Theory and experiment of a fiber loop mirror filter of two-stage polarization-maintaining fibers and polarization controllers for multiwavelength fiber ring laser

Wang, Jing; Zheng, Kai; Peng, Jian; Liu, Lisong; Li, Jian; Jian, Shuisheng

doi:10.1364/oe.17.010573

Cited by 44 publications

(23 citation statements)

References 16 publications

(22 reference statements)

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“…High-order loop mirror filter that consists of more than one piece of high-birefringent fiber has been used for generating optical comb filters with unique comb profiles for various signal processing tasks [40][41][42]. With careful design, the high-order comb profile can be used as a spectral slicer for generating multi-wavelength optical carrier with multiple interleaved combs.…”

Section: Three-passband Microwave Photonic Filtermentioning

confidence: 99%

Tunable Multiband Microwave Photonic Filters

Fok

2017

Photonics

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Abstract:The increasing demand for multifunctional devices, the use of cognitive wireless technology to solve the frequency resource shortage problem, as well as the capabilities and operational flexibility necessary to meet ever-changing environment result in an urgent need of multiband wireless communications. Spectral filter is an essential part of any communication systems, and in the case of multiband wireless communications, tunable multiband RF filters are required for channel selection, noise/interference removal, and RF signal processing. Unfortunately, it is difficult for RF electronics to achieve both tunable and multiband spectral filtering. Recent advancements of microwave photonics have proven itself to be a promising candidate to solve various challenges in RF electronics including spectral filtering, however, the development of multiband microwave photonic filtering still faces lots of difficulties, due to the limited scalability and tunability of existing microwave photonic schemes. In this review paper, we first discuss the challenges that were facing by multiband microwave photonic filter, then we review recent techniques that have been developed to tackle the challenge and lead to promising developments of tunable microwave photonic multiband filters. The successful design and implementation of tunable microwave photonic multiband filter facilitate the vision of dynamic multiband wireless communications and radio frequency signal processing for commercial, defense, and civilian applications.

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Section: Three-passband Microwave Photonic Filtermentioning

confidence: 99%

Tunable Multiband Microwave Photonic Filters

Fok

2017

Photonics

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“…The comb filter which was based on the Sagnac loop filter (SLF) had been used extensively in the design of MWFL [12][13][14]. SLF is popular to be used for various applications due to its simple structure and output variability which can simply be done by varying the PC and PMF parameter [15][16][17]. Tuning characteristic is a desired feature of any comb filter when it is used in a multiwavelength light source.…”

Section: Theoretical Analysis Of a Two-stage Sagnac Loop Filter Usingmentioning

confidence: 99%

“…The two lights contrarily pass through the PCs and PMFs before reentering the 3dB coupler and transmitted out through port 2. The polarization state of the CW and CCW travelling lights in this work was analyzed using Jones matrix [17] which can describe efficiently the polarization state of a plane wave.…”

Section: Theoretical and Operating Principlementioning

confidence: 99%

Theoretical Analysis of a Two-stage Sagnac loop filter using Jones Matrices

Ahmad¹,

Dahlan²,

Cholan³

2017

IJECE

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In this work, a theoretical analysis of a Sagnac loop filter (SLF) with twostage polarization maintaining fibers (PMFs) and polarization controllers (PCs) is presented. The transmission function of this two-stage SLF is calculated in detail by using Jones matrix. The calculation is performed in order to investigate the filtering characteristics. The theoretical results show that the wavelength interval is depending on the dynamic settings of the length of the PMFs and the polarization angle of the PCs. By changing the polarization angle of the PCs, a multiple of single, dual or triple wavelength in each channel can be achieved. Based on this study, a flat multiwavelength spectrum can be obtained by adjusting the PMFs and the PCs in the twostage SLF. This finding significantly contributes to the generation of multiwavelength fiber laser (MWFL) that can be used for many optical applications. Keyword:Multiwavelength fiber laser Optical fiber Polarization controller (PC) Polarization maintaining fiber Sagnac loop filter (SLF)

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“…The incident light is split into c1ockwise and counterclockwise beams by the coupler, and the two beams pass through the PC and the Hi-Bi microfibers from opposite directions. The transmitted (T) and reflected (R) outputs may be expressed as [12] T cos…”

mentioning

confidence: 99%

“…Compared with FLM comb filters made from conventional Hi-Bi fibers [12], the current devices need very short length of microfibers and the transmission/reflection spectra may be tuned by varying the RI surrounding the microfiber. The sensitivity of dip-wavelength to the RI was measured to be ∼2 × 10 4 nm∕RIU.…”

mentioning

confidence: 99%

Tunable comb filters and refractive index sensors based on fiber loop mirror with inline high birefringence microfiber

et al. 2013

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Highly birefringent (Hi-Bi) microfiber-based fiber loop mirrors (FLMs) were studied for tunable comb filters and refractive index (RI) sensors. The use of two cascaded Hi-Bi microfibers instead of a single microfiber allows more flexibility in controlling the transmission/reflection characteristics of the FLM. The length of Hi-Bi microfibers is of the order of centimeters, one or even more than two orders of magnitude shorter than the conventional Hi-Bi fiber-based FLM devices. The transmission/reflection spectra are sensitive to the RI surrounding the microfibers, and RI sensitivity of 20 Optical comb filters as multichannel filters have been studied intensively for application in wavelength division multiplexing (WDM) communication systems [7], and filters with flattop are particularly attractive for DWDM systems due to signal fidelity and tolerance of signal wavelength drift. Especially, all-fiber comb filters based on a Sagnac fiber loop mirror (FLM) are popularly used for all-optical signal processing and multiwavelength fiber lasers [8][9][10] due to lower insertion loss and better performance.In this Letter, we investigate the use of highly birefringent (Hi-Bi) microfiber-based FLMs for tunable comb filters and high sensitivity refractive index (RI) sensors. Two different configurations are studied. One incorporates a single piece of twisted Hi-Bi microfiber in a Sagnac loop, while the other includes two pieces of Hi-Bi microfibers cascaded along a fiber with a rotation of their birefringence axes. This work on microfibers may result in novel applications, such as wavelengthscale light transmission and interconnection, which are useful for photonic integration, computing, and nanoscale sensing.The Hi-Bi microfiber is made from a commercial SMF-28 (outer diameter D ∼ 125 μm, core diameter d ∼ 8.2 μm, Δn ∼ 0.36%) [11]. The SMF-28 fiber is first "processed" by use of a femtosecond IR laser system (Fig. 1) to cutting away parts of the silica cladding on opposite sides of the SMF, resulting in an approximately square-like cross section [inset (a) in Fig. 1]. Figure 2 shows photos of a "processed" SMF with a cutting away depth of ∼26 μm, and a length of ∼3 mm. The "processed" SMF is then taper-drawn to micrometer size by use of a flame-brushing technique. The cross-sectional shape of the "processed" region is well preserved during the initial taper-drawn process and eventually turns to an approximately elliptical shape when the fiber diameter is reduced down to wavelength scale, which generates a high birefringence of the order of 10 −2 [11], much bigger than conventional polarization maintaining fibers. The insertion loss of the tapered microfibers with diameter above 2 μm is in general considerably smaller than 0.2 dB. The ellipticity depends on the depth of the cut and the parameters used in the tapering process.To fabricate two cascaded Hi-Bi microfibers along the same SMF, the SMF is first cut at one location and the Fig. 1. Schematic of the femtosecond IR laser system. Insets: artistic view of the idealiz...

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Theory and experiment of a fiber loop mirror filter of two-stage polarization-maintaining fibers and polarization controllers for multiwavelength fiber ring laser

Cited by 44 publications

References 16 publications

Tunable Multiband Microwave Photonic Filters

Tunable Multiband Microwave Photonic Filters

Theoretical Analysis of a Two-stage Sagnac loop filter using Jones Matrices

Tunable comb filters and refractive index sensors based on fiber loop mirror with inline high birefringence microfiber

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