Featured Research

from universities, journals, and other organizations

Enabling next-generation wireless networks

Date:
March 13, 2014
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
A modulator that converts an electrical signal into an optical signal could enable faster wireless data transmission. Wireless transmission at microwave frequencies is important for high-data-rate transmission applications, such as mobile phone networks, satellite links and remote imaging. Now, scientists have investigated different designs of silicon modulator that enable fast data conversion from electrical to optical signals.

A typical modulator consists of two optical waveguides etched into a silicon chip.
Credit: Copyright 2014 A*STAR Institute of Microelectronics

A modulator that converts an electrical signal into an optical signal could enable faster wireless data transmission.

Wireless transmission at microwave frequencies is important for high-data-rate transmission applications, such as mobile phone networks, satellite links and remote imaging. Now, Xianshu Luo and colleagues from the A*STAR Institute of Microelectronics in Singapore have investigated different designs of silicon modulator that enable fast data conversion from electrical to optical signals.

A key component in a microwave photonic network is the modulator, which converts an electrical signal into an optical signal. "The performance of the microwave photonic system relies on the quality of this conversion, which is determined by factors such as loss, noise and signal distortion," explains Luo. As the modulator acts a bridge between optical components and silicon-based electronics, it should be fabricated on a silicon chip.

The researchers built their modulators according to standard specifications used for semiconductor electronics. A typical modulator consists of two small channels for light -- so-called waveguides -- etched into a silicon chip (see image). Light is fed into a waveguide on the chip, which then splits into two; modulation occurs when these two beams are reunited. If the light passing through one channel is delayed slightly compared to that in the other channel, the signals from both beams will either cancel each other out or reinforce each other. This property is used to generate the '0' and '1' signals for digital transmission.

In silicon modulators, light transmission in one waveguide is delayed by applying a radio signal, which results in electrical charges either being added to or removed from the material surrounding the waveguide. This addition or subtraction of charge modifies the optical properties of silicon.

Modulators based on the addition or removal of electrical charges have different attributes. While the initial injection of electrical charge carriers -- charges that are free to move -- is fast in modulators based on the addition of charges, the carrier recombination takes time, which slows down the overall speed. Modulators that have electrical carriers removed, reducing the nonlinear optical effects, experience less noise in the modulated signals.

The different characteristics of the two types of modulator mean that they are suited to different applications, and the researchers' experiments are helping to inform this choice. Both designs are capable of fast speeds, with the devices under test having an operation bandwidth of about 10 gigahertz, according to Luo. "More recently we have demonstrated similar modulators with even larger bandwidths of up to 28 gigahertz, which means that they can work at even faster rates of data transmission," he says.


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Xianshu Luo, Xiaoguang Tu, Junfeng Song, Lu Ding, Qing Fang, Tsung-Yang Liow, Mingbin Yu, Guo-Qiang Lo. Slope efficiency and spurious-free dynamic range of silicon Mach-Zehnder modulator upon carrier depletion and injection effects. Optics Express, 2013; 21 (14): 16570 DOI: 10.1364/OE.21.016570

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Enabling next-generation wireless networks." ScienceDaily. ScienceDaily, 13 March 2014. <www.sciencedaily.com/releases/2014/03/140313092521.htm>.
The Agency for Science, Technology and Research (A*STAR). (2014, March 13). Enabling next-generation wireless networks. ScienceDaily. Retrieved August 30, 2014 from www.sciencedaily.com/releases/2014/03/140313092521.htm
The Agency for Science, Technology and Research (A*STAR). "Enabling next-generation wireless networks." ScienceDaily. www.sciencedaily.com/releases/2014/03/140313092521.htm (accessed August 30, 2014).

Share This




More Matter & Energy News

Saturday, August 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins