Chế tạo máy đo xa laer, an toàn cho mắt, bước sóng 1,54um, tần lặp 10 hz

yf • Hfli thto lCT.rda06 Proceedings of ICT.rda'06. Hanoi May. 20-21.2006

DESIGNING EYESAFE LASER RANGEFINDER

OPERATING AT 1.54 ^m AND 10 HZ-REPETITION

Che tao may do xa laser, an toan cho mat,

bir6rc song l,54^m, tan lap 10 Hz

Ho Quang Quy, Pham Vu Thinh, Nguyen Trong Tuan,

Le Thanh Hai, Tran The Anh, Tran Thai Binh

Abstract

In this paper we present the designs and development of eyesafe laser rangefinder

(ESLRF), operating at 1,54pm wavelength and withlOHz repetitive. Base on modern

technology and valuable and rare components, some important of ESLRF parts are

studied and designed. The operating principle and characteristical parameters of it are

presented in detail.

Keywords: Laser range finder, Eye-safe wavelengh, optical parametric oscillator, high

repetition

1. INTRODUCTION

A laser range-finder (LRF) is a device

that calculates the distance to target by

measuring the time it takes the laser light to

travel a round-trip path from the laser

transmitter to the target and back to the

receiver [3.9.10]. There are two typical

classes of LRF: pulse RLF that use direct

(incoherent) detection receivers and

modulated continuous wave (CW) LRF that

use heterodyne or coherent detection are

classified as laser radar [9]. The neodymium￾doped Yttrium Aluminum Garnet (Nd: YAG)

laser has been the work-horse of armed forces

world-wide for LRF applications since

replacing the ruby laser in late 1960s

[1,2,4,5].

Raman-shifted Nd: YAG, OPO-Nd: YAG

and erbium-doped glass (Er: Glass) lasers

were developed in the late 1970s to mid￾1980s as eye-safe alternatives to the Nd: YAG

laser [3,6-8,10,11]. These lasers also provide

improved performance in poor weather and

smoke and are expected to supplant the Nd:

YAG LRF for most single-function tactical

range-finding applications.

As a result, the Nd: YAG laser remains

the only laser in use today for designator

applications and has also become the basis for

all dual-function range-finder-designatoi

applications, with Raman shifting and optica!

parametric oseillator-OPO providing £

compatible eye-safe (>1.5p.m) mode foi

range-finder and training.

One of important parts of LRF is the lasei

receiver, which consists of sensitivit)

photodiode and electric circuit. To increasE

the sensitivity and decrease the noise oi

receiver, operating at convenience

wavelength, a lot of missions have beer

investigating. Till now, a lot of classifiec

photodiodes have been produced, bu'

investigating in detail to use them for LRF

remains a complicated question[15]

Furthermore, many optical systems, as

telescope, narrow band filter, going togethei

the eye-safe-wavelength transmitter anc

receiver must be provided.

In this report we present the principle o:

eye-safe LRF, design of some important o;

LRF parts by modem technology and valuabk

rare components, characteristical parameters.

2. OPERATION PRINCIPLES

2.1. Operation principle

The operating principle of ESLRF is

described in Fig. 1.