Phase-sensitive Fiber Optical Parametric Amplifier Research Articles

Enhanced analog-optical link performance with noiseless phase-sensitive fiber optical parametric amplifiers.

In this paper, we investigate the enhancement of analog optical link performance with noiseless phase-sensitive fiber optical parametric amplifiers. The influence of different noise sources in the link impacts the quality of analog optical signals, especially with low optical signal power, which has not been investigated before. Theoretically, the increase in signal-to-noise ratio and spurious-free dynamic range can be up to ∼6 dB and ∼4 dB, respectively, if the noise figure of optical pre-amplifier drops 3 dB when the received optical power is less than -65 dBm. In addition, experiments based on a 1.3 dB-noise-figure phase-sensitive fiber optical parametric amplifier and conventional optical pre-amplifiers are implemented, and the measured results agree with the theoretical expectations. This illustrates that noiseless phase-sensitive optical amplification may pave the way to long-haul distribution of analog optical signals and find applications in microwave-photonic systems.

Investigation of Four-Wave-Mixing Crosstalk in Phase-Sensitive Fiber Optical Parametric Amplifier

Four-wave-mixing (FWM) crosstalk in frequency nondegenerate phase-sensitive fiber optical parametric amplifiers (FOPAs) applied for wavelength-division-multiplexed (WDM) signals is investigated experimentally and theoretically. We analyze significant FWM interactions that can generate crosstalk components in the signal band. Approximate expressions are developed for the FWM crosstalk to conveniently estimate how it scales with the system parameters. The analytical results agree well with the experimental results and simulations. The results show that the FWM crosstalk grows dramatically with the increase of the system parameters, including input signal power per channel, signal gain, the length of nonlinear fiber, and signal channel number. We also compare the FWM crosstalk in the phase-sensitive FOPA and the phase-insensitive FOPA experimentally and explain the difference of their crosstalk behaviors through theoretical analysis and simulations. The results show that, due to the presence of idlers at the input, the phase-sensitive FOPA produces higher crosstalk than the phase-insensitive FOPA even when they have equivalent signal gains. It indicates that the crosstalk in the phase-sensitive FOPA is more detrimental so that careful design of the amplifier to suppress the impact of the FWM crosstalk is necessary. The analytical solutions obtained in this paper are useful in the design of PS-FOPAs for amplifying WDM signals.

Phase-sensitive fiber-based parametric all-optical switch.

We experimentally demonstrate, for the first time, an all-optical switch in a phase-sensitive fiber optic parametric amplifier operated in saturation. We study the effect of phase variation of the signal and idler waves on the pump power depletion. By changing the phase of a 0.9 mW signal/idler pair wave by π/2 rad, a pump power extinction ratio of 30.4 dB is achieved. Static and dynamic characterizations are also performed and time domain results presented.

Investigation on gain characteristics in non-degenerate cascaded phase sensitive parametric amplifiers

We theoretically and experimentally show the impact of the ratio between the signal and idler generated from the PIA part on the gain characteristics in the continuous wave (CW) pump non-degenerate cascaded phase-sensitive fiber optical parametric amplifier (PS-FOPA). The results show that the length of highly nonlinear fiber (HNLF) used for generating the idler can cause the variation of power ratio between the idler and signal, which significantly affects the gain characteristics of the PS-FOPA under the small signal gain condition. To obtain high gain, it is better to choose long HNLF to generate idler. In our experiment, 5.5 dB gain and 18 nm bandwidth (on/off gain>10 dBm) in PS-FOPA can be achieved when 300 m-long HNLF instead of 200 m-long HNLF is used in PIA.

Phase-to-phase and phase-to-amplitude transfer characteristics of a nondegenerate-idler phase-sensitive amplifier

For the first time to our knowledge, the phase-to-phase and phase-to-amplitude transfer functions of a nondegenerate-idler phase-sensitive fiber optic parametric amplifier are experimentally measured. Additionally, analytically and numerically obtained transfer curves show excellent agreement with the experimental curves. The experimental results were obtained by imposing a linear phase modulation onto the signal and idler wave simultaneously, and detecting the input and output signal using a self-homodyne coherent receiver.

In-line frequency-nondegenerate phase-sensitive fiber-optical parametric amplifier

We demonstrate a phase-sensitive fiber-optical parametric amplifier based on frequency-nondegenerate four-wave mixing in the telecom band. An input signal is phase-sensitively amplified and the measured gain response complies well with the theory. Efficient phase-sensitive amplification can be achieved even after transmitting an optical double-sideband signal over 25 km of single-mode fiber.

Gain characteristics of a frequency nondegenerate phase-sensitive fiber-optic parametric amplifier with phase self-stabilized input

We experimentally demonstrate, for the first time to our knowledge, a phase-sensitive amplifier based on frequency nondegenerate parametric amplification in optical fiber, where the input signal-idler pair is prepared all-optically. Using two fiber-optic parametric amplifier sections separated by a fiber-based wavelength-dependent phase shifter, we observe and investigate phase-sensitive gain profile in the 1550 nm region both experimentally and theoretically. The realized scheme automatically generates gain-defining phase that is environmentally stable, making it advantageous for building phase-sensitive transmission links.