Manual 19-11-11

Microwave & Optical Communication Lab

Exp. No. :

Date :

MODE CHARACTERISTICS OF REFLEX KLYSTRON

AIM:

To study the mode characteristics of reflex klystron.

EQUIPMENTS:

1. Klystron power supply

2. Reflex Klystron with mount

3. Isolator

4. Variable Attenuator

5. Frequency meter

6. Waveguide-detector mount with detector

7. Micro ammeter, VSWR meter

8. Wave guide stand and accessories.

PROCEDURE:

a) Carrier Wave operation

1. Assemble the equipment as shown in figure with microammeter as indicating meter

2. Fire the Klystron correctly for CW operation with optimum beam voltage

3. Adjust the repeller voltage to maximum negative value and decrease it in steps of 1V and record o/p

power and frequency in table. The frequency is measured by tuning the frequency meter to have a dip in

the o/p each time. The frequency meter should be detuned each time while measuring power

4. Plot power/frequency versus repeller voltage to get mode curves-figure

5. Compute various parameters from the graph

Dept. Of Electronics & Communication 1


b) Modulated source (square wave operation)

1. Assemble the equipment as shown in figure with VSWR meter as indicating meter

2. Set the mod-selector switch to AM-MOD position. Keep AM-MOD and AM- FRE, knob at the mid

position

3. Fire the Klystron correctly for square wave operation with optimum beam voltage

4. Adjust the modulation voltage and repeller voltage to obtain maximum reading in the VSWR meter and

read it on the power scale

5. Also adjust the klystron tuning plunger for a maximum in VSWR meter.

6. Repeat steps 3 to 6 of CW procedure

RESULT:



Figure: Mode Characteristics of reflex klystron

K Kly

Figure: Setup for study of Klystron tube


Klystron Power Supply

Klystron Mount + Tube

Frequency meter

Variable attenuator

Isolator Detector mount

Micro ammeter

VSWR Meter


Table: Mode Characteristics of Reflex Klystron

Sl no Repeller voltage,( V) Microammeter reading ( μ A ) Frequency,( GHz)



Exp. No. :

Date :

GUNN DIODE CHARACTERISTICS

AIM:

To study the Gunn oscillator as a source of microwave power and hence to study the

a) I-V characteristics

b) To find the threshold voltage.

EQUIPMENTS:

1 Gunn Oscillator

2 Gunn Oscillator power supply

3 PIN diode modulator

4 Isolator

5 Frequency meter

6 Attenuator

7 Detector with tunable mount.

PROCEDURE:

1. Set the equipment as shown in figure.

2. Set the Gunn oscillator micrometer tuning screw at suitable frequency (~9GHz). Adjust attenuator for

suitable power level

3. Change Gunn biasing in steps of 0.5V and record corresponding currents in the table (read current in the

panel meter of the Gunn power supply)

4. Draw the current voltage characteristic.

5. Set the Gunn bias voltage above Vo and with zero attenuation. Record power and frequency for this

Gunn diode biasing

6. Reduce the Gunn biasing in steps of 0.5V and record corresponding power and frequency

7. Plot power/frequency versus bias characteristics



8. With Gunn oscillator micrometer screw in the middle of its range, set Gunn biasing for maximum power

o/p and record in table this power and frequency of oscillation

9. Move micrometer screw to one extreme till power falls to a low but readable value

10. Move micrometer screw in the opposite direction in steps of 0.5mm and record in table, the power and

corresponding frequency till the screw reaches another extreme

11. Plot power versus frequency characteristics and frequency versus micrometer reading curve-the

calibration curve

RESULT:



Figure: I-V Characteristics of Gunn oscillator

K Kly

Figure: Setup for the study of Gunn Diode


Vo V--

<----I

Power Supply

Gunn Oscillator

AttenuatorFr. Meter

PIN Modulator

Isolator

Micro Ammeter

Detector mount

V I


Micrometer Reading = Frequency =

Table: I-V Characteristics

Sl no Bias Voltage (V) Current (mA) Threshold Voltage (V)



Exp. No. :

Date :

FREQUENCY AND WAVELENGTH MEASUREMENT

AIM:

To determine the frequency and wavelength in a rectangular waveguide and to verify the relation between λ0 ,

λg, and λc

EQUIPMENTS :

1. Klystron oscillaltor,

2. Isolator,

3. Frequency meter,

4. Variable attenuator,

5. Standing wave detector,

6. Movable short terminator

7. Klystron power supply

8. VSWR meter

PROCEDURE:

Frequency measurement:

1. Set up the microwave bench as shown in figure

2. Set variable attenuator at minimum position

3. Set VSWR meter at 40dB

4. Switch ON klystron power supply. Modulate with 1kHz square wave

5. Adjust the reflector voltage to get maximum deflection in the VSWR meter.

6. Maximize the deflection with tuning probe in the VSWR meter

7. Frequency measurement using frequency meter

8. Tune the frequency meter until a dip is observed in the VSWR meter. Also tune the frequency meter to

obtain minimum deflection. Note frequency directly from frequency meter.



Wavelength measurement:

9. Replace the termination with variable short. Detune the frequency meter.

10. Move the probe along slotted line. The deflection in the VSWR meter will vary.

11. Move probe to minimum deflection point.

12. Move the probe to next minimum position and record the probe position. Calculate guide wavelength as

twice the distance

13. Calculate guide wavelength (λg) as twice the distance between minimum positions.

14. λc is calculated as 2a, where a is the inner dimension of waveguide broader side

15. Calculate λO as

16. Calculate frequency using the expression f0= c/ λ0

RESULT



K Kly

Figure: Setup for frequency & wavelength measurements




Frequency meter

Variable attenuator

Isolator Slotted Line

Termination

VSWR Meter


Exp. No. :

Date :

ATTENUATOR CHARACTERISTICS

AIM:

To study the attenuator characteristics by

a) Measuring the insertion loss and

b) Plotting o/p power versus micrometer reading for the given variable attenuator.

EQUIPMENTS:

Standard microwave test bench and the given test attenuator.

PROCEDURE:

1. Assemble the equipment as shown in figure with VSWR as indicating meter

2. Fire the Klystron correctly for AM-MOD operation with optimum beam voltage

3. Adjust for maximum power o/p (~30dB). Note the o/p power in VSWR meter (P0)

4. Insert the test attenuator between frequency meter and detector mount without disturbing the bench.

5. Move the micrometer screw to fully released position. Note the o/p power in VSWR meter (P1).

Calculate the insertion loss as (P0-P1)

6. Move the micrometer screw in the opposite direction in steps of 0.5mm and note down the

corresponding power (P2) from the VSWR meter

7. Find out the attenuation (P1-P2) value for different micrometer readings and plot the graph



K Kly

Figure: Setup for studying attenuator characteristics

Table: Attenuator Characteristics

Input power P0 =

Sl no Micrometer reading (mm) o/p Power (dB) P2 P0-P2 (dB)




Frequency meter

IsolatorAttenuator

TestAttenuator

Detector mount

VSWR Meter


Calculation:

Frequency of operation =

Output power P1 =

Insertion loss = P0-P1 =

RESULT:



Exp. No. :

Date :

DIRECTIONAL COUPLER

AIM:

To measure the coupling factor, insertion loss and directivity

EQUIPMENTS:

Standard microwave test bench and the directional coupler under test and matched load.

PROCEDURE:



3. Adjust for maximum power o/p (~30dB). Note the o/p power in VSWR meter (Pi)

4. Insert the test directional coupler in the forward direction between frequency meter and detector

mount without disturbing the bench and connect the detector to the auxiliary arm with the main arm

o/p terminated in matched load

5. Note the auxiliary arm o/p power in VSWR meter (Pao), ie., the power coupled to the auxiliary arm.

Also calculate the coupling factor (C) as Pi-Pao.

6. Now carefully interchange the detector of the auxiliary line o/p and matched load of the main line

without disturbing the setup.

7. Note the main arm o/p power in VSWR meter (Po), and calculate insertion loss (L) as Pi-Po

8. Restore the original arrangement, with the exception that the directional coupler under test be in the

reverse direction.

