[1] Jung Y, Brambilla G, Richardson D J. Optical microfiber coupler for broadband single-mode operation[J]. Optics Express, 17, 5273-5278(2009). http://europepmc.org/abstract/MED/19333292

[2] Ahmad H, Jasim A A. Fabrication and characterization of 2×2 microfiber coupler for generating two output stable multiwavelength fiber lasers[J]. Journal of Lightwave Technology, 35, 4227-4233(2017). http://ieeexplore.ieee.org/document/7994592/

[3] Hernandez-Arriaga M V, Bello-Jimenez M A, Rodriguez-Cobos A et al. . High sensitivity refractive index sensor based on highly overcoupled tapered fiber-optic couplers[J]. IEEE Sensors Journal, 17, 333-339(2017). http://ieeexplore.ieee.org/document/7744548/

[4] Sun L, Semenova Y, Wu Q et al. High sensitivity ammonia gas sensor based on a silica-gel-coated microfiber coupler[J]. Journal of Lightwave Technology, 35, 2864-2870(2017). http://ieeexplore.ieee.org/document/7920327/

[5] Pu S L, Mao L M, Yao T J et al. Microfiber coupling structures for magnetic field sensing with enhanced sensitivity[J]. IEEE Sensors Journal, 17, 5857-5861(2017). http://ieeexplore.ieee.org/document/8000298/

[6] Yan S C, Liu Z Y, Li C et al. "Hot-wire" microfluidic flowmeter based on a microfiber coupler[J]. Optics Letters, 41, 5680-5683(2016). http://www.ncbi.nlm.nih.gov/pubmed/27973488/

[7] Wei F F, Mallik A K, Liu D J et al. Magnetic field sensor based on a combination of a microfiber coupler covered with magnetic fluid and a Sagnac loop[J]. Scientific Reports, 7, 4725(2017). http://pubmedcentralcanada.ca/pmcc/articles/PMC5498580/

[8] Chen Y, Semenova Y, Farrell G et al. A compact Sagnac loop based on a microfiber coupler for twist sensing[J]. IEEE Photonics Technology Letters, 27, 2579-2582(2015). http://ieeexplore.ieee.org/document/7272084/

[9] Pu S L, Luo L F, Tang J L et al. Ultrasensitive refractive-index sensors based on tapered fiber coupler with Sagnac loop[J]. IEEE Photonics Technology Letters, 28, 1073-1076(2016). http://ieeexplore.ieee.org/document/7405273/

[10] Wang S S, Yang H J, Liao Y P et al. High-sensitivity salinity and temperature sensing in seawater based on a microfiber directional coupler[J]. IEEE Photonics Journal, 8, 6804209(2016). http://ieeexplore.ieee.org/document/7524691/

[11] Sun L, Semenova Y, Wu Q et al. Investigation of humidity and temperature response of a silica gel coated microfiber coupler[J]. IEEE Photonics Journal, 8, 6805407(2016). http://ieeexplore.ieee.org/document/7600399/

[12] Ding M, Wang P F, Brambilla G. A microfiber coupler tip thermometer[J]. Opitcs Express, 20, 5402-5408(2012). http://www.opticsinfobase.org/abstract.cfm?URI=oe-20-5-5402

[13] Wang P F, Madugani R, Zhao H Y et al. Packaged optical add-drop filter based on an optical microfiber coupler and a microsphere[J]. IEEE Photonics Technology Letters, 28, 2277-2280(2016). http://ieeexplore.ieee.org/document/7515011/

[14] Chen J H, Deng G Q, Yan S C et al. Microfiber-coupler-assisted control of wavelength tuning for Q-switched fiber laser with few-layer molybdenum disulfide nanoplates[J]. Optics Letters, 40, 3576-3579(2015).

[15] Tong L M, Lou J, Mazur E. Single-mode guiding properties of subwavelength-diameter silica and silicon wire waveguides[J]. Optics Express, 12, 1025-1035(2004). http://www.ncbi.nlm.nih.gov/pubmed/19474918

[16] Song Z Q, Yu Y, Zhang X L et al. Optical microfiber phase modulator directly driven with low-power light[J]. Chinese Optics Letters, 12, 090606(2014). http://www.opticsjournal.net/Articles/Abstract?aid=OJ140825000021MjPmSo

[17] Ma C X, Sacher W D, Tang Z Y et al. Silicon photonic transmitter for polarization-encoded quantum key distribution[J]. Optica, 3, 1274-1278(2016). http://www.opticsinfobase.org/optica/abstract.cfm?uri=optica-3-11-1274

[18] Sibson P, Erven C, Godfrey M et al. Chip-based quantum key distribution[J]. Nature Communications, 8, 13984(2017). http://www.freepatentsonline.com/y2018/0062838.html

[19] Sibson P, Kennard J E, Stanisic S et al. Integrated silicon photonics for high-speed quantum key distribution[J]. Optica, 4, 172-177(2017). http://www.opticsinfobase.org/abstract.cfm?uri=CLEO_SI-2017-JTh3E.4

[20] Birks T A, Li Y W. The shape of fiber tapers[J]. Journal of Lightwave Technology, 10, 432-438(1992). http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=134196

[21] Payne F P, Hussey C D, Yataki M S. Polarisation analysis of strongly fused and weakly fused tapered couplers[J]. Electronics Letters, 21, 561-563(1985). http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4251327

[22] Ankiewicz A, Snyder A W, Zheng X H. Coupling between parallel optical fiber cores-critical examination[J]. Journal of Lightwave Technology, 4, 1317-1323(1986). http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1074906

[23] Yu Y, Zhang X L, Xie J H et al. Investigation on fabrication and characteristics of four ports optical microfiber[J]. Chinese Journal of Lasers, 42, 0105002(2015).

[24] Davis M K. Digonnet M J F, Pantell R H. Thermal effects in doped fibers[J]. Journal of Lightwave Technology, 16, 1013-1023(1998).

[25] Digonnet M J F, Sadowski R W, Shaw H J et al. . Resonantly enhanced nonlinearity in doped fibers for low-power all-optical switching: a review[J]. Optical Fiber Technology, 3, 44-64(1997). http://www.sciencedirect.com/science/article/pii/S1068520097901899

[26] Yu Y, Qiang B, Zhang X L et al. Investigation on an all-optical intensity modulator based on an optical microfiber coupler[J]. Chinese Optics Letters, 16, 040605(2018). http://www.opticsjournal.net/Articles/Abstract?aid=OJ180410000052EaHdKg

[27] Yu Y, Zhang X L, Song Z Q et al. Precise control of the optical microfiber tapering process based on monitoring of intermodal interference[J]. Applied Optics, 53, 8222-8228(2014). http://www.ncbi.nlm.nih.gov/pubmed/25608063

[28] Ravets S, Hoffman J E, Kordell P R et al. Intermodal energy transfer in a tapered optical fiber: optimizing transmission[J]. Journal of the Optical Society of America A, 30, 2361-2371(2013). http://www.opticsinfobase.org/abstract.cfm?URI=josaa-30-11-2361