Technical data

5-2

Operating Concepts

In this chapter, you can find basic information about instrument operation and measurement techniques

you can use with your Lightwave Component Analyzer.

The first two sections of this chapter cover different types of devices you can measure, and basic analyzer

operation and functions. Following these discussions are sections explaining important details of specific

analyzer functions.

The remaining sections explain measurement enhancement techniques, calibration, and GPIB operation.

Types of Devices You Can Measure

The lightwave component analyzer can measure four types of devices as a function of frequency. These

devices are categorized according to their input and output signals: electrical or optical. The lightwave

component analyzer can be thought of as both an optical and an electrical measuring instrument. The types

of devices the analyzer can measure are defined as follows:

• Optical-to-Optical (O/O) device: This is any device with an optical input and optical output signal. This

includes fiber cables, fiber cable connectors, couplers, splitters, tees, and so on.

• Electrical-to-Optical (E/O) device: This is any device with an electrical input signal and an optical

output signal. This includes E/O modulators or sources (often called E/O converters), directly

modulatable laser sources, transmitters, and optical modulators.

• Optical-to-Electrical (O/E) device: This is any device with an optical input signal and an electrical

output signal. This includes O/E demodulators or receivers (often call O/E converters), lightwave

receivers, and photo-diodes.

• Electrical-to-Electrical (E/E) device: This is any device with an electrical input signal and an electrical

output signal. This includes any type of device that is typically measured on an RF or microwave

network analyzer.

Lightwave Component Analyzer Operation

For either optical or electrical measurements, the operation of the lightwave component analyzer is similar

to an RF or microwave network analyzer. For electrical measurements the signal is split. The reference

signal goes directly into the analyzer and the test signal is applied to the device. The signal transmitted

through the device or the signal reflected back from the device’s input is measured. The ratio of the

transmitted or reflected signal to the reference signal is taken. The result is displayed on the analyzer

display as a trace value, where the X-axis is frequency and the Y-axis is magnitude.

For optical measurements, the same sequence is followed except that the electrical signal is used to

modulate a lightwave carrier. After being applied to the test device, the optical response signal is

demodulated. The response signal is the demodulated electrical signal.

In order to make these ratio measurements, an electrical source, a lightwave source, a lightwave receiver,

and an electrical receiver are required.