Abstract:
The present invention provides a method and apparatus for filtering an optical signal. The method includes receiving at least one input optical signal, forming first and second optical signals using the at least one input optical signal, and modifying at least one portion of the first optical signal using a plurality of non-waveguiding electro-optic phase adjusters. The method also includes forming an output optical signal by combining the first optical signal, including the at least one modified portion of the first optical signal, with the second optical signal.
Abstract:
In one embodiment, an optical modulator has a Mach-Zehnder interferometer (MZI) and an optical resonator coupled, via a tunable optical coupler, to one of the MZI internal arms. The optical resonator induces in the MZI frequency-dependent optical losses characterized by a comb of spectral resonances. The coupling strength between the optical resonator and the MZI set by the optical coupler controls the magnitude of the loss due to the resonances, while one or more optical phase shifter located in the optical resonator controls the spectral position of the resonances. Either the optical coupler or the optical phase shifter, or both, can be tuned to adjust the modulator's radio-frequency response curve.
Abstract:
Provided is an ultra-short pulse light source having an optical pulse generator 111 for emitting short pulse light, an optical amplifier 112 for amplifying the short pulse light output from the optical pulse generator 111 and an optical compressor 120 for compressing the short pulse light. The optical compressor 120 has multi-step configuration of steps polarization beam splitters 1211,2, optical fibers 1221,2, 1231,2 for compressing the incident pulse light, polarization rotating element 1241,2, for rotating the polarization direction of the incident light by 90 degrees to return the light to the optical fibers 1231,2, polarization maintaining optical fibers 1251,2 provided to the output side of the polarization beam splitters 1211,2, and a polarization maintaining optical fiber 1251 at the front step is connected to a polarization maintaining optical fiber 1252 at the rear step.
Abstract:
A simple and low-cost apparatus amplifies short optical pulses (e.g., in the femtosecond domain) to high pulse energies using energy stored in an enhancement cavity. The enhancement cavity is first filled with pump light from a pump laser; and a signal laser then directs a signal pulse into the cavity, where the signal pulse and pump laser both pass through a non-linear medium for parametric amplification of the signal pulse, wherein energy from the aggregated pump light is transferred to the signal pulse, which then exits the enhancement cavity.
Abstract:
A variable optical attenuator comprising a separation/combination birefringent element, fixed polarization rotation means, a convex lens, variable polarization rotation means, and a mirror which are arranged in that order. The fixed polarization rotation means has a compensation film Faraday element placed in a cylindrical permanent magnet, and the variable polarization rotation means has a base film Faraday element that is placed outside the cylindrical permanent magnet, and an electromagnet applying a variable magnetic field thereto. Thereby, both the Faraday elements are magnetized in directions different from each other.
Abstract:
A second harmonic laser beam is generated by passing a fundamental frequency laser beam through a single second harmonic generator (SHG) crystal more than two and preferably four times, to increase the amount of power converted from the fundamental beam into the second harmonic beam and to increase the overall efficiency of the conversion.
Abstract:
An all-optical logic gates comprises a nonlinear element such as an optical resonator configured to receive optical input signals, at least one of which is amplitude-modulated to include data. The nonlinear element is configured in relation to the carrier frequency of the optical input signals to perform a logic operation based on the resonant frequency of the nonlinear element in relation to the carrier frequency. Based on the optical input signals, the nonlinear element generates an optical output signal having a binary logic level. A combining medium can be used to combine the optical input signals for discrimination by the nonlinear element to generate the optical output signal. Various embodiments include all-optical AND, NOT, NAND, NOR, OR, XOR, and XNOR gates and memory latch.
Abstract:
A reciprocating optical modulator includes a continuous light path fulfilling an amplification function, an optical modulation part formed on the light path, a first optical band-pass filter and a second optical band-pass filter formed to nip the optical modulation part therebetween and a device to introduce exciting light for exciting the light path. The optical modulation part, first and second optical band-pass filters and device are disposed on the light path as formed in a single optical crystal or in a multiplicity of optical crystals. The first optical band-pass filter admits incident light and reflects light having the incident light modulated. The second optical bandpass filter reflects the incident light and emits the light having the incident light modulated. The modulator can also include a third optical band-pass filter disposed between the optical modulation part and the second optical band-pass filter for removing the incident light.
Abstract:
An optical isolator for transmitting light in a first direction along an optical pathway and blocking light in a second direction along an optical pathway. The optical isolator includes an input polarizer having a pass axis at a first angle, an output polarizer having a pass axis at a second angle, a Faraday rotator material between the polarizers having a Verdet constant and an axis of maximum length therethrough, generation means for generating a magnetic field around and inside the rotator material, and at least one reflector configured to define an optical length through the rotator material which is longer than the axis therethrough. The optical pathway length through the rotator material, the magnetic field strength, and the Verdet constant are selected so as to rotate light through the Faraday rotator material from the first angle to the second angle.
Abstract:
A phasor can be employed within the resonator of an optical parametric oscillator (OPO) to adjust the absolute and relative phase of OPO beams. An embodiment of the invention comprises an OPO having at least one phasor for receiving and adjusting the phase of one or more beams resonating within the optical cavity which forms part of the OPO. Smooth alteration of the phases of the OPO beams using the at least one phasor facilitates continuous tuning of the wavelength of at least one of the beams. In another embodiment, the at least one phasor may be a translatable wedge or have adjustable refractive index to alter the phases of the OPO beams. In an additional embodiment, each at least one phasor may be comprised of more than one material, held fixedly together.