A device for interferometric distance measurement includes a multiple wavelength light source, which supplies a light beam having at least three different wavelengths and is configured as a fiber laser, which includes at least three different Bragg gratings, whose grating constants are matched to the wavelengths generated. In addition, an interferometer unit is provided, which splits up the light beam into a measuring light beam and a reference light beam. The measuring light beam propagates in a measuring arm, in the direction of a measuring reflector, and there, it is reflected back; the reference light beam propagates in a reference arm, in the direction of a stationary reference reflector, and there, it is reflected back. The measuring and reference light beams reflected back by the measuring and reference reflectors are superimposed in an interfering manner to form an interference light beam. The interference light beam is split up via a detection unit such that, in each instance, a plurality of phase-shifted, partial interference signals result per wavelength. With the aid of a signal processing unit, an absolute position information item regarding the measuring reflector is determined from the partial interference signals of different wavelengths.

An optical amplifier is provided in which radiation levels experienced by an optical fiber are minimized. A sealed enclosure houses an optical fiber. An input optical signal enters on end of the fiber and an amplified output optical signal exits the other end of the optical fiber. Small particles embedded with a gas fill the interior of the enclosure. An optical pump supplies an amplification laser beam coupled to one of the ends of the optical fiber. Due to energy supplied by the amplification laser beam, the input optical signal is amplified upon exiting the optical fiber. At least a portion of the gas embedded in the small particles is released inside the enclosure when the small particles are subjected to heat to provide a gaseous interior in the enclosure that minimizes radiation levels experienced by the optical fiber due to external radiation.

Disclosed is a laser oscillation device. The laser oscillation device comprises: a first substrate; a second substrate which is provided above the first substrate and forms a wedge cell between the second substrate and the first substrate; a liquid crystal layer, formed by a liquid crystal having the same pitch, which is injected into the wedge cell; and a temperature controller system which is connected to both sides of the wedge cell and controls the temperatures of both sides of the wedge cell to be different from each other.

An example device in accordance with an aspect of the present disclosure includes a ring waveguide and bus waveguide. The ring waveguide has a first coupled portion associated with a first modal index, and the bus waveguide includes a second coupled portion associated with a second modal index. The second coupled portion is evanescently coupleable to the first coupled portion. A laser outcoupling and associated lasing output of the device is variable based on varying a difference between the first modal index and the second modal index to vary coupling between the first coupled portion and the second coupled portion, without varying modal indices of non-coupled portions of the ring waveguide and bus waveguide.

An optical amplifier is provided in which radiation levels experienced by an optical fiber are minimized. A sealed enclosure houses an optical fiber. An input optical signal enters on end of the fiber and an amplified output optical signal exits the other end of the optical fiber. Small particles embedded with a gas fill the interior of the enclosure. An optical pump supplies an amplification laser beam coupled to one of the ends of the optical fiber. Due to energy supplied by the amplification laser beam, the input optical signal is amplified upon exiting the optical fiber. At least a portion of the gas embedded in the small particles is released inside the enclosure when the small particles are subjected to heat to provide a gaseous interior in the enclosure that minimizes radiation levels experienced by the optical fiber due to external radiation.

Direct diode-pumped Ti:sapphire laser amplifiers use fiber-coupled laser diodes as pump beam sources. The pump beam may be polarized or non-polarized. Light at wavelengths below 527 nm may be used in cryogenic configurations. Multiple diode outputs may be polarization or spectrally combined.

An optical gain fiber for use in high power (e.g., greater than 500 W pump power) is proposed that is configured to exhibit a minimum bend radius such that the bend loss for the propagating LP.sub.01 mode is greater than about 0.03 dB/m. It has been discovered that this bend radius criteria, which is less stringent, than that typically suggested in the art (e.g., bend loss less than about 0.03 dB/m), meets the modal stability requirements at high power operation, since the increase in operating temperature of the fiber laser or amplifier has been found to somewhat relax the bend radius requirement (which was heretofore only measured at room temperature, not operating temperature). Modal stability is defined in terms of a reduced presence of unwanted higher-order modes (such as the LP.sub.11 mode) in the amplified output signal.

Ring resonators and methods of making and using the same are disclosed. In certain embodiments, a ring resonator may include a waveguide comprising a pump bus and a signal bus disposed adjacent a ring guide, the pump bus and signal bus configured to couple electromagnetic signals to and from ring guide, wherein at least a portion of the waveguide comprises erbium-doped silica and a cladding material disposed adjacent the waveguide, wherein the cladding material exhibits an index of refraction that is lower than an index of refraction of the waveguide.

A device and method for tuning a ring resonator using self-heating stabilization is provided. A light source is controlled to produce an optical signal, input to an optical ring resonator, at a power where self-heating shifts a resonance wavelength of the optical ring resonator by at least 10 picometers, the self-heating comprising absorption in the optical ring resonator of optical power from a received optical signal. Prior to using the optical ring resonator at least one of modulate and filter the optical signal at the optical ring resonator, a heater of the optical ring resonator is controlled to an operating temperature at which the resonance wavelength of the optical ring resonator is greater than a respective wavelength of the optical signal.

Improved Raman Fiber Laser (RFL) generators may include a mid-infrared fiber, e.g., a fiber comprising a tellurite glass, a chalcogenide glass, a fluoride glass, or similar material. A phase-shifted fiber Bragg grating may be inscribed in the fiber. A pump laser generator may be coupled with the fiber in order to supply a pump laser to the fiber. When stimulated by the pump laser, the RFL generator may emit an output laser having a mid-infrared wavelength. A tuner may be used to tune the output laser.