A 11 ID 3 lETt.75 NIST

PUBLICATIONS

m/m

NISTIR 89-3917

IMPROVED LOW-LEVEL

SILICON-AVALANCHE-PHOTODIODE

TRANSFER STANDARDS AT

1.064 MICROMETERS

A.L. Rasmussen

RA. Simpson

A.A. Sanders

National Institute of Standards and Technology

U.S. Department of Commerce

Boulder, Colorado 80303-3328

August 1989

—QC

100

• U 56

89-3917

1989

C.2
NATIONAL INSTITUTE OF STANDARDS &

TECHNOLOGY

Research Information Center

Gaithersburg, MD 20899

DATE DUE

Demco, Inc. 38-293
NISTIR 89-3917

IMPROVED LOW-LEVEL

SILICON-AVALANCHE-PHOTODIODE s

TRANSFER STANDARDS AT

1.064 MICROMETERS

A.L. Rasmussen

RA. Simpson

A.A. Sanders

Electromagnetic Technology Division

Center for Electronics and Electrical Engineering

National Engineering Laboratory

National Institute of Standards and Technology

Boulder, Colorado 80303-3328

August 1989

U.S. DEPARTMENT OF COMMERCE, Robert A. Mosbacher, Secretary

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, Raymond G. Kammer, Acting Director

CONTENTS

Page

ABSTRACT 1 INTRODUCTION 1

1 . APD TS System Description 5

2. Warning When Using the APD TS System 7

3. APD TS System Parts . 7

4. Power Supplies 8

5. Setup 8

6 . Operation 9

7. Making APD TS Measurements 10

8. Shut-Down 10

9. APD TS Equipment 10

10. Calibration Procedures 11

11. Acknowledgments 14

12. References 14

iii

Improved Low-Level Silicon-Avalanche- Photodiode Transfer

Standards at 1.064 Micrometers.

A.L. Rasmussen, P.A. Simpson, and A. A. Sanders

Electromagnetic Technology Division

National Institute of Standards and Technology

Boulder, Colorado 80303

Three silicon-avalanche-photodiode (APD) transfer standards were

calibrated from ~10” 8 to ~10-5 W/cm2 peak power density at

approximately 10% uncertainty. These calibrations are for 1.064 fj,

m

wavelength pulses of 10 to 100 ns duration. For this calibration,

an acousto-optically modulated laser beam generated alternately

equal levels of pulsed power and cw power into a low-level beam

splitter. The cw power measured by a transfer standard in the

transmitted beam of the splitter was used to determine the pulsed

power into the APD transfer standard in one of the low-level

reflected beams of the splitter. The APD detector had about a 1 cm2 aperture and a 3.8 cm focal length lens in front of it. Lens,

window, and detector surfaces had narrow-band antireflection

coatings. The commercial detector package is a temperature

compensated, infrared- enhanced APD preamplifier module. To

increase the sensitivity, one or two 20 dB , 500 MHz bandwidth

amplifiers followed the preamplifier. With very low pulsed power,

a 30 MHz low-pass filter with Gaussian roll-off was attached to the

amplifier output to reduce the noise. A transient digitizer

recorded the impulse responses of the APD detectors at 1.064 fim.

These data were read into computer programs that convolved the

unit-area impulse response with unit-height Gaussian pulses. From

these data, correction factors of the pulse peak for observed pulse

durations from 10 to 100 ns were determined. Instructions,

calibrations, error budgets, and system descriptions are included.

Key words: detector impulse response; laser pulse detectors; laser

pulse standards; low-level pulse detectors; pulse power

measurements; YAG laser pulse calibrations

INTRODUCTION

Laser designator and range-finder applications have prompted the development

of low-level transfer standards at the National Institute of Standards and

Technology. The three silicon-avalanche-photodiode transfer standards (APD

TS) described in this report have improved sensitivity, stability and

accuracy over previous APD transfer standards [1] , [2] , [3]

.

Table A,

Characteristics of Silicon-Avalanche-Photodiode Transfer Standards (APD TS)

,

and the section that follows give details about these detectors.

