Compact photonic delay line constructed by holographic optical elements

To fully support phased-array antenna and other applications, a 3-range (long time, moderate time, and short time) delay line structures with holographic optical elements is proposed. Flexibility, light-weight, on-axis coupling, easy alignment, easy fabrication, and compactness are their advantages. When use holographic optical elements to build the photonic delay line system, all of the delay and non-delay paths in these three photonic delay lines are setting in a compact structure. They do not need any extra components, such as mirrors and optical paths in free space, and can bear stronger vibration. Therefore, the holographic optical elements are more suitable to design the photonic delay lines. In these three structures, their losses and crosstalk s are balanced. All of delay and non-delay cases in these three delay line structures, their crosstalk, signal-to-noise ratio, and loss are 1/81,000, 59.1 dB, and 3.2 dB, respectively. Finally, to support complete applications, a polarization independent photonic delay line system with holographic optical elements is proposed, too.