title: High-accuracy wavelength-change measurement system based on a Wollaston interferometer, incorporating a self-referencing scheme.
abstract: A novel wavelength-difference measurement scheme with a Wollaston prism is presented. By using a suitable reference wavelength, a small variation in the signal wavelength can be converted into a relatively larger change in the modulated wavelength, as a result of the so-called fringe beating effect, resulting in enhanced measurement sensitivity by use of autocorrelation and Gaussian filtering techniques. From the results of a simulation carried out, we observed a wavelength variation of 0.01 nm over 15 nm or 0.1 nm over 60 nm for a typical pair of laser diodes with wavelengths of 785 and 810 nm, and wavelength variations of 0.5 nm over 40 nm or 1 nm over 110 nm for 671-and 785-nm wavelengths. These results were partially verified by the experimental results obtained for which a resolution of 0.01 nm over a range of 2.5 nm for the first pair and 0.5 nm over 4 nm for the second pair of laser diodes was seen. The results have applications to the determination of wavelength variations in a wavelength-division multiplexing system or measurement of the wavelength changes induced in a range of optical sensors.
authors.forename: X Q
authors.initials: XQ
authors.lastname: Jiang
authors.forename: J
authors.initials: J
authors.lastname: Kemp
authors.forename: Y N
authors.initials: YN
authors.lastname: Ning
authors.forename: A W
authors.initials: AW
authors.lastname: Palmer
authors.forename: K T
authors.initials: KT
authors.lastname: Grattan