**1. Introduction**

Future optical communication systems will use the high bandwidth of optical fiber in the optical frequency domain. Fast transmitter and receiver modules are basic elements of these systems, which are able now to transmit terabits/s of information via the fiber. Experiments with opto-electronic integrated circuits (OEICs) in laboratory test beds and field tests require a special packaging that respects system requirements such as high environmental stability and low optical insertion loss. Several concepts for fiber-chip coupling schemes had been proposed in the past. One of these is laser micro welding shown by[1], [2], [3], [4], [5], [6], [7]. This scheme is referring to the standard for high volume industrial manufacture. The in‐ vestment costs for this laser welding equipment are considerably high. There are numerous proven techniques for aligning OEICs effectively. For laboratory use and rapid prototyping a flexible design is needed which is able to adapt different OEICs with changing dimensions to an existing module type.

In this chapter you will get general information what does opto-electronic packaging mean. Here fiber-chip coupling with basic coupling concepts will be illustrated. The different types of active adjusting and passive techniques are explained. Optical connectors play a very impor‐ tant role to interconnect different transmission systems. In passage 7 an overview of existing fi‐ ber connectors is shown. Afterwards, different optical module types for active and passive opto-electronic devices are described in details. Finally, the long-term stability of the modules must be tested and all reliability requirements for international test procedures are specified.

In its simplest arrangement, the packaging of OEICs involves the alignment and attachment of the light guiding areas of the OEIC and the optical fiber. At the beginning of this section, the basics of optical coupling theory with an introduction to optical mode fields and their matching by lenses is presented. Afterwards, a description of active and passive waveguide to waveguide coupling techniques will follow. Finally, optical connectors and the outline of

© 2013 Fischer; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 Fischer; licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

different kinds of start of the art optical modules will be depicted followed by a short over‐ view of long-term stability tests.

2

2

0

(1)

421

Opto-Electronic Packaging http://dx.doi.org/10.5772/51626

(2)

0

*w*

ì ü ï ï é ù

0

=

*w*

in figure 2, defines the mode field diameter.

**Figure 2.** Intensity distribution of the optical mode field.

*p p*

<sup>r</sup> (r) (0) exp 2

2 Mode field diameter(MFD)

2

( ) <sup>2</sup> *<sup>z</sup> wz w*

0 2

Here, the optical field within a wave-guide can be described nearly perfectly by a Gaussi‐ an intensity distribution, called p(r), which can be expressed with equation (1). If the wave travels within the waveguide, the mode field diameter is constant due to the com‐ bining function of the waveguide itself. At the end of the waveguide, the optical field is not guided and the field expands with increasing distance to the output facet. The expan‐ sion of the field can be calculated by equation (2). The point at which the intensity has fallen down to 1/e2 or 13.5% of the maximum intensity in radial direction, which is shown

After leaving the waveguide, the optical mode field radius, which is half of the spot-size, expands with increasing distance to the facet. For distances of less than 200 μm the field dis‐

é ù æ ö = + ê ú ç ÷ ê ú è ø ë û

*n w* l

p

= ´-í ý ê ú ï ï ë û î þ

At this point I would like to define the opto-electronic packaging which was given by [8]:

*"Opto-electronic packaging means working on the connection of opto-electronic integrated circuits to optical and electrical transmission lines and bias supply combined in a environmental stable housing."*

**Figure 1.** Basic package design for opto-electronic modules.

In the following several different technologies are listed which are essential to develop a new package:

