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

Various example embodiments relate to active optical fibers and devices comprising active optical fibers. A section of an active optical fiber may comprise an active core doped with at least one rare-earth element. The active core may have a first refractive index and be configured to support a single mode operation of an optical signal. The section of the active optical fiber may further comprise at least one cladding layer having a second refractive index. The second refractive index may be less than the first refractive index. Birefringence of the active core may be less than 10.sup.-5. Fiber lasers and power amplifiers comprising the section of the active optical fiber are also disclosed.

Technologies pertaining to accounting for pulse history effects are described herein. In connection with accounting for pulse history effects, an amount of time between a first current pulse and a second current pulse that are to be transmitted to a pulsed laser is determined. Based upon such an amount of time, a determination is made as to whether a porch pulse is to be prepended to the second current pulse. When the porch pulse is to be prepended to the second current pulse, an amplitude and duration of the porch pulse are computed based upon the amount of time. The porch pulse is transmitted to the pulsed laser immediately followed by the second current pulse, wherein the porch pulse pre-charges the pulsed laser for emitting a pulse of light based upon the second current pulse.

Technologies pertaining to accounting for pulse history effects are described herein. In connection with accounting for pulse history effects, an amount of time between a first current pulse and a second current pulse that are to be transmitted to a pulsed laser is determined. Based upon such an amount of time, a determination is made as to whether a porch pulse is to be prepended to the second current pulse. When the porch pulse is to be prepended to the second current pulse, an amplitude and duration of the porch pulse are computed based upon the amount of time. The porch pulse is transmitted to the pulsed laser immediately followed by the second current pulse, wherein the porch pulse pre-charges the pulsed laser for emitting a pulse of light based upon the second current pulse.

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 laser module produces pulsed laser energy in a wavelength range of 495-580 nm based on duration, peak power, and interval parameter information. An envelope timer controls the total duration of all micropulses based on the duration and interval parameters via a pulse-width modulated (PWM) output to a micropulse timer, which in turn outputs a PWM micropulse signal. A light emitting diode driver outputs a laser current through a diode based on the micropulse signal and a dimming signal to produce the pulsed laser energy. The integrator compares a signal corresponding to a detected power level of the laser energy to a signal corresponding to the peak power parameter and outputs the dimming signal. The resulting micropulse durations are in the range of 50 to 300 microseconds for periods of about 2 milliseconds, with a duty cycle ranging from 5 to 15%. The overall pulse parameters are duration from 10 microseconds to 1.5 seconds, with periods of any value. The pulsed laser energy is delivered by ophthalmologic laser treatment devices to an eye of a patient.

A pulsed fiber generator is configured with a unidirectional ring waveguide configured to emit a train of pulses. The ring waveguide includes multiple fiber amplifiers, chirping fiber components coupled to respective outputs of first and second fiber amplifiers, and multiple spectral filters coupled to respective outputs of the chirping components. The filters have respective spectral band passes centered around different central wavelengths so as to provide leakage of light along the ring cavity in response to nonlinear processes induced in the ring cavity. The pulse generator operates at a preliminary stage during which it is configured to develop a pitch to a signal, and at a steady stage during which it is configured to output a train of pulses through an output coupler at most once per a single round trip of the signal.

A pulsed fiber generator is configured with a unidirectional ring waveguide configured to emit a train of pulses. The ring waveguide includes multiple fiber amplifiers, chirping fiber components coupled to respective outputs of first and second fiber amplifiers, and multiple spectral filters coupled to respective outputs of the chirping components. The filters have respective spectral band passes centered around different central wavelengths so as to provide leakage of light along the ring cavity in response to nonlinear processes induced in the ring cavity. The pulse generator operates at a preliminary stage during which it is configured to develop a pitch to a signal, and at a steady stage during which it is configured to output a train of pulses through an output coupler at most once per a single round trip of the signal.

A laser system comprising an RE:XAB gain medium within a resonator cavity. X is selected from Ca, Lu, Yb, Nd, Sm, Eu, Gd, Ga, Tb, Dy, Ho, Er, and RE is selected from Lu, Y, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Pr, Tm, Cr, Ho. The system further comprises a pumping source having optical output directed towards the gain medium. A laser controller operates the pumping source. The system further comprises a heat spreader, the heat spreader in thermal communication with the gain medium through a surface wherein the pump source has optical output incident.

A method and system for amplifying optical signals includes generating idler signals for input signals using an optical pump at a first non-linear element (NLE). An intermediate stage including a Raman amplifier performs pump amplification using the output from the first NLE along a single optical path. Optical power monitoring of the input signals may be used for power equalization. The intermediate stage may include a wavelength selective switch for a certain degree of phase modulation. The phase-sensitive amplified signal is generated at a second NLE using the optical pump. Optical power monitoring of the input signals may be used for power equalization and other control functions to achieve low-noise operation.