Integrated optics devices

1. Ameer H. Ali

2. Outlines
 Integrated Optical (IO)
 Technical Limitations
 Advantages

3. Integrated Optical (IO)
Integrated technology for optical devices has developed within optical
fiber communications so that it is now possible to fabricate a complete
system onto a single chip.
containing several or many optical components which are combined to
achieve some more or less complex functions. Example of Integrated
optical devices are optical filters, modulators, amplifiers and
others. They can, e.g., be fabricated on the surface of some crystalline
material (such as silicon, silica)and connected with waveguides.

4. Introduction
The original idea of integrated optics came from the technology of
electronic integrated circuits, which has shown rapid development
over several decades and has led to amazing achievements, such as
complex and powerful microprocessors containing many millions of
transistors, specialized signal processors and computer memory chips
with huge data storage capacity. Unfortunately, integrated optics has
not been able to match the progress of microelectronics in terms of
the complexity of possible devices. This results from a number of
technical limitations:

5. Technical Limitations
 The electronic circuits can contain extremely small wires, but in the
optical components need to be connected via waveguides, the
dimensions of which usually cannot be much smaller than the
wavelength, and which often cannot tolerate very sharp bends.
 Optical connections, e.g. between waveguides, and couplers are
significantly more difficult than electrical connections.

6. Technical Limitations
 Waveguides, device connections and passive optical components
exhibit optical losses, which often need to be compensated with
optical amplifiers. These are larger and more complex than electronic
amplifiers based on transistors.
 Some types of optical components are difficult to minimize.

7. Technical Limitations
For these reasons, integrated optical circuits have not reached by
far the complexity of electronic integrated circuits. However,
devices of moderate complexity can still be useful for example for
optical fiber communications, where they can host multiple data
transmitters and/or receivers, consisting of distributed feedback
lasers, optical modulators, photodiodes, and optical filters.

8. Advantages
 The use of optical fiber offers the possibility of high-speed
operation and faster than that employing electronic circuits.
 the ability to utilize optical fiber of different frequencies (or
wavelengths) within the same guided wave channel or device.
hence, this possibility for powerful parallel signal processing
coupled with ultra high speed operation offers tremendous
potential for applications within both communications and
computing.

9. Optical-Fiber couplers
 couplers are a basic element of many optical fiber communication
systems , often perform a distribute or combine in many branch
fibers.

10. Amplifiers
An optical amplifier is a device that amplifies an optical signal
directly, without the need to first convert it to an electrical signal.
Optical amplifiers are important in optical communication . They
are used as optical repeaters in the long distance fiber optic cables
which carry much of the world's telecommunication links.
The most practical amplifiers to data include:
1- semiconductor optical amplifier SOA.
2- Erbium Doped Fiber Amplifier EDFA.

11. Fiber-optic filter
Fiber-optic filter is an optical fiber instrument used for
wavelength selection, which can select desired wavelengths to
pass and reject the others.
types of optical filter :
1- Fabry-perot Filter
2- Fiber Bragg Gratings Filter

12. References
[1] Optical Fiber Communications Principles and Practice Third Edition, JOHN M.
SENIOR.
[2] Fiber-Optic Communication Systems Third Edition, GOVIND P. AGRAWAL