1
DISCLAIMER

Certain commercial equipment, instruments, and materials are

identified in this publication in order to explain the experimental

procedure adequately. Such identification in no way implies

approval, recommendation, or endorsement by the National Institute of

Standards and Technology, nor does it imply that the equipment,

instruments, or materials identified are necessarily the best

available for the purpose.

2
TABLE A. Characteristics of Silicon-Avalanche- Photodiode

Transfer Standards (APD TS)

Parameter

Noise

Range

Responsivity

Collector lens

Detector

20 dB and 40 dB

(two 20 dB units)

amplifiers

(follow preamplifier)

Characteristics

-4 x 10” 9 W/cm2

-10” 8 to -10” 5 W/cm2

1. Manufacturer's temperature

coefficient of responsivity

-0.1% /°C using temperature

compensation circuit.

2. Temperature controller

35°C ± ~0.25°C used when

environment is severe.

1. Narrow-band 1.064 /zm antireflection

coating on surfaces.

2. Planoconvex lens with FL 3.8 cm

and OD 2.5 cm.

3. Aperture in front of lens approximately

1 cm2

. 4. Lens and detector separated so that

collimated beam is a little defocused at

the detector. Lens position is read on

the scale adjacent to the lens holder,

and it is held with a locking nut.

1. Narrow-band 1.064 /im antireflection

coated window and detector.

2. APD-preamplif ier module.

3. Dimples in surface of detector to

increase internal reflection of beam.

4. Detector uniformity eliminates need for

diffuser

.

5. Diameter of detector 0.3 cm.

1. -3 dB BW 500 MHz

2. 20 dB gain (noninverting)

DC to 300 MHz

3 . Input and output impedance 50

4. Dynamic range 72 dB

.

5. Rise and fall times 0.6 to 0.75 ns.

6. Equivalent input noise, 10 Hz to 500 MHz

BW, 20 /xV.

7. Second and third harmonic distortion

-60 dBc (max -50 dBc)

Gaussian roll-off

Lowpass

3 dB cut-off frequency, 30 MHz.

30 MHz filter

(follows amplifiers

when used)

1 . 2 . 3.

3
'

.
1. APD TS System Description.

These transfer standards will measure ~10” 8 to 10” 5 W/cm2 peak power

density of ~10 to 100 ns duration pulses at 1.064 /zm wavelength. See

figure 1

.

The detector package is a specially ordered commercial unit. An

antireflection coated lens and fixed aperture are mounted in front of

the 3 mm diameter detector, which has an antireflection coated

window. The complete unit is housed in a black box with attached

legs and platform.

Power supplies are provided for the detector, preamplifier,

amplifiers, and temperature controller. Temperature compensation in

the detector package maintains the responsivity with negligible

change over a broad temperature range. The temperature controller

was designed to maintain the detector at a given temperature when

needed

.

The detector unit is a temperature compensated silicon-avalanchephotodiode preamplifier module. The detector is IR-enhanced and has

an array of dimples on its surface. These dimples and an

antireflection coating on the detector surface increase the signal

absorption and responsivity. Because of the dimples the responsivity

will show nonuniformity when the surface is scanned with a very small

beam. Using a 0. 3-0.4 cm diameter beam that was focused to a small

spot, we calibrated the detector at the center of the surface. It

5
was also calibrated at seven mathematically selected locations 1 on

the surface to determine the uniformity of the responsivity with the

given beam. APD 721 and APD 723 were rotated 45° and calibrated at

seven locations again.

From these data the center calibration was given a correction factor

and uncertainty for the uniformity.

When a ~ 10 cm diameter, stable, uniform, collimated LED beam was

directed into the detector with 0.5 cm2 and 1 cm2 apertures, the

detector output was proportional to the area of these apertures. The

responsivity of the detector was uniform to these larger beams.

To increase the sensitivity of detection, one or two amplifiers are

attached to the preamplifier output. These may be followed by a

30 MHz low-pass filter with Gaussian roll-off to reduce noise and to

measure ~10‘ 8 w/cm2 peak power density of -20 ns duration pulses.

Since the filter lengthens the impulse response time of the system,

the correction factor for the peak voltage changes accordingly.

