Measuring sub-picosecond optical propagation delay changes on optical fibre using photonics and radio frequency components

2017 ◽  
Author(s):  
Roufurd P. M. Julie ◽  
Thomas Abbott
Keyword(s):  
Radio Frequency ◽  
Optical Fibre ◽  
Propagation Delay ◽  
Optical Propagation ◽  
Frequency Components

scholarly journals Multifrequency Radio Properties of the Crab Pulsar

1996 ◽  
Vol 160 ◽  
pp. 283-284
Author(s):  
David A. Moffett ◽  
Timothy H. Hankins
Keyword(s):  
Radio Frequency ◽  
Spectral Index ◽  
Noise Level ◽  
Phased Array ◽  
Crab Nebula ◽  
Phase Changes ◽  
Crab Pulsar ◽  
Spectral Indices ◽  
Frequency Components ◽  
Later Phase

During a single Arecibo observation in 1981 of the Crab pulsar, a profile at 4.7 GHz was recorded which appeared to contain additional components and an interpulse (IP) shifted to earlier phase. The experiment was continued at the VLA, taking advantage of its phased array mode to form a synthesized beam, which resolves out the bright Crab Nebula background. Observations were conducted between February 9 and May 27, 1994, at 0.33, 1.4, 4.9, and 8.4 GHz. Additional radio profiles presented here were recorded at Arecibo (0.43, 0.6, and 4.7GHz) and Effelsberg (2.7GHz) by Hankins & Fowler (unpublished).In Figure 1 we have plotted a summary of normalized profiles from several radio frequencies and infrared. The VLA profiles are time aligned, while the rest are aligned to the main pulse (MP). A new component (labeled LFC) appears 36° ahead of the MP between 0.6 and 4.9 GHz, not coincident with the position of the precursor, and with a spectral index similar to that of the MP. The MP disappears at 8.4 GHz, probably due to spectral effects. The IP appears to undergo a transition in phase and flux, disappearing at 2.7 GHz and reappearing 10° earlier at 4.7 GHz with a radically different spectral index. Two high radio frequency components (labeled HFC1 and HFC2) appear at 4.9 and 8.4 GHz, and possibly at the noise level at 1.4 GHz. They have flatter spectral indices than the MP and IP and their centroid phase changes with respect to the MP – moving to later phase with increasing frequency. The infrared profile exhibits a “bump”, or third component near the same phase as HFC1 and HFC2.

scholarly journals Evaluation of optical fibre sensors in the electrical domain

2020 ◽  
Vol 9 (2) ◽  
pp. 199-208
Author(s):  
Ulrich Nordmeyer ◽  
Niels Neumann ◽  
Xiaozhou Wang ◽  
Dirk Plettemeier ◽  
Torsten Thiel ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Optical Fibre ◽  
Electromagnetic Interference ◽  
Evaluation Method ◽  
Bragg Grating ◽  
Fibre Bragg Grating ◽  
Optical Fibre Sensors ◽  
Novel Approach ◽  
Reflected Light ◽  
Wide Range

Abstract. Optical fibre sensors cover a wide range of applications. They offer versatile advantages including resilience to electromagnetic interference, biocompatibility and chemical resistivity. Even in environments with restricted accessibility, integration difficulties can be overcome by using radio-over-fibre (RoF) technology that allows a wireless read-out. Conventionally, optical fibre sensors are evaluated in the optical domain by analysing the amplitude or spectrum of either the transmitted or the reflected light. A novel approach is to feed a radio frequency-modulated laser into the optical sensor and carry out a full electrical analysis of the resulting radio frequency (RF) signal, which is changed by the sensor's characteristics. This method will be investigated in this paper for fibre Bragg grating-based and chirped fibre Bragg grating-based sensors in reflection and transmission configuration. Their applicability for this new evaluation scheme will be discussed. Subsequent studies may cover additional types of sensors and the testing of the novel evaluation method within an application-related scenario, including packaging.

Sign in / Sign up

Export Citation Format

Share Document