7.3 Principles of Eye Diagrams
291
Fig. 7.15 The inclusion of
all possible signal distortion
effects results in a stressed
eye with only a small
diamond-shaped opening
Diamond-shaped
eye opening
sinusoidal jitter. The concept of this test is to assume that all different possible jitter
and intersymbol interference impairments that might occur to a signal in a fielded
link will close the eye down to a diamond shape, as shown in Fig. 7.15. If the eye
opening of the optical receiver under test is greater than this diamond-shaped area
of assured error-free operation, it is expected to operate properly in an actual fielded
system. The stressed-eye template height typically is between 0.10 and 0.25 of the
full pattern height. Chapter 14 gives more details on this stressed-eye test.
7.4 Burst-Mode Receivers
To address the continuously increasing demands by customers for higher-capacity
connections to a central switching facility, network and service providers devised the
concept of using a passive optical network (PON) [27–30]. Chapter 13 presents more
details of passive optical network configurations, which also have become known
as fiber-to-the-premises (FTTP) networks. In a PON there are no active components
between a central switching office and the customer premises (for example, homes,
businesses, or government facilities). Instead, only passive optical components are
placed in the network transmission path to guide the traffic signals contained within
specific optical wavelengths to the user endpoints and back to the central office.
Figure 7.16 illustrates the architecture of a generic PON in which a fiber optic
network connects switching equipment in a central office with a number of telecom
service subscribers. Examples of equipment in the central office include public telephone switches, video-on-demand servers, Internet protocol (IP) routers, Ethernet
switches, and network monitoring and control stations. In the central office, traditionally data and digitized voice are combined and sent downstream to customers over
an optical link by using a 1490-nm wavelength. The upstream (customer to central
office) return path for the data and voice uses a 1310-nm wavelength. Video services
are sent downstream with a 1550-nm wavelength. The transmission equipment in
291
Fig. 7.15 The inclusion of
all possible signal distortion
effects results in a stressed
eye with only a small
diamond-shaped opening
Diamond-shaped
eye opening
sinusoidal jitter. The concept of this test is to assume that all different possible jitter
and intersymbol interference impairments that might occur to a signal in a fielded
link will close the eye down to a diamond shape, as shown in Fig. 7.15. If the eye
opening of the optical receiver under test is greater than this diamond-shaped area
of assured error-free operation, it is expected to operate properly in an actual fielded
system. The stressed-eye template height typically is between 0.10 and 0.25 of the
full pattern height. Chapter 14 gives more details on this stressed-eye test.
7.4 Burst-Mode Receivers
To address the continuously increasing demands by customers for higher-capacity
connections to a central switching facility, network and service providers devised the
concept of using a passive optical network (PON) [27–30]. Chapter 13 presents more
details of passive optical network configurations, which also have become known
as fiber-to-the-premises (FTTP) networks. In a PON there are no active components
between a central switching office and the customer premises (for example, homes,
businesses, or government facilities). Instead, only passive optical components are
placed in the network transmission path to guide the traffic signals contained within
specific optical wavelengths to the user endpoints and back to the central office.
Figure 7.16 illustrates the architecture of a generic PON in which a fiber optic
network connects switching equipment in a central office with a number of telecom
service subscribers. Examples of equipment in the central office include public telephone switches, video-on-demand servers, Internet protocol (IP) routers, Ethernet
switches, and network monitoring and control stations. In the central office, traditionally data and digitized voice are combined and sent downstream to customers over
an optical link by using a 1490-nm wavelength. The upstream (customer to central
office) return path for the data and voice uses a 1310-nm wavelength. Video services
are sent downstream with a 1550-nm wavelength. The transmission equipment in