At 1.064 ^m correction factors for peak voltage at the observed pulse

duration are given for 0 dB, 20 dB (with and without the 30 MHz lowpass filter) , and 40 dB (with the 30 MHz low-pass filter)

'Handbook of Mathematical Functions, U.S. Department of

Commerce, National Bureau of Standards, AMS 55. Edited by

M. Abramowitz and Irene A. Stegun, June 1964, p 892. Weighted

average of seven points in circular area with h = 0.4 cm was the

same as the average of the seven values. Rotating the detectors

45° and taking seven more points yielded similar averages.

6
2. Warning When Using the APD TS System

a. Stay within the power and voltage ranges in the table of the

APD TS system.

b. Do not exceed these limits for you can burn out components

in the APD TS system and cost considerable expense and time

to repair, replace, and recalibrate.

c. Do not disassemble the APD TS for you can ruin its

calibration.

d. Operate the APD TS in a darkened room to prevent instrument

damage and erroneous measurements.

e. Observe input/output connections of amplifier(s) and the

30 MHz low-pass filter.

f. Stay within the ranges given for the amplifiers. You can

damage them if you exceed these limits. Also, just slightly

exceeding these limits can introduce subtle errors.

3. APD TS System Parts.

a. APD TS with built in lens and aperture.

b. Alignment mirror and iris.

c. Two lens mount sleeves.

d. Detector bias power supply.

e. Preamplifier bias power supply.

f. Temperature controller power supply.

g. Temperature measuring equipment (digital voltmeter provided

by user)

.

h. Ungrounded precision voltmeter (provided by user).

i. Two 20 dB amplifiers with power supply attached.

j . 30 MHz filter.

k. Cables.

7
4. Power Supplies

a. Preamplifier bias power supply, ± 9.0 V.

b. Detector bias power supply, + 550.0 V. Turn on or off by

gradually increasing or decreasing voltage.

c. Temperature controller power supply, + 15 V (not generally

used because temperature compensator circuit of the detector

maintains a calibration that changes negligibly over a broad

temperature range)

5 . Setup

a. Do not connect the temperature controller power supply and

temperature meter to the detector unless temperature control

is needed.

b. If you need temperature control, connect the temperature

controller to the detector, and a digital ohmmeter

(operating temperature reading about 3.5 kQ) to the

temperature meter terminal of the detector.

c. Attach detector bias power supply to the detector + 550.0 V

terminal and to an ungrounded precision voltmeter (furnished

by user)

d. Attach preamplifier power supply to the appropriate terminal

of the detector using the flexible grey cable.

e. Attach output terminal of the detector to a 7A24

oscilloscope plug-in of a 7904 oscilloscope or equivalent

for 0 dB gain measurements or to the 20 dB amplifier for

20 dB gain or the two 20 dB amplifiers in series for 40 dB

gain. Attach amplifiers in order of serial numbers given in

calibration tables 1-3, see footnote f.

8
f. For lower noise attach the 30 MHz low-pass filter to the

output of the amplifier (s)

.

g. For wider bandwidth attach the 20 dB amplifier with serial

number given in the calibration tables 1-3, see footnote f,

without the 30 MHz low-pass filter.

h. Attach the amplifier or 30 MHz low-pass filter output to the

oscilloscope plug-in.

i. Observe input/output connections of amplifier(s) and the

30 MHz low-pass filter.

6 . Operation

a. Turn on preamplifier power supply.

b. Turn on detector bias power supply, gradually increasing

voltage until it reads exactly the operating voltage. Return

the voltage to zero in a like manner when shutting off

equipment

.

c. Turn on amplifiers being used, and disconnect and turn them

off when changing or shutting off equipment.

d. Remove the alignment mirror from the detector.

e. Blow dust off the APD collector with a squeeze-type air

blower ONLY (other types such as those in spray cans may

spray liquid and damage the surface)

.

f. Reattach the alignment mirror and attach the iris.

g. Align the APD TS in a visible or 1.064 /im beam with the beam

returning on itself, or

h. Using a collimated beam, align the APD TS without the

alignment mirror and iris by positioning it for maximum

pulse height at a gain and range given in the calibration

table

.

9
7

Making APD TS Measurements

a. Set a baseline of two divisions and a pulse height of three

to five divisions.

b. Refer to tables 1, 2, 3, and 4 for gain, calibration, range,

and uncertainty.

c. Read the peak voltage and the observed pulse duration

(FDHM)

d. Find the corrected peak voltage by multiplying the observed

value by the correction factor in figures 2 through 13.

e. Divide the corrected peak voltage by the calibration in

column 1 of tables 1, 2, or 3 to get the power density

(W/cm2

)

f. Acquire enough data for significant statistical information.

8.

Shut-Down

a. Disconnect and turn off the amplifier(s)

b. Gradually decrease the voltage of the detector bias power

supply to zero and turn the power supply off.

c. Turn off the preamplifier power supply.

d. Reattach the alignment mirror to the APD TS to protect the

collector of the detector.

9APD TS Equipment

a. APD detector bias power supply, Bertan Assoc. Inc., Model

602B-15P.

b. Precision digital voltmeter for detector bias voltage

measurement

c. CLC100 linear amplifiers, Comlinear Corporation.

10
d. Oscilloscope readout, Tektronix 7904, NIST 145935 (used at

NIST) .

1. APD readout, dual trace amplifier, 7A24, 5012.

2. Dual time base, 7B92A.

e. Preamplifier bias power supply (NIST made).

f . Temperature controller power supply (NIST made)

.

g. Low-pass filter, 3 dB cutoff frequency 30 MHz, Gaussian

roll-off; Reactel, Inc., Model 7LX4-30-B21.

10. Calibration Procedures

a. Responsivity

.

Procedures for calibrating responsivity have been described in

several publications [1-4], and are briefly reviewed here. An

acousto-optically modulated cw 1.064 /im laser beam in the TEMQO mode

generates alternately equal levels of pulsed power and cw power into

a low-level beam splitter. The cw power measured by a transfer

standard in the transmitted beam of the splitter is used to determine

the pulsed power into the APD transfer standard in one of the

reflected beams of the splitter. The calibration factor is found by

dividing the peak output voltage by the pulsed power per aperture

area of the APD collector.

b. Impulse response related corrections of the peak voltage of

the APD transfer standards.

A transient digitizer recorded the impulse responses of the APD

transfer standards. These data were read into computer programs that

convolved the unit-area impulse response with unit-height Gaussian

pulses of various selected durations. From these data, correction

factors of the pulse peak for observed pulse durations from 10 to

100 ns were determined.

11
Inserting a 30 MHz filter in the detector system reduces noise and

increases sensitivity. However, the correction factor for the peak

voltage and its uncertainty also increase, especially for the shorter

pulses. See correction factor curves, figures 2 through 13.

Use the following measurements and equations to calibrate directly

the correction factor for the peak voltage with the 40 dB amplifier

and 30MHz filter: (1) Measure peak power near the bottom of the

range with the 20 dB amplifier and no filter and (2) Determine the

correction factor for the peak voltage with the peak power unchanged

and near the top of the range with the 40 dB amplifier and the 30 MHz

filter

Apply the following equations:

^2 0 Vp2 0 W

P =

k2 o

near the bottom of the range with the 20 dB amplifier and no filter

where

W

p = peak power in watts

CF20 — correction factor of peak voltage with 20 dB amplifier

(see figs. 2-13)

Vp20 = peak voltage reading with 20 dB amplifier

K20 = calibration factor with 20 dB amplifier (see tables 1, 2,

or 3 , column 1 )

and

w

p = CF40F Vp40F

KA 0 F

12
near the top of the range with the 40 dB amplifier and the filter

where

W

p = peak power, as before

CFAO f = correction factor of peak voltage with 40 dB amplifier

and 30 MHz filter (to be calculated)

Kaof = calibration factor with 40 dB amplifier and 30 MHz

filter (see tables 1, 2, or 3, column 1)

Vp ^ o f ~ P eak voltage with 40 dB amplifier and 30 MHz

filter corresponding to an observed pulse duration.

From these equations we get the correction factor

W

p 0 F

Vp4 OF

If the laser pulse maintains its shape, then CFaof is constant

over the range of the detector with 40 dB amplifier and 30 MHz

filter

.

Curves of correction factor of peak voltage versus observed pulse

duration for identical gain and measurement parameters are very

repeatable. However, correction factors at the highest peak power

range (0 dB) differ for changes in level of the Gaussian impulse

response. These differences diminish rapidly with increased pulse

duration. See tables 5, 6, and 7. They are due to load differences

when changing gain settings of the transient digitizer during impulse

response measurements.

For a given gain and set of measurement parameters of APD 721, the

convolution of the impulse response with Gaussian, skewed Gaussian,

and cosine-squared input pulses at a given observed pulse duration

13
yield approximately the same correction factors of the peak voltage.

See tables 8 through 11. Convolution with triangular and rectangular

(not shown) input pulses yield more scattered correction factors of

the peak voltage from the above.

11. Acknowledgments

The authors thank J.J. Skudler for designing and fabricating transfer

standard components. They also thank the Aerospace Guidance and

Metrology Center, Newark Air Force Station for funding this work.

12. References

[1] Sanders, A. A.; Rasmussen, A. L. A system for measuring energy and

peak power of low-level 1.064 ^m laser pulses. NBS Tech. Note 1058

(1982)

[2] Rasmussen, A. L. ; Sanders, A. A. Transfer standards for energy and

peak power of low-level 1.064 micrometer pulses and continuous wave

laser power. Optical Engineering 25(2), 277-285; 1986 February.

[3] Rasmussen, A. L. ; Sanders, A. A. Documentation of the NBS APD and

PIN calibration systems for measuring peak power and energy of lowlevel 1.064 fim laser pulses. NBSIR 85-3032, 1985 December.

[4] Rasmussen, A. L. ; Franzen, D. L. Low-level germanium detector

transfer standard at 1.064 /im. NBSIR 85-3041, 1986 January.

14
TABLE

1.

APD

721

SYSTEM

CALIBRATION*

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15
TABLE

2.

APD

723

SYSTEM

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TABLE

3.

APD

725

SYSTEM

CALIBRATION*

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G P PQ G3 P 'G

O

G

«—H • LO CO o P G rH o o

cti

m <r P o O •rH

O • •H

u > • • • •H P ON o CM <p vt o p

rH t-H t-H i—1 G I''-

a

G fa /* S /-sG

O < X r-H CM CO P

/^\

—vrN

H

N ' P

r-H CM CO -X

O '—

•X * H

o awGP

t-H o

CM

ON

ONo

0)bO

cOP II a)

17

Uniformity

calibration

average/

Center

of

detector

calibration

av

for

APD

721,

APD

723,

and

APD

725
TABLE 4. Error budget APD 721, APD 723, and APD 725 system.

Source of error Uncertainty %

Redw 3 transfer standard( identifying designation

to commercial instrument) , S 1 1.9

Beamsplitter attenuator, S 2

CN

Equivalence of pulsed and cw power, S 3 2.5

Oscilloscope readout, S A 3.0

Correction factor of peak voltage for

OBS At (observed pulse duration) >15 ns, S 5 3.0

r"

'

\l 5

V s S i 2 /3

1 3.37

Precision and uniformity, (SD)/\/n:

(SD) 1 /y/n 1 (APD 721), (SD) 2 />/n2 (APD 723), and (SD) 3 /Vn3 (APD 725)

1.38, 0.88, 0.37 resp.

