High-power handling, ultra-fast, GRIN lens-coupled photodetectors

Abhay Joshi; Don Becker; Shubhashish Datta

doi:10.1117/12.778485

24 March 2008 High-power handling, ultra-fast, GRIN lens-coupled photodetectors

Abhay Joshi, Don Becker, Shubhashish Datta

Proceedings Volume 6975, Enabling Photonics Technologies for Defense, Security, and Aerospace Applications IV; 69750R (2008) https://doi.org/10.1117/12.778485
Event: SPIE Defense and Security Symposium, 2008, Orlando, Florida, United States

Abstract

The performance of microwave photonic systems can be improved by utilizing high power handling photodetectors. Operation at higher photocurrents enables larger output RF signals to be produced directly by the photodetector. This reduces the requirement of signal amplification by RF amplifiers, thereby simultaneously improving the dynamic range and the noise figure. In optical coherent systems, high power handling photodetectors enable operation at high local oscillator power levels to boost the coherent gain and the detection sensitivity. Thus, techniques to enhance the power handling capability of photodetectors are of interest for both free space and fiber based applications. Photodetector current saturates at high optical power levels due to space-charge screening effect. The saturation effect is maximized where the illumination intensity, and the resulting photocurrent density, is largest. In this work, we focus on optimizing the optical field profile incident on top-illuminated InGaAs photodiodes to minimize the peak photocurrent density. This was achieved by employing graded-index (GRIN) lens coupling to uniformly distribute the optical power across the diode cross-section. We demonstrate 5dB improvement in photodiode's power handling capability and linearity by employing GRIN lens coupling as compared to single mode fiber (SMF) coupling. Our GRIN lens-coupled photodetectors have achieved small-signal 1dB compression current of >50mA and 12.5dBm amplifier-free RF output. These devices also exhibit linear behavior for a peak-to-peak RF pulse output of >2.5V, at ~30ps pulse width. This constitutes a 100% improvement over SMF coupled devices. Further, the GRIN photodiodes demonstrate pulse broadening =0.65ps/mW, as compared to 2ps/mW for SMF devices.

Citation Download Citation

Abhay Joshi, Don Becker, and Shubhashish Datta "High-power handling, ultra-fast, GRIN lens-coupled photodetectors", Proc. SPIE 6975, Enabling Photonics Technologies for Defense, Security, and Aerospace Applications IV, 69750R (24 March 2008); https://doi.org/10.1117/12.778485

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

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
8 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Photodiodes

GRIN lenses

Single mode fibers

Modulation

Photodetectors

Diodes

Indium gallium arsenide

Show All Keywords

Keywords/Phrases

Search In:

Publication Years