SLD63509940X - Samsung Electronics

LASER DIODE

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■INTRODUCTION

Laser Diode (LD) is a semiconductor device with p-n junction which emit laser radiation by

applying a current in forward direction. The term laser is an acronym that stands for "Light

Amplification by Stimulated Emission of Radiation". The basic operating mechanisms of laser

diodes are similarly based on the electrical and optical properties of p-n junctions and

semiconductor materials. Laser diodes are devices emitting coherent light produced in a stimulated

emission process whereas LEDs under injection excitation emit light produced in a spontaneous

emission process. The light emission process in laser diodes is therefore more complicated than

that in LEDs. The materials used in laser diodes are quite similar to those used in LEDs, and the

lasing wave length ranges from the visible to the infrared wave length range depending on the

material of the active layer. The infrared 780 nm-band AlGaAs/AlGaAs and visible 635~650

nm-band AlGaInP/AlGaInP material systems are commonly used. Typical laser diodes emitting

visible light are composed of III-V compound semiconductors, but some II-Vi compound

semiconductors such as (Zn, Cd)Se/ZnSe are also used in laser diodes emitting visible light. On

the developmental stage of laser diodes, continuous-wave(cw) lasing at room temperature was

achieved in an AlGaAs/GaAs double-hetero structure has been a common one for laser diodes.

■FEATURE AND APPLICATION

●Feature

- The product is a semiconductor device with p-n junction which emit laser radiation by applying

a current.

- The product is widely used in IT/AV/Industrial application.

- Lasing wave length of this products are 780nm, 650nm and 635nm.

●Application

- Pointer

- Laser Printer

- Barcode Scanner & Measuring Instrument

- Data Storage & Optical Pick-up : CD-P, CD-ROM, CD-RW, DVD-P, DVD-ROM

LASER DIODE

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■STRUCTURE

LASER DIODE

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■PART NUMBERING

SLD 650 18 2 7 1 X

●

1●

2●

3●

4●

5●

6●

Samsung Laser Diode

Wave Length

Package Type

Optical Power

Operating Temperature

Pin Configuration

Suffix

●

1Abbreviation of SAMSUNG Laser Diode

●

2Wave Length

Symbol Wave Length

635 635㎚

650 650㎚

780 780㎚

●

3Package Type

Symbol Package Type

09 φ9.0㎜(TO-9 CAN)

18 φ5.6㎜(TO-18 CAN)

38 φ3.8㎜Small Package

※The suffix 'F' symbol shows the lead-frame mold type package. (Example: 78018261F)

●

4Optical Power

Symbol Optical Power

25㎽

37㎽

850㎽

990㎽

●

LASER DIODE

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●

5Operating Temperature

Symbol Optical Temperature

44℃

55℃

660℃

770℃

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6Pin Configuration

Symbol LD Lead ①PD Lead ②Drawing

0anode cathode

1anode anode

2cathode anode

●

7Suffix

This symbol shows the derivative parts.

LASER DIODE

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■PACKAGING

●Tray Packing

- Tray Packing Amount : 100EA LD/TRAY

- Tray Side Lot No. Marking : (Example)

Symbol 305 - 1

Meaning

Manufactured Month

(ex) 3 : March

A:October

C:December

MOCVD

(Epitaxial Growth)

Batch No. Wafer No.

●Box Packing

▶Inside Box ▶Outside Box

-Inside Box Packing Amount : 60EA TRAYS/INSIDE BOX (10EA : Capping Trays)

→5,000EA LD/INSIDE BOX

- Outside Box Packing Amount : 2EA INSIDE BOXES/OUTSIDE BOX

→10,000EA LD/OUTSIDE BOX

166㎜

240㎜

336㎜

LASER DIODE

362㎜

256㎜

350㎜

LASER DIODE

SLD65018371

LOT : 305-1

Tray Side Marking : (Ex.)

