[2] [2] YUSOFF Z,LEE J H,BELARDI W,et al.Raman effects in a highly nonlinear holey fiber:amplification and modulation[J].Optics Letters,2002,27(6):424-426.

[4] [4] BIRKS T A,KNIGHT J C,RUSSELL P S J.Endlessly single-mode photonic crystal fiber[J].Optics Letters,1997,22(13):961-963.

[5] [5] MATOS C J S D,HANSEN K P,TAYLOR J R.Experimental characterisation of Raman gain efficiency of holey fibre[J].Electronics Letters,2003,39(5):424-425.

[6] [6] FUOCHI M,POLI F,SELLERI S,et al.Study of Raman amplification properties in triangular photonic crystal fibers[J].Journal of Lightwave Technology,2003,21(10):2247-2254.

[8] [8] VENGSARKAR A M,REED W A.Dispersion-compensating single-mode fibers:efficient designs for first-and second-order compensation[J].Optics Letters,1993,18(11):924-926.

[9] [9] LEE Y S,LEE C G,KIM S.Dispersion compensating photonic crystal fiber using double-hole assisted core for high and uniform birefringence[J].Optik-International Journal for Light and Electron Optics,2017,147:334-342.

[10] [10] PRABU K,MALAVIKA R.Highly birefringent photonic crystal fiber with hybrid cladding[J].Optical Fiber Technology,2019,47:21-26.

[11] [11] PRAMANIK S,SARKAR S.Effect of dip in refractive index profile on fiber Raman gain amplifier performance[J].Optics Communications,2014,329:145-150.

[12] [12] BANDYOPADHYAY P K,SARKAR S N.Effect of sinusoidal ripples in refractive index profile distribution on the performance characteristics of dual concentric core step index fiber Raman amplifier[J].Optik-International Journal for Light and Electron Optics,2014,125(14):3679-3684.

[13] [13] WANG C C,WANG M H,WU J.Heavily germanium-doped silica fiber with a flat normal dispersion profile[J].IEEE Photonics Journal,2015,7(2):1-10.

[14] [14] FLEMING J W.Dispersion in GeO2-SiO2 glasses[J].Applied Optics,1985,23(24):4486-4493.

[16] [16] TSUJIKAWA K,TAJIMA K,OHASHI M.Rayleigh scattering reduction method for silica-based optical fiber[J].Journal of Lightwave Technology,2000,18(11):1528-1532.

[18] [18] WANG W,QU Y,ZHANG C,et al.Novel design of broadband dispersion compensating photonic crystal fiber with all solid structure and low index difference[J].Optik-International Journal for Light and Electron Optics,2017,156:279-288.

[19] [19] DAS S,DE M,SINGH V K.Single mode dispersion shifted photonic crystal fiber with liquid core for optofluidic applications[J].Optical Fiber Technology,2019,53:102012.