Total uncertainty for APD 721, APD 723, and APD 725:

(SD) 2 /n+S

1

S

2 /3 = 10.9, 10.5, 10.2 resp

18
TABLE 5. Percent deviation of average CF V

p

* from CF V

p

data of individual

runs (see Fig. 2)

APD 721 - 0 dB - No Filter

Input

Gaussian

pulse

duration

ns

Average

CF V

p *f

of runs

9 & 10

Average

OBS At* * f o f runs

9 & 10

Percent Impulse response

deviation of peak voltage

average CF V

p

* from CF V

p

of runs 9 & 10

10 0.961 9.6 ± 1.4

15 0.987 14.6 0.8

20 0.999 19.7 0.4

25 1.005 24.8 0.2

30 1.007 29.9 0.1

35 1.008 35.0 0.1

40 1.009 40.1 0

50 1.008 50.3 0

60 1.007 60.3 0

70 1.006 70.3 0

80 1.005 80.3 0

90 1.004 90.3 0

100 1.003 100.3 0

Run 9, 203 mV

Run 10, 20.1 mV

CF V

p = correction factor peak voltage

OBS At = observed pulse duration

f Correcting the impulse response for transient digitizer calibration

yielded identical values of CF V

p

and OBS At.

19
TABLE 6. Percent deviation of average CF V

p

* from CF V

p

runs (see Fig. 6)

data of individual

APD 723 - 0 dB - No Filter

Input

Gaussian

pulse

duration

ns

Average

CF V/t

of runs

16 & 17

Average

OBS At* *

f of runs

16 & 17

Percent

deviation of

average CF V

p

* from CF Vp of runs 16 6c 17

Impulse

peak vo

response

ltage

10 0.964 9.74 ± 3.2

15 0.982 14.6 2.3

20 0.994 19.7 1.7

25 0.999 24.7 1.4

30 1.002 29.8 1.2

35 1.004 34.9 1.0

40 1.005 40.0 0.9

50 1.005 50.1 0.7

60 1.004 60.2 0.6

70 1.004 70.2 0.4

80 1.003 80.2 0.4

90 1.002 90.2 0.3

100 1.002 100.2 0.2

Run 16, 20 . 9 mV

Run 17, 206 mV

CF V

p = correction factor peak voltage

OBS At = observed pulse duration

f Correcting the impulse response for transient digitizer calibration

yielded identical values of CF V

p and OBS At.

20
TABLE 7. Percent deviation of average CF V

p

* from GF V

p

data of individual

runs ( see Fig. 10)

APD 725 - 0 dB - No Filter

Input

Gaussian

pulse

duration

ns

Average

CF V/t

of runs

1 & 4

Average

OBS At* * f

of runs

1 & 4

Percent

deviation of

average CF V

p

* from CF V

p of runs 1 & 4

Impulse response

peak voltage

10 0.962 9.72 ± 2.2

15 0.980 14.7 1.5

20 0.990 19.7 1.2

25 0.995 24.8 0.9

30 0.998 29.8 0.8

35 0.999 34.9 0.7

40 1.000 39.9 0.7

50 1.001 50.0 0.5

60 1.001 60.0 0.4

70 1.001 70.0 0.3

80 1.001 80.1 0.3

90 1.001 90.1 0.2

100 1.001 100.1 0.2

Run 1 , 204 mV

Run 4 , 19.7 mV

CF V

p = correction factor peak voltage

OBS At = observed pulse duration

f Correcting the impulse response for transient digitizer calibration

yielded identical values of CF V

p

and OBS At.

21
TABLE 8. CF V

p

* as a function of observed pulse duration (OBS At) and input

pulse shape (Table derived from interpolation of graphed data)

APD 721 - 0 dB - No Filter - Run 10

Observed

pulse

duration

(OBS At)

CF V

p Gaussian

input

pulse

CF V

p

Skewed* * Gaussian

input pulse

CF V

p

* Cosinesquared

input pulse

CF V

p Triangular

input pulse

10 0.949 0.932 0.948 1.042

15 0.981 0.963 0.980 1.032

20 0.996 0.985 0.997 1.028

25 1.004 0.997 1.004 1.027

30 1.006 1.003 1.007 1.024

35 1.008 1.006 1.01 1.023

40 1.01 1.008 1.012 1.02

50 1.01 1.01 1.01 1.017

TABLE 9. CF V

p

* as a function of observed pulse duration (OBS At) and input

pulse shape (Table derived from interpolation of graphed data)

APD 721 - 20 dB - No Filter - Run 11

Observed

pulse

duration

(OBS At)

