Baojin Peng

Bending analysis of a dual-core photonic crystal fiber

A dual-core photonic crystal flber (DC-PCF) is proposed, and bending characteristics of the DC-PCF are investigated. Two flber cores are employed in the cross-section of the DC-PCF, which result in a mode coupling between the two flber cores when the light propagates inside the DC-PCF. The mode coupling between two flber cores of the DC-PCF is sensitive to the directional bending of the DC-PCF which essentially provides a method to achieve bending sensing. A DC-PCF-based bending sensor is proposed by injecting a broadband light into one flber core of the DC-PCF on one side and detecting output spectrum from another flber core of the DC-PCF on the other side. In our simulations, a parabola curve which shows the relationship between the wavelength shift of the transmission spectrum of the DC- PCF-based bending sensor and the bending curvature of the DC-PCF is presented.

All-fiber refractometer based on core mismatch structure

We demonstrate a novel all-fiber refractometer which is a multimode-single mode-multimode (MM-SM-MM) fiber structure formed by splicing a section of uncoated single mode fiber (SMF) with two short sections of multimode fibers (MMFs). Owing to the core mismatch at the splicing points of the SMF with two sections of MMFs, part of the guided light propagates in the cladding of the SMF, which makes the SMF sensitive to the external refractive index (RI). RI sensing is achieved by measuring the wavelength shift of the interference pattern of the cladding mode and the core mode of the SMF. A RI sensor with an average sensitivity of 412 nm/RUI (refractive index unit) for a RI range from 1.333 to 1.400 is presented.

A novel method for detecting melamine in pure milk

The fluorescence spectra of melamine-contained milk solution excited by the exciting light have been experimentally studied in this paper. The experiments show that the melamine-contained milk solution can produce strong fluorescence when excited by 467nm exciting light. The fluorescence spectrum peak is around 540nm and the fluorescence intensity would increase firstly and then decrease with the increasing concentration of melamine in pure milk. Based on this result, combining with the optical technology and computer technology, a simple detection system device has been designed. The device can quickly detect whether the milk containing melamine in real-time and accurately show the concentration of melamine in a certain range, which make the device have strong practicability.