Abstract: A sensing fiber adapted to transmit a sensing light along a path and sense an object is provided. The fiber includes a core, a plurality of photonic crystal structures surrounding the core, a sensing surface and a metal sensing layer. The core is located at the center of the fiber. The photonic crystal structures extend along the path. The sensing surface extends along part of the path and adjacent to the core, and the metal sensing layer having a plurality of metal grating structure is disposed on the sensing surface. When the fiber is sensing the object, the metal sensing layer is located between the sensing surface and the object, and part of the sensing light will be converted into a signal light by the object on the metal sensor layer. A sensing device is also provided.

Abstract: An optical fiber communication method includes the steps of: providing an optical fiber that includes a core, and a second-order Bragg grating structure formed on the core; and emitting a data-carrying optical signal to an outer peripheral surface of the optical fiber that corresponds to the second-order Bragg grating structure in a radial direction of the optical fiber, so that the data-carrying optical signal is coupled into the core of the optical fiber via the second-order Bragg grating structure for transmission therein.

Abstract: A method of generating an optical radiation signal is to be implemented by an optical radiation signal generating device including a dual beam generating unit for receiving an original optical input signal, and a second-order fiber Bragg grating (FBG). The dual-beam generating unit is configured to generate, from the original optical input signal, first and second optical input signals having a phase difference therebetween. The second-order FBG is configured to receive the first and second optical input signals, and to radiate an optical radiation signal by interference between the first and second optical input signals.

Abstract: A method of generating an optical radiation signal is to be implemented by an optical radiation signal generating device including a dual beam generating unit for receiving an original optical input signal, and a second-order fiber Bragg grating (FBG). The dual-beam generating unit is configured to generate, from the original optical input signal, first and second optical input signals having a phase difference therebetween. The second-order FBG is configured to receive the first and second optical input signals, and to radiate an optical radiation signal by interference between the first and second optical input signals.

Abstract: An optical fiber communication method for communication between a transmitting terminal and a receiving terminal includes the steps of: providing an optical fiber to be coupled to the transmitting terminal and including a core that is provided with at least one second-order Bragg grating structure and a cladding that surrounds the core; configuring the transmitting terminal to output a data-carrying optical signal to one end of the core of the optical fiber for subsequent wireless transmission of the data-carrying optical signal via radiation through the second-order Bragg grating structure of the optical fiber; and configuring the receiving terminal to receive the signal radiated by the second-order Bragg grating structure of the optical fiber. A transmitting device is also disclosed.

Abstract: A light extracting device includes a dual light generating unit and a first order Bragg grating unit. The dual light generating unit is for receiving an input optical signal and a control signal, and for generating from the input optical signal first and second optical signals that have a phase difference there between. The phase difference is associated with the control signal. The first order Bragg grating unit is for receiving the first and second optical signals from the dual light generating unit, and for causing optical interference to occur between the first and second optical signals within a predetermined wavelength range to result in first and second output optical signals.

Abstract: A light extracting device includes a dual light generating unit and a first order Bragg grating unit. The dual light generating unit is for receiving an input optical signal and a control signal, and for generating from the input optical signal first and second optical signals that have a phase difference there between. The phase difference is associated with the control signal. The first order Bragg grating unit is for receiving the first and second optical signals from the dual light generating unit, and for causing optical interference to occur between the first and second optical signals within a predetermined wavelength range to result in first and second output optical signals.

Abstract: An optical fiber communication method for communication between a transmitting terminal and a receiving terminal includes the steps of: providing an optical fiber to be coupled to the transmitting terminal and including a core that is provided with at least one second-order Bragg grating structure and a cladding that surrounds the core; configuring the transmitting terminal to output a data-carrying optical signal to one end of the core of the optical fiber for subsequent wireless transmission of the data-carrying optical signal via radiation through the second-order Bragg grating structure of the optical fiber; and configuring the receiving terminal to receive the signal radiated by the second-order Bragg grating structure of the optical fiber. A transmitting device is also disclosed.

Abstract: A fiber-optic switchable wavelength filter comprises a fiber grating positioned in the thin section of the fiber, a horn with the tip attached to the side of the fiber, and a piezoelectric transducer fixed to the bottom of the horn. Upon receiving a voltage signal, the piezoelectric transducer can create acoustic wave in the horn, wherein the amplitude of the acoustic vibration in the horn is controlled by the magnitude of the voltage signal. The vibration energy is transferred and focused from the horn to the fiber, such that the operation wavelength is switched by changing the reflectivity of the optical signal at the Bragg wavelength and the reflectivity of the optical signal at the cladding-mode coupling wavelength.

Abstract: A reflectivity-tunable fiber reflector is disclosed. The Bragg reflectivity of the fiber grating is modulated by exciting the transverse vibration of the fiber through an acoustic wave. The excitation of the transverse vibration, leading to fiber grating tilting and fiber micro-bending, induces the coupling of the fiber core mode into cladding modes. This leads to the reduction of core-mode power and hence that of Bragg reflection. This mechanism is applied by this invention to control the reflectivity of a fiber optic Bragg grating after fabrication. The fiber reflector is suitable for fiber-compatible acousto-optical switching.