CF V

p

* Gaussian

input

pulse

CF V

p

* Skewed* * Gaussian

input pulse

CF V

p

* Cosinesquared

input pulse

CF V

p

Triangular

input pulse

10 0.921 0.914 0.921 1 .022

15 0.958 0.943 0.962 1 .006

20 0.973 0.963 0.972 1 .010

25 0.982 0.975 0.986 1 .007

30 0.988 0.982 0.989 1 .006

35 0.992 0.987 0.994 1 ,.006

40 0.994 0.990 0.994 1 .005

50 0.996 0.994 0.997 1 .004

CF Vp = correction factor peak voltage

Skewed Gaussian pulses had a Gaussian right side with a FWHM 40%

longer than a Gaussian left side.

22
TABLE 10. CF V

p

* as a function of observed pulse duration (OBS At) and input

pulse shape (Table derived from interpolation of graphed data)

APD 721 - 20 dB - Filter - Run 12

Observed

pulse

duration

(OBS At)

CF Vp*

Gaussian

input

pulse

CF V

p

* Skewed* * Gaussian

input pulse

CF V

p

* Cosinesquared

input pulse

CF V

p

* Triangular

input pulse

16 1.418 1.427 1.373 1.524

20 1.178 1.193 1.147 1.279

25 1.091 1.090 1.067 1.182

30 1.055 1.051 1.039 1.143

35 1.033 1.033 1.029 1.122

40 1.022 1.023 1.022 1.103

50 1.008 1.010 1.008 1.070

TABLE 11. CF V

p

* as a function of observed pulse duration (OBS At) and input

pulse shape (Table derived from interpolation of graphed data)

Observed

pulse

duration

(OBS At)

APD 721 - 40 dB - Filter - Run 13

CF V

p

* Gaussian

input

pulse

CF V

p

* Skewed* * Gaussian

input pulse

CF V

p

* Cosinesquared

input pulse

CF V

p

* Triangular

input pulse

16 1.462 - 1.428 1.550

20 1.153 1.170 1.121 1.248

25 1.050 1.050 1.032 1.149

30 1.019 1.014 1.004 1.108

35 1.003 0.998 0.994 1.087

40 0.995 0.992 0.992 1.073

50 0.987 0.985 0.986 1.052

CF Vp = correction factor peak voltage

Skewed Gaussian pulses had a Gaussian right side with a FWHM 40%

longer than a Gaussian left side.

23
TEMP.

CONTROLLER TEMP

PS METER

Figure 1. APD Transfer Standard System

j

: 24
1.60

25

Figure

2.

APD

721- 0

dBNo

Filter.

(Average

of

runs 9

and

10).

Average

values

of

peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

in

ns

for

impulse

response

maximum

of

203

mV

and

20.1

mV.
1.60 o

LO o o

00 oCsJ oo o

O') o

0)

CO 1—

p • P-I >E

XI

CD LO > a>

5-i r-H

Cl) CO 4-4 -p 0 0 6

CO P p 6

CO •H

5-i CD

p > E

CD Pp CO

r-H o G

r-H

O

aa c > CO n—

CD

p^; at

U i o CD

4-J CO

M

O i—

0) P P U 4-1 04 i—

E

•H

C •H

Pp o

•H

u

O 4-1 o a 44

CD 1 uu 4-1 PQ o <1 x a

CO o CD PP

CnI bO o p s—

1 4-1 1—

G

r-H o O

CN > •H

4-i P O p U

P-i CD P

<q pp

X

oo0) uP

bO

•H

JO

d

A

26
1.60

COc

GO

OQO

J0

d

A

27

Figure

4.

APD

721-

20

dBFilter -

Run

12

Peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

for

impulse

response

maximum

of

52.7

mV.
1.60

dO d A

28

Figure

5.

APD

721

-

40

dB

-

Filter

-

Run

13

Peak

volatage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

for

impulse

response

maximum

of

147

mV.
1.60

29

Figure

6.

APD

723- 0

dBNo

Filter.

(Average

of

runs

16

and

17).

Average

values

of

peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

in

ns

for

impulse

response

maximum

of

209

mV

and

20.6

mV.
1.60 o

LO

o*3

" o

00

o

CM

o o

CD

JO d A

30

Figure

7

.

