Structures for response shaping in frequency and time domain, include an optical response shaper and/or a modulator device with multiple injection. The device comprises a resonator having an enclosed geometric structure, for example a ring or racetrack structure, at least two injecting optical waveguides approaching the resonator to define at least two coupling regions between the resonator and the injecting waveguides, and may define at least two Free Spectral Range states. One or both of the coupling regions has a coupling coefficient selected for a predetermined frequency or time response, and the coupling coefficient or other device parameters may be variable, in some case in real time to render the response programmably variable.

An optical module for preventing laser beam leakage and a control method thereof are disclosed. The optical module including a current control circuit, a first transistor, a laser, and a laser control unit. The laser control unit is configured to: if it is detected that an optical fiber is inserted in the optical fiber interface, perform control to turn on the laser, or if it is detected that no optical fiber is inserted in the optical fiber interface, control the laser to remain in an off state. A laser beam is effectively prevented from causing human bodily injury when an optical fiber is not inserted in an optical fiber interface.

A tunable laser includes a reflective silicon optical amplifier (RSOA) with a reflective end and an interface end and an array of narrow-band reflectors, which each have a different center wavelength. It also includes a silicon-photonic optical switch, having an input port and N output ports that are coupled to a different narrow-band reflector in the array of narrow-band reflectors. The tunable laser also includes an optical waveguide coupled between the interface end of the RSOA and the input of the silicon-photonic optical switch. The frequency of this tunable laser can be tuned in discrete increments by selectively coupling the input port of the silicon-photonic optical switch to one of the N output ports, thereby causing the RSOA to form a lasing cavity with a selected narrow-band reflector coupled to the selected output port. The tunable laser also includes a laser output optically coupled to the lasing cavity.

Resonant recharge for synchronous pulsed laser operation. At least one example embodiment is a method of activating a laser diode, the method including: creating an oscillating voltage at a node between an inductor and a first capacitor, the oscillating voltage having a positive half-cycle and a negative half-cycle; charging a firing capacitor during a positive half-cycle of the oscillating voltage, the charging from the node and through a diode; and driving, during a negative half-cycle of the oscillating voltage, a pulse of current from the firing capacitance through a laser diode.

A laser structure comprising a first photonic crystal surface emitting laser (PCSEL), a second PCSEL, and a coupling region that extends between the first PCSEL and the second PCSEL along a longitudinal axis and that is electrically controllable so as to be capable of coherently coupling the first PCSEL to the second PCSEL. Each PCSEL include an active layer, a photonic crystal, and a two-dimensional periodic array distributed in an array plane parallel to the longitudinal axis within the photonic crystal where the two-dimensional periodic array is formed of regions having a refractive index that is different to the surrounding photonic crystal.

The disclosed embodiments provide a tunable laser that includes a set of M reflective silicon optical amplifiers (RSOAs) and a set of N narrow-band reflectors. It also includes a silicon-photonic optical switch, having M amplifier ports, which are coupled through a set of M optical waveguides to the set of M RSOAs, and N reflector ports, which are coupled to the set of N narrow-band reflectors. The tunable laser also includes a switching mechanism that facilitates coupling at least one selected amplifier port from the M amplifier ports with a selected reflector port from the N reflector ports, thereby causing an RSOA coupled to the selected amplifier port to form a lasing cavity with a narrow-band reflector coupled to the selected reflector port. The tunable laser also includes a laser output, which is optically coupled to the lasing cavity.

Structures for response shaping in frequency and time domain, include an optical response shaper and/or a modulator device with multiple injection. The device comprises a resonator having an enclosed geometric structure, for example a ring or racetrack structure, at least two injecting optical waveguides approaching the resonator to define at least two coupling regions between the resonator and the injecting waveguides, and may define at least two Free Spectral Range states.

One or both of the coupling regions has a coupling coefficient selected for a predetermined frequency or time response, and the coupling coefficient or other device parameters may be variable, in some case in real time to render the response programmably variable.

A pixel structure for a vertical cavity surface emitting laser has an emission window. The pixel structure includes a plurality of sub-pixels in the emission window. Bright-area sub-pixels emit light and dark-area sub-pixels having no light emission. The bright-area sub-pixels and the dark-area sub-pixels are arranged in a pattern in the emission window. Various patterns are possible. Different structures for implementing the sub-pixels are described.

A light source device according to an embodiment is used with a light guide member and a wavelength converting member, and includes a light-emitting element, a light sensor, and a driving unit. The light-emitting element radiates a light beam to be incident on a first end of the light guide member by being supplied with a drive current. The light sensor detects signal light, which has been incident on a second end of the light guide member and transmitted to the first end. The driving unit supplies the drive current to the light-emitting element and controls the drive current based on a result of detection of the signal light.

This application describes a wavelength-tunable laser apparatus, which reduces complexity of wavelength tuning of a laser. The laser includes a reflective gain unit, an optical phase shifter, a coupler, and a passive filter unit array. Furthermore, an output port of the reflective gain unit is connected to an input port of the optical phase shifter, an output port of the optical phase shifter is connected to an input port of the coupler, a first output port of the coupler is connected to an input port of the passive filter unit array, and a second output port of the coupler is an output port of the laser. The passive filter unit array includes a plurality of passive filter units, where any two of the plurality of passive filter units have different wavelength tuning ranges, and each filter unit has a linearly tunable wavelength.