Limits to Maximum Absorption Length in Waveguide Photodiodes
Abstract
The maximum photocurrent, power dissipation, and Iinearity of waveguide photodiodes are limited by the length over which the input optical power is absorbed. This absorption length is determined by the absorption coefficient of the absorbing layer material (a0), the optical confinement factor (r), and the excess optical loss (ai). In this work, we analyze the fundamental limits to maximizing the absorption length and demonstrate a new waveguide photodiode structure that approaches these limits. The new structure is referred to as a slab-coupled optical waveguide photodiode (SCOWPD) and is realized in the InGaAsP/InP material system. Assuming 100% coupIing efficiency, the SCOWPD has an ultra-low optical confinement factor and low excess optical loss, both calculated from measurements, of r = 0.069% and ai = 1.65 cm^-1, respectively. This results in a 1/e absorption length of 2.1 mm. The SCOWPD exhibits an external responsivity of 0.8 A/W and a maximum photocurrent of 250 mA at a wavelength of 1.55 um.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 13, 2011
- Accession Number
- ADA569713
Entities
People
- Antonio Napoleone
- Douglas C. Oakley
- Jason J. Plant
- Jonathan Klamkin
- P Juodawlkis
- Shannon M. Madison
Organizations
- Massachusetts Institute of Technology