Optical pulse shaping using optical coherent transients

Abstract

Using multiple temporally-overlapped, frequency offset and phase-tuned, linear frequency chirps, a new method of multi-GHz optical coherent transient optical pulse shaping and processing in inhomogeneously broadened rare-earth doped crystals is proposed. Using this technique with properly chirped laser sources, multi-GHz processing can be controlled with conventional low-bandwidth electronics and optical modulators. Specifically, this technique enables pulse shaping in the MHz to THz frequency regime with time-bandwidth-products exceeding 100,000, filling the gap between the operating regimes of femtosecond pulse shaping and analog electronics. The low bandwidth (~20 MHz) proof-of-concept demonstrations presented in this paper include pulse train creation, selfconvolution, auto-correlation, and chirped pulse compression.

Broadband demonstrations of true-time delay using linear sideband chirped programming and optical coherent transients

“…Due to these advantages, the LSC programming method could be utilized for several applications and is a particularly attractive approach to OCT steering of conventional phased array radar systems. LSC programming can be extended to the creation of arbitrary analog optical waveforms, by introducing LSCs with multiple frequency offsets [7]. The technique also has several practical advantages as it utilizes commercially available telecommunications equipment such as integrated optics phase modulators and pulse pattern generators and cost effective stabilized ECDLs.…”

“…Some of the more recent proposals include systems for true-time delay (TTD) beam steering of phased array radars [2], range-doppler correlators [3], high bandwidth RF spectrometers [4], continuous optical correlators [5], and pulse compression and arbitrary waveform generation [6,7]. Spatial-spectral holography (SSH) utilizing rare-earth ion-doped crystals (such as Tm 3þ : YAG) has the potential to reach bandwidths of > 10 GHz with time-bandwidth products exceeding 10 5 : However, the practicality of SSH has been questioned, as previous demonstrations have either been low bandwidth [2] or have used expensive picosecond lasers to create gratings [8].…”

Numerical modeling of optical coherent transient processes with complex configurations—III: Noisy laser source

“…Optical coherent transients (OCT) in an inhomogeneously broadened medium, such as rare earth ion-doped crystals, are the basis of various applications including RF spectral analysis [1][2][3][4], pulse shaping [5], true-time delay [6], radar signal processing [7,8], quantum memory [9], and quantum computing [10]. In these applications, the stochastic processes caused by noises in the excitation laser field disturb the coherent interaction between the laser field and the medium, which usually degrades the system performance, such as signal-to-noise ratio, dynamic range, and quantum operation fidelity.…”

Demonstration of a spatial–spectral holographic LIDAR range-Doppler processor

“…In 0.5%-doped Tm 3þ : YAG cooled to 4.8 K (the material used in this work), the inhomogeneously broadened linewidth spans G I ¼ 25 GHz, while the homogeneous absorption width is G H ¼ 10-100 kHz ¼ 1=T 2 (where T 2 is the coherence time), and the lifetime is T 1 ¼ 10 ms [2]. SSH techniques have been used in a wide range of one-dimensional photonic signal processing applications, including highbandwidth signal correlation [3], arbitrary waveform generation [4], multi-GHz RF spectrum analysis [5,6] and radar ranging [7], to name but a few. In addition, further architectures that harness the spatial as well as spectral parallelism are emerging, including a high-bandwidth RF imager [1], time-integrating correlator [8], range-Doppler radar [7] and range-Doppler laser interferometric Doppler and ranging (LIDAR) [9,10].…”