Oo Kaw Lim

Ultra-Low-Noise Inline Fiber-Optic Phase-Sensitive Amplifier for Analog Optical Signals

We demonstrate a near-noiseless amplification scheme for analog optical signals. The noise figure of a frequency-non-degenerate phase-sensitive fiber parametric amplifier is measured to be close to the Raman limit (~≃ 0.5 dB) in the fiber.

Quantum enhancement of a coherent ladar receiver using phase-sensitive amplification

We demonstrate a balanced-homodyne LADAR receiver employing a phase-sensitive amplifier (PSA) to raise the effective photon detection efficiency (PDE) to nearly 100%. Since typical LADAR receivers suffer from losses in the receive optical train that routinely limit overall PDE to less than 50% thus degrading SNR, PSA can provide significant improvement through amplification with noise figure near 0 dB. Receiver inefficiencies arise from sub-unity quantum efficiency, array fill factors, signal-local oscillator mixing efficiency (in coherent receivers), etc. The quantum-enhanced LADAR receiver described herein is employed in target discrimination scenarios as well as in imaging applications. We present results showing the improvement in detection performance achieved with a PSA, and discuss the performance advantage when compared to the use of a phase-insensitive amplifier, which cannot amplify noiselessly.

Fundamental eigenmode of traveling-wave phase-sensitive optical parametric amplifier: experimental generation and verification

We investigate experimentally the eigenmodes of a Gaussian-beam-pumped traveling-wave phase-sensitive optical parametric amplifier (PSA). By varying the waist of an input LG(00) signal mode, we show that PSA performance improves with increasing spatial overlap between the input and the theoretically predicted fundamental eigenmode. For optimum waist, we report amplification and deamplification markedly higher than those observed for the traditional case of signal waist=√2× (pump waist). Lastly, we demonstrate the generation and verification of the PSA fundamental eigenmode.

Enhanced optical resolution in target detection with phase-sensitive versus phase-insensitive pre-amplification

We investigate the performance of phase-sensitive versus phase-insensitive pre-amplification in optical resolution enhancement with a binary hypothesis test. Phase-sensitive pre-amplification is shown to outperform phaseinsensitive pre-amplification by more than 2 dB.

Enhanced Optical Resolution with Phase‐Sensitive Preamplification in Coherent Image Detection

We demonstrate enhanced optical resolution in target detection by means of phase‐sensitive preamplification. In a two‐versus‐one‐target hypothesis testing experiment, we show 3‐dB improvement in signal‐to‐noise ratio (SNR) for same error probability with 10‐dB phase‐sensitive gain in homodyne detection.

Amplification of a squeezed-quadrature using a cascaded traveling-wave phase-sensitive optical parametric amplifier

We demonstrate a two-stage system of cascaded traveling-wave phase-sensitive optical parametric amplifiers, achieving 3.6dB squeezed-quadrature amplification (0.9dB deamplification) on top of 1.3 dB squeezing provided by the first stage.

Near-noiseless amplification for analog optical signals

We demonstrate an ultra-low-noise fiber-optic phase-sensitive amplification scheme that is capable of providing more than 10 dB of gain on a 40 MHz analog signal.