APD

723

-

20

dB

-

No

Filter

-

Run

19

Peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(0BS

At)

for

impulse

response

maximum

of

199

mV.
1.60

Figure

8.

APD

723-

20

dBFilter -

Run

20

Peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

for

impulse

response

maximum

of

59.9

mV.
1.60

32

Figure

9.

APD

723-

40

dBFilter -

Run

21

Peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

for

impulse

response

maximum

of

248

mV.
1.60

33

Figure

10.

APD

725- 0

dBNo

Filter.

(Average

of

runs 1

and

4).

Average

values

of

peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

in

ns

for

impulse

response

maximum

of

204

mV

and

19.7

mV.
1.60

34

Figure

11.

APD

725-

20

dBNo

Filter -

Run 6

Peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

for

impulse

response

maximum

of

197

mV.
1.60

35

Figure

12.

APD

725-

20

dBFilter -

Run

15

Peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

for

impulse

response

maximum

of

51.1

mV.
1.60

36

Figure

13.

APD

725-

40

dBFilter -

Run

14

Peak

voltage

correction

factor

(Vp

CF)

versus

observed

pulse

duration

(OBS

At)

for

impulse

response

maximum

of

238

mV.
NBS-1 14A (REV. 2-80

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

4. TITLE AND SU BTITLE

1. PUBLICATION OR

REPORT NO.

2. Performing Organ. Report No. 3. Publication Date

NISTIR 89-3917 August 1989

Improved Low-Level Silicon-Avalanche-Photodiode Transfer Standards at

1.064 Micrometers.

5. AUTHOR(S)

A.L. Rasmussen, P.A. Simpson, and A. A. Sanders

6. PERFORMING ORGANIZATION (If joint or other than NBS, see in struction s) National Institute of Standards and Technology

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

9.

SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City, State, ZIP)

7. Contract/Grant No.

8. Type of Report & Period Covered

Aerospace Guidance and Metrology Center

Newark Air Force Station, Ohio

10.

SUPPLEMENTARY NOTES

H Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11.

ABSTRACT (A 200-word or less factual summary of most si gnifi cant information . I f document includes a significant

bi bl iography or literature survey, mention it here)

Three silicon-avalanche-photodiode (APD) transfer standards were calibrated from ~10 3 to ~10~ 5 W/cm2 peak power density at approximately 10% uncertainty. These calibrations

are for 1.064 /im wavelength pulses of 10 to 100 ns duration. For this calibration, an

acousto-optically modulated laser beam generated alternately equal levels of pulsed

power and cw power into a low-level beam splitter. The cw power measured by a transfer

standard in the transmitted beam of the splitter was used to determine the pulsed power

into the APD transfer standard in one of the low-level reflected beams of the splitter.

The APD detector had about a 1 cm2 aperture and a 3.8 cm focal length lens in front of

it. Lens, window, and detector surfaces had narrow-band antireflection coatings. The

commercial detector package is a temperature compensated, infrared-enhanced APD

preamplifier module. To increase the sensitivity, one or two 20 dB , 500 MHz bandwidth

amplifiers followed the preamplifier. With very low pulsed power, a 30 MHz low-pass

filter with Gaussian roll-off was attached to the amplifier output to reduce the noise.

A transient digitizer recorded the impulse responses of the APD detectors at 1.064 /um.

These data were read into computer programs that convolved the unit-area impulse

response with unit-height Gaussian pulses. From these data, correction factors of the

pulse peak for observed pulse durations from 10 to 100 ns were determined.

Instructions, calibrations, error budgets, and system descriptions are included.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

detector impulse response; laser detectors; laser pulse standards; lowlevel pulse detectors; pulse power measurements; YAG laser pulse calibrations

13. AVAILABILITY 14. NO. OF

PRINTED PAGES

jXl Unl i mi ted

kJ For Official Distribution. Do Not Release to NTIS 44

~k| Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402. 15. Price

[X] Order From National Technical Information Service (NTIS), Springfield, VA. 22161

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