9. Note the auxiliary arm o/p power in VSWR meter (Pd), it is assumed that Pi is same as before. The

directivity (D) is calculated as Pao-Pd

10. Compute the isolation (I) as Pi-Pd and also check I=C+D

RESULT



Figure: Directional coupler

K Kly

Figure: Setup for studying isolator & circulator

Calculation:


Table: Directional coupler

Sl no Pi (db)Pao

(db)Po (db) Pd (db) C (dB) L (dB) D (dB)

I =

C+D

(dB)

1

2


I/p, Port 1

O/pPort 2

Port 4

Port 3



Isolator+Attenuator+Fr. Meter

Directional Aux armMain armCoupler

Detector mount

VSWR Meter

Matchedload


Exp. No. :

Date :

E-PLANE TEE & H-PLANE TEE

AIM:

To study the properties of E- and H-plane tee junctions and to determine isolations and coupling coefficients.

EQUIPMENTS:

Standard microwave test bench and the E- and H-plane tee junctions under test and matched load

PROCEDURE:



3. Adjust for maximum power o/p (~30dB). Note the o/p power in VSWR meter (Pi)

4. Insert the test E-plane tee junction between frequency meter and detector mount without disturbing the

bench. and connect the detector to one of the ports and terminate the other in a matched load.

5. Determine the isolation in decibels by noting the o/p level in the VSWR meter (db scale)

6. Interchange the position of the detector and matched load and determine the isolation in decibels by

noting the change in the o/p level

7. Repeat steps 4, 5 and 6 for other orientations of the tee as well as for H-plane tee also.

8. Calculate the coupling coefficient from C=10 (-α/20), where α is the attenuation. Substitute the isolation

calculated in each case as α and hence calculate coupling coefficient.

RESULT:




1

2

3

H-Plane Tee

1

E-Plane Tee

2

3


K Kly

Figure: Setup for studying E, H-plane

Calculation:


Table: Insertion loss

i/p portPower at i/p

(dB)o/p port

Power at o/p

(dB)

Insertion

loss (dB)

Port 1 Port 2 I12 =

Port 3 I13 =

Port 2Port 1 I21 =

Port 3 I23 =

Port 3Port 1 I31 =

Port 2 I32 =

α1 = (I12+I21)/2 = α2 = (I23+I32)/2 = α3 = (I13+I31)/2

Hence the corresponding coupling factors are

C1 = C2 = C3 =





E-, H-planeTee

Detector mount

VSWR Meter

Matchedload


Exp. No. :

Date :

LOW VSWR MEASUREMENT

AIM:

To study the method of measuring VSWR at the input of the component under test or unknown load when

VSWR < 10

EQUIPMENTS:

1. Standard microwave test bench

2. Slotted section slide screw tuner

3. Components under test.

PROCEDURE:

1. Assemble the equipment as shown in figure with microammeter as indicating meter

2. Terminate the load end with the given slide screw tuner followed by the matched load.


4. Tune the detector by adjusting the stub length for maximum meter deflection. Also set the slide screw

tuner for the desired VSWR

5. Set the probe position for maximum reading on microammeter. That is at voltage maximum of the

standing wave. Record the meter reading in the table

6. Move the probe along the slotted line and adjust it at minimum position, read and record in table.

7. Calculate the VSWR as (Imax/Imin)1/2.

8. Repeat the same for different components.

a. If a VSWR meter is used in place of microammeter, set the klystron for square wave modulation

and follow the following steps

9. Adjust the gain of the VSWR meter amplifier to give full scale deflection to read 1.00 on the VSWR

meter at the voltage maximum (step 5)

10. Move the probe along the slotted line and adjust it at minimum position, note the VSWR meter reading.

This gives the VSWR directly when the maximum is set for 1.00



Note 1: A slide screw tuner can be used between the slotted section and the component for generating any

desired VSWR between 1 and 10.

