Fiber optic amplification includes a photonic crystal fiber coupled to a pump laser through a first coupler. The pump laser emits a first electromagnetic radiation wave into the photonic crystal fiber at a first oscillation frequency and a second electromagnetic radiation wave into the photonic crystal fiber at a second oscillation frequency equaling the first oscillation frequency. The first and second electromagnetic radiation waves interact to generate a signal comprising an electromagnetic radiation wave at a third oscillation frequency and an idler comprising a fourth electromagnetic radiation wave at a fourth oscillation frequency to be generated and amplified through parametric amplification. Parametric amplification is achieved by four wave mixing. The photonic crystal fiber emits a parametric output signal based on the four wave mixing. A nonlinear crystal frequency doubles the parametric output signal through second-harmonic generation.

An optical amplifier of the present disclosure includes a Raman amplification unit and a parametric amplification unit that is configured of a second-order nonlinear element including a PPLN waveguide. In the optical amplifier, second harmonic lights are generated from a fundamental wave light having a wavelength that is slightly detuned to a shorter wavelength side with respect to a phase matching wavelength of the second-order nonlinear element, and is utilized as excitation light for the parametric amplification unit. By utilizing the excitation light based on the fundamental wave light of the wavelength detuned from the phase matching wavelength, a phase matching curve can be obtained in a wide band in a difference frequency generation (DFG) process of the second-order nonlinear element. The reduction in conversion efficiency of the wavelength near the excitation light in the parametric amplification unit is compensated by the Raman amplification unit.

Optimally detuned parametric amplification amplifies a signal in a resonator that is driven off-resonance, with respect to a signal mode, using a far-detuned pump. This pump establishes a parametric drive strength, and is “far-detuned” in that its detuning from the signal mode is greater than the drive strength. The amplitude and frequency of the pump are chosen so that the eigenfrequency of the resulting Bogoliobov mode matches a photonic loss rate of the Bogoliobov mode. In this case, a signal coupled into the Bogoliobov mode will be amplified with a gain that is broader and flatter than that achieved with conventional parametric amplification, and is not limited by a gain-bandwidth product. Optimally detuned parametric amplification may be used for degenerate or non-degenerate parametric amplification, and may be used to amplify microwaves, light, electronic signals, acoustic waves, or any other type of signal that can be amplified using conventional parametric amplification.

Embodiments of an optical signal copier and an optical parametric amplifier are disclosed herein, which are applied to the communications field. In the embodiments, the optical signal copier is included in the optical parametric amplifier, which generates an invalid signal in a process of transmitting signal light and pump light. The optical signal copier may separate the signal light from the invalid signal and then transmit the signal light to a signal processing module. In this way, the signal processing module may directly process the signal light that does not include the invalid signal, the invalid signal does not occupy transmission bandwidth of the optical parametric amplifier, and the effective transmission bandwidth of the optical parametric amplifier is relatively large.

An apparatus and a corresponding method for generating at least one random number are disclosed. The apparatus includes an optical parametric oscillator being pumped by a pump signal with a predetermined pump power and a predetermined pump frequency. The optical parametric oscillator is configured to operate in a period multiplication state for providing an oscillator output signal of alternating light pulses, the oscillator output signal having a period that is N-times the period of the pump signal, where N is an integer and N>I. The apparatus also includes a comparing unit being configured to compare the output signal with a reference signal, wherein the reference signal has a frequency that is 1/N of the predetermined pump frequency, and an evaluation unit being configured to generate the at least one random number based on the comparison of the output signal with the reference signal.

An optical waveguide structure comprising a nonlinear optical waveguide, a central region, a first side region, and a second side region. The central region is located within the nonlinear optical waveguide, wherein the central region comprises a nonlinear optical material. The first side region is on a first side of the central region and the second side region is on a second side of the central region. The nonlinear optical material comprising the central region has a first nonlinear coefficient that is larger than a second nonlinear coefficient of a second material comprising the first side region and the second side region.

In one aspect, a device is disclosed that includes one or more input ports structured to receive a pumping light at a pumping wavelength and a signal light at a signal wavelength, and one or more output ports structured to output light including an amplified signal light at the signal wavelength and a second harmonic idler light. The device includes a nonlinear optical material to mix the pumping light and the signal light and to cause nonlinear conversion of the pumping light into the amplified signal light and generate an idler light at an idler wavelength. The nonlinear optical material is further structured to convert the idler light into the second harmonic idler light which eliminates the idler light at the one or more output ports and prevents back-conversion of the amplified signal light and idler light to the pumping wavelength.

A nonlinear fiber interferometer is disclosed suitable for fiber sensor and other applications. A first nonlinear fiber section amplifies probe and conjugate sidebands of a pump through four-wave mixing. A second section introduces a phase shift to be measured, for example from a sensor. A third nonlinear fiber section amplifies with phase-sensitive gain to increase signal-to-noise ratio. Based on phase-sensitive output power of probe and/or conjugate components, the phase shift can be measured. Superior performance can be obtained by balancing gain between the (first and third) nonlinear sections. Non-fiber, for example photonic integrated circuit, embodiments are disclosed. Differential sensing, alternative detection schemes, sensing applications, associated methods, and other variations are disclosed.

In one aspect, a device is disclosed that includes one or more input ports structured to receive a pumping light at a pumping wavelength and a signal light at a signal wavelength, and one or more output ports structured to output light including an amplified signal light at the signal wavelength and a second harmonic idler light. The device includes a nonlinear optical material to mix the pumping light and the signal light and to cause nonlinear conversion of the pumping light into the amplified signal light and generate an idler light at an idler wavelength. The nonlinear optical material is further structured to convert the idler light into the second harmonic idler light which eliminates the idler light at the one or more output ports and prevents back-conversion of the amplified signal light and idler light to the pumping wavelength.

A system for generating a coherent laser light includes a light source configured to pump a first color laser light and a device configured to generate a coherent second color light and a coherent third color light. The device includes a waveguide configured to couple to the light source and a microring resonator coupled to the light source via the waveguide. The microring resonator is configured to generate a coherent second color light and a coherent third color light. The generation of the coherent second color light and the coherent third color light is based on hybrid-mode optical parametric oscillation.