A photonic device is configured with a photonic integrated circuit (PIC), a plurality of fiber-based gain mediums in optical communication with the PIC, and at least one optical pump outputting pump light coupled into two or more gain mediums. At least one of the fiber-based gain media and the PIC form a hybrid resonant optical cavity there between operative to lase light into the PIC. The gain media further include one or more fiber amplifiers amplifying light signals coupled into and decoupled from the PIC. The photonic device is integrated with Si photonic passive and active photonic elements, while ail fiber links between the gain media and PIC are free from these elements.

A device and method are provided for more efficient thermal management of optoelectronic devices. A microfluidic distribution apparatus embedded with the optoelectronic device uses a working fluid in phase change to passively remove heat from an optoelectronic device. The working fluid undergoes phase change through various conversions between a liquid state and a two-phase liquid-vapor state to facilitate evaporation and condensation processes as the working fluid is distributed through micro-structures in the embedded microfluidic distribution apparatus. Passive two-phase cooling provides high thermal performance due to the use of the latent heat of a fluid in phase change, as well as the presence of favorable two-phase flow regimes at micro-scale dimensions.

An integrated optical linewidth reduction system based on optical feedback and a low-speed electronic control loop to control the optical feedback. Light is tapped and reflected back to the laser with an amplitude, phase or both amplitude and phase adjustment such that the linewidth of the laser is lower than the free-running laser linewidth. The amplitude of the feedback signal may be controlled using an optical attenuator. The phase of the feedback signal may be controlled using a phase shifter. The amplitude of the optical feedback may be monitored by means of a filter and a photodetector, or just a photodetector. The amplitude and/or phase of the optical feedback is monitored by means of a frequency/phase noise discriminator. The phase shifter can be an endless phase shifter

A method of generating an optical pulse train using spectral extension by optical phase modulation, spectral narrowing by optical phase demodulation, and narrow linewidth optical filtering is disclosed. It is also described that the wavelength selection of light using a chromatic dispersion element between the optical phase modulator can enrich the method. Systems include an in-line optical setup and a ring-type laser cavity for mode-locked laser outputs. The duration with which the electrical signals driving the modulators are opposed determines the line width of the optical pulses, and the opposite repetition of the electrical signals defines the rate of repetition of an optical pulse train generated. Four different arrangements of electrical signals in the time domain or phase domain make it possible to control the generation of optical pulses and the wavelength selection of the light. (i) A signal arrangement comprising sinusoidal electrical signals with a slight frequency difference. (ii) A signal arrangement comprising a phase-shift between electrical signals. (iii) A signal arrangement comprising a phase-shift between electrical signals depending on the amplitude of the bits. (iv) A signal arrangement comprising random electric waves that repeat themselves over a predefined period to allow the insertion of controllable time delays between each other.

An acousto-optic modulator (AOM) laser frequency shifter system includes a laser configured to generate an incident beam, a first optical splitter optically coupled to the laser and configured to split the incident beam into at least one portion of the incident beam, at least one phase-shift channel optically coupled to the first optical splitter and configured to generate at least one frequency-shifted beam with an acousto-optic modulator (AOM) from the at least one portion of the incident beam received from the first optical splitter, and a second optical splitter configured to receive the at least one frequency-shifted beam from the at least one phase-shift channel and configured to direct the at least one frequency-shifted beam to an interferometer configured to acquire an interferogram of a sample with the at least one frequency-shifted beam.

An apparatus and method for calculating the frequency of the light.

A laser adjustment method includes a first adjustment step and a second adjustment step. In the first adjustment step, using a light detector detecting a second harmonic light, optical intensity and wavelength of the second harmonic light is detected and a first temperature adjuster is adjusted to adjust temperatures of a Nd:YVO.sub.4 crystal and a KTP crystal such that the detected wavelength of the second harmonic light approaches a desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value. In the second adjustment step, after the first adjustment step, a temperature of an etalon is adjusted by a second temperature adjuster such that the detected wavelength of the second harmonic light approaches the desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value.

A short-pulse, narrowband, line-selectable and tunable solid-state laser is described. The device requires a pump source, an active solid-state laser medium, an enclosing cavity, mirrors to contain the light, a method of removing the pulse from the cavity, a wavelength selection system, and a laser linewidth narrowing system. One implementation of this is an Er:YAG laser, side pumped by semiconductor lasers in the erbium absorption band near 1475 nm, with an intracavity etalon and a switchable spectral filter. To remove the pulse from the cavity, cavity dumping issues, which assures constant pulse energy and pulse length over a range of repetition rates, in this case from 100 Hz to 20 kHz. Line selection is obtained by use of wavelength filters and fine tuning with an etalon, which also acts as the linewidth narrowing system.

A device may include a first photodetector to generate a first current based on an optical power of an optical beam. The device may include a beam splitter to split a portion of the optical beam into a first beam and a second beam. The device may include a wavelength filter to filter the first beam and the second beam. The wavelength filter may filter the second beam differently than the first beam based on a difference between an optical path length of the first beam and an optical path length of the second beam through the wavelength filter. The device may include second and third photodetectors to respectively receive, after the wavelength filter, the first beam and the second beam and to generate respective second currents.

Disclosed herein is a single pulse laser apparatus that includes: a resonator having a first mirror, a second mirror, a gain medium, an electro-optic modulator (EOM) configured to perform single pulse switching, and an acousto-optic modulator (AOM) configured to perform mode-locking; a photodiode configured to measure a laser beam oscillated in the resonator; a synchronizer configured to convert an electrical signal, which is generated by measuring the laser beam, into a transistor-transistor logic (TTL) signal; a delay unit configured to set a delay time for the TTL signal to synchronize the EOM and the AOM and output a trigger TTL signal according to the delay time; an AOM driver configured to input the trigger TTL signal to the AOM that performs mode-locking and drive the AOM; and an EOM driver configured to input the trigger TTL signal to the EOM that performs single pulse switching and drive the EOM.