48㎜

oooooooooooooooooooo

168㎜

LASER DIODE

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●Labeling

▶Top View

▶Side View

ESD Warning Label

SLD65018371

Semco P/N

Customer P/N Production Lot Number

Customer P/N

LASER DIODE

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■APPLICATION MANUAL (OPERATIONAL ATTENTION)

●Operating Characteristics

Laser Diode (LD) is a semiconductor device with p-n junction which emit laser / strong

coherency / radiation by applying a current in forward direction. However, in difference from

usually semiconductor diodes LD have the next peculiarities:

1. LD usually operates at operation current 20~40mA for a low power LD and 80~120mA for

a high power LD and low applied forward voltage (usually ~2Ⅴ). But, very important

peculiarity of LD is high current densities (~2000~4000A/cm2) during LD operation.

Therefore, LD operation generates a significant heat thin active layer.

2. In normal operation mode, LD has a relatively small volume for laser output power (3~7mW

for low power LD and 25~220mW for high power LD). But, they have a very high density

of laser radiation in a active layer and on output mirror facet (~1.0MW/cm2 and more).

Therefore, there is a optical power limit caused by optical damage of output mirror facet /

COD (Catastrophic Optical Damage) /.

Fig.1 shows us typical COD phenomenon of laser diode. When you operate LD after

occurrence of COD, operating current at a specific power would be much higher than before

COD -Fig.1(b)-. In the worst case, laser power could not reach a required power due to

COD -Fig.1(c)-. When you drive LD, please pay attention to LD operation under COD power

level.

3. LD has a very quick electrical and light response (lower than a few nano-second and less).

In connection with these features LD are extremely susceptible to damage caused by

current surges. It must be stressed here that even an instantaneous application extra

pulse current causes a rapid LD's deterioration. Whenever, You handle LD, please pay

strict attention to the following precautions.

COD

Ith Iop

Operating Power

(a)

(b)

[ Forward Current (mA) ]

Regular Lasing After COD

High Iop

(c)

Regular Lasing

After COD

Low Power

Fig. 1 COD (Catastrophic Optical Damage)

LASER DIODE

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●Electrostatic Surge Prevention

Laser

Diode

MM C=200pF

Ⅴ

1 M O hm

A- Conductive floor mat

B- Conductive table m at

C - An tista tic s h oe s

D - Wrist s tra p

E- Grounded soldering iron

1 M Ohm

Fig. 3 Workbench for LD Operation

Fig. 2 Static Electricity Test Circuit

It is necessary to strike that LD are even more

sensitive to electrostatic discharge than Si-based

semiconductor chips and require more careful

preventive measures. COD also could be

happened by small surge due to electrostatic

discharge. Fig. 2 shows us a static electricity test

circuit of Samsung. When shipping the laser

diodes, they would be inserted in anti-static bags

to prevent electrostatic charging by transportation.

Example of a typical workbench for operation with

Laser Diode Fig. 3 :

1. Ground work tables and floors using

conductive table mats and floor mats;

2. Ground operators using conductive wrist

bands;

3. All used tools as well as soldering irons

should be ground

The grounding should be connected through a

resistor of approximately 1㏁.

●Precautions for Current Driving Circuits

1- AC Noise Filter; 2- Slow Starter; 3- APC Driver

AC100V

123

Fig. 4 General LD Operation Circuit

1. While operating, LD can be easily damaged by surge currents which may occur during power

on and off of the drive circuit or while adjusting the optical power output.

2. If possible, for standard testing process, we recommend to use the special industrial laser

diode current driver, for example, the Melles Griot current source 06 DLD 201 or other type.

3. When you use nonindustrial self designed drivers, please make it sure that the spike current

generated in on-off switching of power supplies does not exceed the maximum LD operation

current. It is recommended to insert an appropriate filter consisting of a appropriate CR circuit

LASER DIODE

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or other slow start circuit when chattering or overshoot shown in Fig. 4. Care must also be

taken to prevent surge currents from entering the circuit from external sources. Use an AC

noise filter.

