Project TitleOrganic Electro-Optic Modulators with Transparent Electrodes and Device Structures
Track Code2008-155
Short Description

A novel construction for electro-optic (EO) modulators and related devices.

#communications #wireless #devices #optoelectronic


Northwestern researchers have developed a novel construction for electro-optic (EO) modulators and related devices.  EO optical intensity modulators are widely used in optical fiber communications to modulate light from semiconductor lasers to produce the required optical pulses carrying digital data for transmission. At high modulation rates (above 10 Gbits/sec), a frequency chirped pulse (change in the lasing frequency at the leading and trailing edges of the pulse) will be rapidly broadened in width after propagating through a long length of optical fiber causing serious degradation in the signal integrity. Thus, external optical intensity modulators are needed for long distance optical communications at bit rates at or above 10 Gbits/sec.  Current commercially-available high-speed EO optical intensity modulators are based on lithium niobate crystals and require about 0.5 W of electrical power, which is high and quite inefficient in terms of electrical-to-optical signal-power conversion for typical semiconductor laser power.  While there is much interest in reducing the modulator driving voltage, current modulator designs and component materials tend to limit further advances in performance. The present invention provides electro-optic modulators and related devices that address these shortcomings.  The researchers have designed a modulator that utilizes organic electro-optic materials with exceptionally high EO coefficients.  By incorporating transparent conducting oxide electrode bridge components and horizontal optical mode confinement with optimized electrical and optical characteristics, it exhibits lower switching power and a compact device structure.  This combination of design and materials promise significant advancement for long distance optical communications at 10 Gbits/sec bit rates and above.

TagsCOMMUNICATIONS: wireless, DEVICES: optoelectronic
Posted DateMay 4, 2011 3:44 PM


Tobin Marks*

Seng-Tiong Ho

Fei Yi


  • Long distance optical communications


  • Lower switching voltage
  • Improved performance
  • Compact structure

IP Status

Issued U.S. Patent 8,644,648

Contact Information

Zach Brown, PhD

Invention Associate

(p) 847-491-4629