The present invention is based on a two-dimensional photonic crystal where are inserted defects that originate two waveguides and one resonant cavity. An electromagnetic signal that crosses the device is confined in the interior of the defects, due to the photonic band gap associated with the periodic structure that surrounds it. Its main function is the control of the flux of an electromagnetic signal over a communication channel, blocking (state off) or allowing (state on) the passage of the signal. It also promotes the change in the propagation direction of an electromagnetic signal by an angle of 120 degrees, providing greater flexibility in the design of integrated optical systems. The working principle of the device is based on the excitation of dipole modes in its resonant cavity, accordingly to the application of an external DC magnetic field on the magneto-optical material that constitutes it. In states on and off the magneto-optical material is magnetized and nonmagnetized, respectively.

An optical isolator 10 according to the present disclosure includes a substrate 11 and an optical waveguide 12 provided on the substrate 11. The optical waveguide 12 includes a first end part 13, a plurality of second end parts 14 arranged in an array, and at least one branching part 18 located between the first end part 13 and the plurality of second end parts 14. The optical waveguide 12 has a portion having non-reciprocity and gives different non-reciprocal phase shift amounts between the first end part 13 and at least two of the second end parts 14.

A display device according to the present invention is a light stippling display device that performs light stippling. In the device, a plurality of hole portions are formed on a display plate portion including a magnetized sheet which is magnetized on both sides, and the hole portion is opened and closed by a light shielding body made of a magnetic ball. Thereby, the position of the light shielding body is switched between a light transmitting state and a light shielding state. The light shielding body has directivity for a center of the hole portion in the display plate portion which is magnetized on both sides in a case where the light shielding body is switched to the light shielding state. Therefore, the reliability of display can be improved, and the operability can be improved.

A display device according to the present invention is a light stippling display device that performs light stippling. In the device, a plurality of hole portions are formed on a display plate portion including a magnetized sheet which is magnetized on both sides, and the hole portion is opened and closed by a light shielding body made of a magnetic ball. Thereby, the position of the light shielding body is switched between a light transmitting state and a light shielding state. The light shielding body has directivity for a center of the hole portion in the display plate portion which is magnetized on both sides in a case where the light shielding body is switched to the light shielding state. Therefore, the reliability of display can be improved, and the operability can be improved.

Reconfigurable non-reciprocal integrated-optics-based devices are disclosed. The non-reciprocal devices include: a phase-sensitive device, such as a microring waveguide; a magneto-optic layer; and an electromagnet. These elements are operatively coupled such that a magnetic field generated by current flow through the electromagnet gives rise to a non-reciprocal phase shift in the phase-sensitive device. The non-reciprocal phase shift leads to a difference in the way that a light signal travels in the forward and backward directions through one or more bus waveguides that are operatively coupled with the phase-sensitive element. The non-reciprocity is reversible by reversing the direction of drive current flow in the electromagnet, which enables the inter-port connectivity of the ports of these bus waveguides to be reconfigured based on the direction of the drive current flow. Examples of reconfigurable isolator and circulator embodiments are described.

An optical logic device includes a distributed feedback laser configured to generate a first signal corresponding to distributed feedback laser output signal, the first signal being at a first wavelength. The device further includes a bandpass filter having a center frequency corresponding to the first wavelength. Additionally, the device can include an optical circulator having a first port coupled to a logic device input signal, a second port coupled to the first signal, and a third port coupled to the bandpass filter, wherein when the logic device input signal has a power above a predetermined threshold and there is a wavelength difference between the first wavelength and an input wavelength of the logic device input signal, a suppression of the first signal occurs.

An optical logic device includes a distributed feedback laser configured to generate a first signal corresponding to distributed feedback laser output signal, the first signal being at a first wavelength. The device further includes a bandpass filter having a center frequency corresponding to the first wavelength. Additionally, the device can include an optical circulator having a first port coupled to a logic device input signal, a second port coupled to the first signal, and a third port coupled to the bandpass filter, wherein when the logic device input signal has a power above a predetermined threshold and there is a wavelength difference between the first wavelength and an input wavelength of the logic device input signal, a suppression of the first signal occurs.

A method, apparatus and system for minimally intrusive fiber identification includes imparting a time-varying modulation onto an optical signal propagating in an optical fiber and subsequently detecting the presence of the time-varying modulation in the optical signal transmitting through the fiber to identify the fiber. In a specific embodiment of the invention, a time-varying curvature is imposed on the fiber to be identified and the presence of the resultant time variation in the transmitted power of a propagating optical signal is subsequently detected for identification of the manipulated fiber.

A method, apparatus and system for minimally intrusive fiber identification includes imparting a time-varying modulation onto an optical signal propagating in an optical fiber and subsequently detecting the presence of the time-varying modulation in the optical signal transmitting through the fiber to identify the fiber. In a specific embodiment of the invention, a time-varying curvature is imposed on the fiber to be identified and the presence of the resultant time variation in the transmitted power of a propagating optical signal is subsequently detected for identification of the manipulated fiber.

A two-dimensional photonic crystal formed of a square lattice of dielectric rods immersed in air, in which are inserted, in a controlled manner, defects that originate three waveguides and one resonant cavity. The cavity is formed of a ferrite cylinder with magneto-optical properties, and by two dielectric cylinders located near to the ferrite cylinder. It has the function of transmitting electromagnetic signals in a desired direction (clockwise or counterclockwise), defined by the sign of an external DC magnetic field H.sub.0.