1 – 2
Overview
1.1
How to use this Manual
All users new to the LDC500 should begin with section 1.2 of this
chapter, to familiarize themselves with the basic architecture and
grounding scheme for the product. Section 1.6 provides an introduc-
tion to the user interface, and will also benefit new users.
Chapter 2 provides step-by-step examples for a new user getting
started with the LDC500, and is a good starting point for users al-
ready familiar with the basics of the user interface.
Chapter 3 provides a comprehensive treatment of the user interface
menu structure, with complete lists of all the parameter items.
Chapter 4 discusses remote operation of the LDC500, over RS-232,
GPIB, and ethernet. Many of the menu items discussed in chapter 3
refer to more detailed information here.
1.2
Introduction to the Instrument
The LDC500 Series Laser Diode Controllers are combination preci-
sion current source and temperature controllers. The current source,
intended to provide power to a laser diode (LD), provides a low noise,
high stability output with programmable current and voltage limits.
The temperature controller operates with most commonly used tem-
perature sensors and thermoelectric coolers (TEC) to maintain pre-
cision thermal control of the laser.Multiple remote interfaces–GPIB,
RS-232, and ethernet–give you complete control of the instrument
from your computer.
1.2.1
Instrument architecture
The LDC500 is logically divided into two functional sections, the
LD Driver and the TEC Controller, with a common control and in-
terface section for front-panel and remote operation. All three of
these sections are electrically isolated from each other, with only the
control
/
interface section electrically grounded to chassis ground.
A block diagram of the LDC500, showing the arrangement of
independently-isolated power sources, is given in Figure 1.1.
1.2.1.1 Laser diode driver
The primary function of the LD driver is providing stable, low-noise
electrical current to bias a laser into emission. This excitation is de-
livered by a low-noise current source circuit. The current source
has two range settings, with a maximum current commandable be-
tween 50 mA and 100 mA (LDC500), 250 mA and 500 mA (LDC501),
LDC500 Series Laser Diode Controllers
