Department of Electro-Optical Engineering, National United University, Miaoli, Taiwan 360.
Opt Lett. 2010 Jun 15;35(12):2109-11. doi: 10.1364/ol.35.002109.
A differential gain-dependent phase shift between the core mode and the cladding mode can be all-optically tuned by a cw 975 nm pump light for Mach-Zehnder interferometers using two abrupt fiber tapers in a 1.2-cm-long highly Er/Yb codoped fiber. The highly doped fiber has large absorption and emission cross sections to efficiently introduce the phase shift when the inversion rate is changed by varying the pump power. The first abrupt taper converts part of core mode into the cladding mode, while the second abrupt taper recombines both modes to interfere after propagating for a length of a few millimeters.
在一段 1.2 厘米长的高掺铒/掺镱光纤中，使用两个突然变细的光纤锥，通过连续 975nm 泵浦光可以实现马赫-曾德尔干涉仪中环模和包层模之间的差分增益相关相移的全光调谐。高掺杂光纤具有较大的吸收和发射截面，当通过改变泵浦功率来改变反转率时，可以有效地引入相移。第一个突然变细的光纤锥将部分芯模转换为包层模，而第二个突然变细的光纤锥在传播几毫米后将两种模式重新组合进行干涉。
