A photonic frequency discriminator based on a two wavelength delayed self-heterodyne interferometer for low phase noise tunable micro/mm wave synthesis

N Kuse,M E Fermann

doi:10.1038/s41598-018-31712-y

Abstract

Low phase noise frequency synthesizers are of paramount interest in many areas of micro-mm wave technology, encompassing for example advanced wireless communication, radar, radio-astronomy, and precision instrumentation. Although this broad research field is not bereft of methods for the generation of either low phase noise micro- or mm waves, no universal system applicable to low phase noise generation for micro and mm waves has yet been demonstrated. Here we propose a new photonic frequency discriminator based on a two wavelength delayed self-heterodyne interferometer which is compatible with such an objective. The photonic frequency discriminator can be a reference both for micro and mm waves to lower their phase noise. As a proof-of-concept, we demonstrate a low phase noise tunable OEO (6–18 GHz) and locking of a heterodyne beat between two cw lasers (10–400 GHz) with low relative phase noise. The required components for the photonic frequency discriminator are off-the-shelf and can be readily assembled. We believe this new type of photonic frequency discriminator will enable a new generation of universal precision tunable sources for the X, K, V, W and mm-bands and beyond.

Highlights

Low phase noise micro – mm wave oscillators are indispensable for wireless communication[1,2], radar[3], radio-astronomy[4], and modern instrumentation
We compared the obtained phase noise of our precision tunable opto-electronic oscillators (OEOs) with other frequency tunable synthesizers, including other types of tunable OEOs19–21,23, systems based on optical frequency combs[7], and commercial frequency synthesizers based on RF technology (e.g. N5183B with low phase noise option from Keysight Technologies) (Table 1)
We propose and demonstrate a novel ultra-high sensitivity photonic frequency discriminator, which can serve as a universal tool for low phase noise micro and mm-THz wave synthesis

Summary

Introduction

Low phase noise micro – mm wave oscillators are indispensable for wireless communication[1,2], radar[3], radio-astronomy[4], and modern instrumentation. Low phase noise mm waves facilitate the use of complex modulation formats for mm wave communication systems, which have been suggested for overcoming the capacity bottleneck for future wireless ultra-high bandwidth data transfer. Another example is Doppler radar, in which sensitivity is strongly affected by phase noise. There are two alternative photonic methods, which can generate tunable carrier frequencies and have been used for real world application: opto-electronic oscillators (OEOs) (50 GHz)[14,15,16,17,18].

Methods

Findings

Discussion

Conclusion