Enhancing the sensitivity of fiber Mach–Zehnder interferometers using slow and fast light

Abstract

We demonstrate theoretically and experimentally that the sensitivity of a fiber Mach-Zehnder (M-Z) interferometer can be enhanced by coupling fiber ring resonators with it. The experimental results agree well with theoretical predications that combining slow light with fast light will further increase the sensitivity of a fiber M-Z interferometer.

Enhanced spectral sensitivity of a chip-scale photonic-crystal slow-light interferometer

“…We demonstrated the increased sensitivity through a significant increase in the density of interference fringes. Enhanced-sensitvity interferometers have been an important subject of interest in the photonics community for the last ten years [1,2,[4][5][6][8][9][10][11][12][13]. We therefore believe that our experimental results are an important starting point for further studies, including onchip implementations of our device.…”

“…Our results show an enhancement of a factor of 20 in the spectral sensitivity of the interferometer, without increasing its physical size. This sensitivity is on par with that of previous implementations of material slow-light interferometers [10], using a much more compact slow light structure (the total PhC footprint is on the order of 0.015mm 2 ) [10][11][12]. In order to demonstrate the advantage of adding a slow-light medium into a spectral interferometer, we discuss the phase difference ∆φ between two light beams passing through the two arms of a MZ interferometer.…”

“…This result holds promise for compact and efficient spectrometers [1,8]. Nevertheless, up to this date, the improvement of the spectral sensitivity of interferometers has been demonstrated only in bulk optical setups, such as shearing and free-space interferometers, with highly dispersive crystals and atomic vapors [10][11][12].…”

“…Optical interferometry has benefited greatly from the use of highly dispersive materials [9][10][11][12][13]. For instance, it has been predicted that a Mach-Zehnder (MZ) interferometer with a slow-light medium in one of the arms will greatly enhance spectral sensitivity with respect to its conventional (non-slow-light) version [9][10][11].…”

Principles of Structural Slow Light and Its Applications for Optical Fiber Sensors: A Review

“…The combination of slow and fast light was placed in the M-Z interferometer signal arm to measure parameters. [34,35] The system is shown in Figure 12.…”