Signal-to-noise ratio of arbitrarily filtered spontaneous emission

Marko Šprem; Marko Bosiljevac; Dubravko Babić

doi:10.1117/12.2289090

23 February 2018 Signal-to-noise ratio of arbitrarily filtered spontaneous emission

Marko Šprem, Marko Bosiljevac, Dubravko Babić

Proceedings Volume 10526, Physics and Simulation of Optoelectronic Devices XXVI; 1052621 (2018) https://doi.org/10.1117/12.2289090
Event: SPIE OPTO, 2018, San Francisco, California, United States

Abstract

The signal-to-noise ratio (SNR) of filtered incoherent light can be approximated from the product of the coherence time of the light and the equivalent (electrical) noise bandwidth of the detector. This approximation holds only for the light with very short coherence time, that is in the case where the optical bandwidth of the light is much larger than the electrical bandwidth. We present here an expression for accurate evaluation of the SNR of the filtered incoherent light, which computes SNR from arbitrary shapes of optical and electrical filter power spectral densities (PSD). The PSDs of the filters can be measured using optical and electrical spectrum analyzers. Using our expression, we show that the SNR reaches unity when the electrical filter bandwidth is becoming larger than the optical filter bandwidth. To prove the theory, we evaluate and directly measure SNR of an incoherent light source filtered with several optical filters with bandwidths larger and commensurate with the bandwidth of the detector. For later we used optical and electrical filters with 3-dB bandwidths of 15 GHz and 10 GHz, respectively. Using our expression to evaluate SNR we obtained results in a good agreement with directly measured SNR. The results also prove that the approximation for evaluating SNR does not provide accurate results. The PSD of the detector with large noise bandwidth is difficult to measure using spectrum analyzer. There- fore, we report here a method for measuring the electrical noise bandwidth of the detector using the heterodyne linewidth measurement technique with tunable laser.

Citation Download Citation

Marko Šprem, Marko Bosiljevac, and Dubravko Babić "Signal-to-noise ratio of arbitrarily filtered spontaneous emission", Proc. SPIE 10526, Physics and Simulation of Optoelectronic Devices XXVI, 1052621 (23 February 2018); https://doi.org/10.1117/12.2289090

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available