Ith t

Pumping Pulse Current

Output Laser Power

Maximum

Power Rating

Fig. 5 LD Pulse Mode Operation

In pulse mode operation, overshoot in

optical power output is sometimes observed.

In this case, try to suppress the overshoot

or lower the overshoot power level below

the maximum LD operation current shown

in Fig. 5.

4. Make all electrical connections secure.

An open or short circuit while the LD is

on, will result in deterioration. It is

desirable to use shielded cables.

5. Use a reliable control for setting the operation current. Improper contacts may result in current

surges.

6. While LD is powered up, don't touch probes from a oscilloscope or volt-meter against the

circuit or LD terminals.

7. Don't CONNECT OR DISCONNECT the laser diode terminals while the POWER is ON.

●Heat Diffusion Precautions

1. All main LD's parameters depend on a temperature. Because of LD in operation during

generation of heat at the p-n junction/ active layer/ it is necessary to provide a good heat

conduction mechanism. Usually, LD chip is mounted on a heat sink within the package to

facilitate effective heat diffusion. Because the heat sink conducts the generated heat to the

package flange, it is advisable LD to attach a heat radiator to the LD package flange for

better heat diffusion. Thermal contact between the package flange and the heat radiator plate

must be good. Furthermore heat diffusion also depends on the design of the radiator plate, i.e.

, shape, size and material. An appropriate design is required for each industrial application.

2. Ineffective heat diffusion can cause a positive feed back of driving current and limit the

usability of the LD. Namely, high temperature of LD package reduces an optical output power

below an expected level, which requires higher driving current to maintain the nominal output.

As a result, this raises the temperature and requires more higher current. Thus excessive

driving current can destroy LD.

LASER DIODE

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●On the Safety of Laser Light

DANGER!

Visible Laser Radiation

Avoid Direct Eye Exposure

CLASS 3B LASER PRODUCT

Avoid to look into the laser light directly or directly

through an optical system. It is very DANGEROUS!

Samsung red and IR laser diodes correspond to the

class III B of the International Radiation Standard of

the Laser Products.

Although the typical optical output power of Samsung

low power laser ranges from a several mW to 5mW,

their power density can reach 1㎿/㎠. For observing laser beam safely, you always have to use

safety goggles that block infrared rays.

LASER DIODE

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■NOTICE

●Electrical & Optical Parameters & Definitions

Parameter Symbol Definition

Output optical power Pop Typical optical output power in pulse or CW mode. Up to this output

level, there are no kinks in the Light- Current curve.

Operating current Iop The forward current through the LD which necessary for the LD to

produce its specified typical optical output power

Operating voltage Vop The forward voltage across the LD by forward operating current

Wavelength λpThe wavelength of the laser spectral line with the greatest intensity

Watt-ampere

/ Slope / Efficiency SE The value of the incremental change in laser beam power for an

incremental change in forward current above the threshold current.

Monitoring current Im The monitoring photodiode current is proportional to LD laser output

power [ at a specified reverse bias voltage ]

Threshold current Ith The forward current value at which the LD begins to produce laser

output

Laser beam divergency

in horizontal plane θ//

The laser beam's full angular at the half-maximum intensity

points(FWHM), measured in horizontal plane [ parallel to the LD p-n

junction plane ]

Laser beam divergency

in vertical plane θ⊥

The laser beam's full angular at the half-maximum intensity

points(FWHN), measured in vertical plane

[ perpendicular to the LD p-n junction plane ]

LD reverse voltage VR Maximum admissible reverse bias voltage, which may be applied to

the LD without a damage

PD bias voltage VRp Maximum admissible reverse bias voltage, which may be applied to

the monitoring PD without a damage

Operating temperature Topr Range of the case temperature within which LD may be safety stored

Storage temperature Tstg Range of the ambient temperature within which LD may be safety

stored

Forward current If Current through the forward biased LD

Forward bias voltage Vf Laser diode voltage by an applied forward bias