, the ring tunable laser has a side mode suppression ratio of 60 dB and a power conversion efficiency of 25%. These specifications ensure the high-quality operation of a tunable laser.

Introduction

In recent years, lasers have found a variety of applications, including sensing, instrument testing, optical signal processing, optical communications, and photon analog-to-digital conversion (ADC) [1], [2]. More specifically, tunable lasers have been flexible for usage in wavelength routing, wavelength protection and optical measurement. Several methods have already been proposed to investigate tunable lasers using photonic crystal mirrors [3] and a multiple quantum-well waveguide. Among them, the use of the erbium-doped fiber ring laser (EDFRL) exhibits potential for success, partially since it features a low-temperature sensitivity of wavelength. The selection of their operation wavelengths has been achieved by using different optical filtering devices, such as Mach–Zehnder filters or in-fiber comb filters. However, the tuning range can be narrow [4], or the line width can be wide due to large filter bandwidth. Another approach is the dual wavelength tunable fiber laser. Lasing occurs at two different wavelengths, alternatively, by using a circuit consisting of two overlapping circuits with a common gain medium [5]. In this paper, we demonstrate the use of the tunable fiber-Bragg-gratings (TFBGs)-based tunable laser. A suitably designed optical device could cover the whole C-band region. The laser is constructed by a 1×2 optical switch (OSW) and optical circulator (OC). The results show that the tuning ability could be realized by appropriately switching the OSW and compressing/straining the TFBGs.

Section snippets

Operation mechanism of the TFBG

From the theory of solid mechanics [6], the transverse displacement (ν) is related to longitudinal strain (ε) applied to the FBG for tuning purpose. $E ε = \frac{My}{I}$ and $ν = \frac{- P L^{3}}{48 EI} .$ In these equations, E is the elastic modulus, I is the moment of inertia, M(=PL/2) is the bending moment, P is the load, L is the span of the 3-point bending support, and y is the distance to the point at which the bending strain is desired, which is measured from the neutral axis. Thus, from Eqs (1), (2), we realize the

Configuration description of the TFBG laser

Fig. 3 shows the proposed scheme of the wavelength tunable laser. This circuit includes 10 m of EDF, a wavelength division multiplexing (WDM) coupler, and a 1480 nm pumping source operating at 40 mW. The 3-port OC integrates with the FBGs, which act as reflective mirrors to form a looped-back circuit. On the right hand side, there is one 1×2 OSW and two TFBGs (TFBG₁, TFBG₂) connected to either output port of the OSW. By compressing or straining these TFBGs, their overlapping spectra could cover

Experimental results and discussion

Fig. 4 shows superimposed optical spectra of the ring tunable laser with a side mode suppression ratio (SMSR) of 60 dB. It could cover the C-band window using the combined TFBGs, with tuning resolution of 0.5 nm for each TFBG. The output power increases as the reflectivity is increased. The average output power is 0.0 dBm (i.e., 1 mW) for each channel and power variation is less than ±0.5 dB over the whole tuning range. Thus, no variable optical attenuator (VOA) is need for power equalization laser

Conclusion

We report the investigation of the ring tunable laser based on TFBG technology. Each TFBG is embedded inside a 3-point bending device for wavelength tuning. The power variation, tuning resolution, tuning range and laser line width are 0.5 dB, 0.5, 25 nm and less than 0.05 nm, respectively. The ring tunable laser also has 60 dB of SMSR to ensure high-quality operation. With the features mentioned above, the tunable laser is a potential candidate for high-speed modulation in either a digital or

Acknowledgments

The work is partially supported by NSC under projects No. 94-2219-E-011-007 and 94-2622-E-011-021-CC3, Taiwan, ROC. We thank Y.C. Lai, S.C Chen and C.R. Wang for their kind help.

References (8)

Y.J. Rao
Recent process in applications of in-fibre Bragg grating sensors
Opt Lasers Eng
(1999)
S.K. Liaw et al.
Parallel pump-shared linear cavity laser array using 980-nm pump reflectors or N pieces of gain fibers as self-equalizers
IEEE Photonic Technol Lett
(2000)
S.K. Liaw et al.
Wavelength tuning and multiple-wavelength array-waveguide-grating lasers
Opt Eng
(2003)
H.X. Chen et al.
Widely tunable single-frequency erbium-doped fiber lasers
IEEE Photonic Technol Lett
(2003)

There are more references available in the full text version of this article.

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Citation Excerpt :
To achieve single longitudinal mode (SLM) and stable laser output several approaches have been proposed in the literature. These techniques are based on conventional ring laser configuration with different all-fiber-filters such as fiber Bragg gratings (FBG) [10,11], tapered fibers [12], Fabry-Perot (FP) filters [13] and multimode fibers (MMFs) [14], multiple fiber ring structures [15], saturable absorbers (SAs) with unpumped doped fibers [16]. Since these fiber filters such as FBGs or tapered fibers can be tuned through an applied strain or heating, all-fiber filter based ring lasers come with difficulties for packaging.
This study presents two novel tunable erbium doped fiber ring laser (EDFRL) configurations based on loop EDFA design and double-pass EDFA design, respectively to achieve an ultra-wideband tuning range and stable single-longitudinal-mode lasing operation. A micro-electro-mechanical system (MEMS) based optical tunable band pass filter was utilized as the wavelength selection element. Output spectral and power characteristics of these EDFRLs were experimentally analyzed and discussed. The EDFRLs had moderate and stable output power level ( $~$ -3 dBm) over 70 nm tuning range that covers C+L band. Moreover, the proposed EDFRLs could also suppress the undesired multi-longitudinal-modes successfully and have a high ( $~$ 60 dB) OSNR level in whole tuning range.
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C-band continuously tunable lasers using tunable fiber Bragg gratings

Abstract

Introduction

Section snippets

Operation mechanism of the TFBG

Configuration description of the TFBG laser

Experimental results and discussion

Conclusion

Acknowledgments

Opt Lasers Eng

Parallel pump-shared linear cavity laser array using 980-nm pump reflectors or N pieces of gain fibers as self-equalizers

IEEE Photonic Technol Lett

Wavelength tuning and multiple-wavelength array-waveguide-grating lasers

Opt Eng

Widely tunable single-frequency erbium-doped fiber lasers

IEEE Photonic Technol Lett