Note 2: A matched load has a VSWR close to unity. Hence to measure the VSWR of this matched load, the

slide screw tuner setup should be removed and only the matched load is connected. Then the measurement

procedure is same as before, but since the VSWR is close to unity, VSWR reading is taken after the VSWR

meter scale is set in the 1 to ∞ range. If the reading is less than 1.3, then it is changed over to EXPANDED

SWR scale when the slotted line probe is in the field minimum position. This reading gives the VSWR of the

matched load which will be close to unity ( do the experiment for

1) open ended wave guide 2) a blank flange 3) a terminated fixed attenuator

Note 3: Unloaded Q of a Cavity resonator. Connect the given test cavity in place of slide screw tuner and

matched load. Measure the VSWR for different frequencies and compute the Q of the cavity as explained in

appendix.

RESULT:



Standing wave patterns

K Kly

Figure: Setup for studying VSWR




Isolator+Attenuator+ Fr. Meter

Slotted section

Slide MatchedScrew LoadTuner

VSWR MeterDetector Mount


Calculation:

Table: Low VSWR measurement

Sl noMaximum reading

[I max (μA)]

Minimum reading

[I min (μA)] S=

[ In VSWR meter set the maximum reading as 1, hence minimum reading directly gives the VSWR]

Table: Low VSWR measurement ( VSWR meter)

Sl no S=



Exp. No. :

Date :

IMPEDANCE MEASUREMENT

AIM:

To measure the unknown impedance of the given device

EQUIPMENTS:

Standard microwave test bench, slotted section, iris backed with a matched load (a flat plate with round hole) as

unknown impedance and blank flange.

PROCEDURE:

1. Assemble the equipment as shown in figure with VSWR meter as indicating meter


3. Adjust for maximum power o/p (~30dB).

4. Terminate the slotted section with the blank flange and accurately measure the position of the voltage

minima (S1). (See figure) .Also calculate guide wave length.

5. Connect the device under test in place of blank flange and measure VSWR and the new positions of the

minima (X1). The VSWR can be used to calculate magnitude and the shift in position of the minima for

calculating the phase of the reflection coefficient. Note down lmin = S1-X1. Also determine the VSWR

value S and λg.

6. Compute the unknown load impedance of the given device from the lmin, S and λg analytically as

ZL=Zo (1-jStanβlmin)/ (S-jtanβlmin) or by using smith chart.

RESULT:



K Kly

Figure: Setup for Impedance measurement





Slotted section

Iris Matched Load

VSWR MeterDetector Mount


Calculation:

Table: Impedace measurement

Sl. no S1 (cm) S2 (cm) X1(cm) λg (cm) lmin (cm)

Guide wave length =

VSWR, S =

Zmin =

β = 2π/λg =

ZL=Zo (1-jStanβlmin)/ (S-jtanβlmin) =



Exp. No. :

Date :

DIELECTRIC CONSTANT MEASUREMENT

AIM:

To study the two-point method for measuring dielectric constant of the given low loss solid dielectric (Teflon)

EQUIPMENTS:

Standard microwave test bench and slotted section samples of given dielectric and blank flange.

PROCEDURE

1. Assemble the equipment as shown in figure with microammeter as indicating meter. Terminate the load

end with the short circuit.


3. Tune the detector by adjusting the stub length for maximum meter deflection.

4. With no sample in the shorted wave guide, measure and record in the table the positions of standing

wave minima, starting from any arbitrary plane d =0 as shown in figure.Compute guide wavelength.

The position of the first minima is taken as d1min

5. Using frequency meter determine the frequency of operation and compute the free space wavelength

(verify the value by using λg and λc=2a)

6. Remove the short circuit, insert gently the dielectric sample and replace the short- circuit in such a

manner that it touches the end of the sample

7. Measure and record in table the position of the standing wave voltage minima from the same

reference plane as chosen in step 5. The position of the first minima (with dielectric is taken as d2min)

8. Find out the VSWR.

9. Measure and record waveguide dimensions. (For necessary theory refer appendix)

10. Calculate the dielectric constant (detailed description of the calculations are shown in appendix)

RESULT:



Figure: Setup for measuring the dielectric constant

Calculations:

Waveguide dimension , a= b=

Cut of wavelength λc (=2a) =


Guide wave length λg (without dielectric) =

Guide wavelength λd (with dielectric) =

Table: Dielectric constant

Sl

noSample

Thickness

t1 (cm)

d 1min

(cm)

d2min

(cm)

tan β(δ1+t1))/

(β t1)

tan (βdt1)/

(βd t1)

Possible

values of X

X1 =

X2 =

X3=

X1 =

X2 =

X3=

X1 =

X2 =

X3=




Isolator+Attenuator

Fr. Meter

Slotted section with

dielectric

Short circuit

MicroammeterDetector Mount


Exp. No. :

Date :

HORN ANTENNA

AIM:

To study the E-plane and H-plane radiation pattern of a pyramidal horn antenna and compute

a) Beam width

b) Directional gain of the antenna.

EQUIPMENTS:

Standard microwave test bench, horn antennae, waveguide twist etc.

.

PROCEDURE:

1. Assemble the equipment as shown in figure with horns properly aligned and distance between antennas

equal to double of rmin > 2D2/λo . E vector must be parallel to the ground

2. Fire the Klystron correctly for CW operation with optimum beam voltage micrometer as indicating

meter

3. Adjust for maximum power o/p (~30dB). Record this power received in the table

4. Rotate the receiving antenna in steps of 10deg. On both the sides and enter it in the table

5. Plot the E plane radiation pattern and determine the half power beam width ӨE. compare it with the

theoretical value (ӨE.=53λo/b)

6. Repeat the procedure after replacing the waveguide twists with a straight wave guide and compute ӨH

(ӨH.=80λo/a)

7. Compute the directional gain of the antenna using G= 13326/ ӨE ӨH

8. Compare it with the theoretical value of G=2πab/ λo2



Figure: Setup for studying Horn antenna

Figure: Antenna radiation pattern, rectangular plot


30 20 0 20 30 Angular displacement

0db

-3db


Table: Antenna field pattern

Sl no E-plane setting H-plane setting

Angular

setting (deg)

o/p current (μA) Angular

setting

o/p current (μA)

Left right Left right

1 5 5

2 10 10

3 15 15

4 20 20

5 25 25

6 30 30

7 35 35

8 40 40

9 45 45

10 50 50

11 55 55

12 60 60

13 65 65

14 70 70

15 75 75

16 80 80

17 85 85

18 90 90

Calculations:

Waveguide dimension, a = b =


Free space wavelength =

ӨE.=53λo/b =

ӨH.=80λo/a =

G= 13326/ ӨE ӨH =

G=2πab/ λo2 =



RESULT:



OPTICAL EXPERIMENTS



Exp. No. :

Date :

STUDY OF LOSSES IN OPTICAL FIBER

AIM:

To measure propagation loss and bending loss for two plastic fibers.

EQUIPMENTS:

1. Link-B kit with power supply,

2. Patch chords,

3. 20MHz dual channel oscilloscope,

4. 1MHz function generator,

5. 1&3m fiber cable.

PROCEDURE:

1. Make the connections. Connect the power supply cables with proper polarities to link-B kit. While

connecting this ensures that the power supply is OFF.

2. Keep the SW9 towards TX1 position for SFH756

3. Keep jumpers and SW8 positions as shown in fig.

4. Keep intensity control pot P2 towards minimum position.

5. Switch ON power supply.

6. Feed about 2Vp-p sinusoidal signal of 1 kHz from the function generator to the IN post of analog buffer.

7. Connect the output post OUT of analog buffer to the post TX IN of transmitter.

8. Slightly unscrew the cap of SFH756 V (660nm).Do not remove the cap from the connector. Once the cap

is loosened, insert the 1m fiber in to the cap. Now tighten the cap by unscrewing it back

9. Connect the other end of the fiber to the detector SFH350V (phototransistor detector) very carefully as per

the instructions above.



10. Observe the detected signal at post ANALOG OUT on oscilloscope. Adjust intensity control pot P2

optical power control potentiometer so that you receive signal of 2V p-p.

11. Measure the peak value of received signal at ANALOG OUT terminal. Let this value be V1.

12. Now replace 1m fiber with 3m fiber between same Led and detector. Do not disturb any settings. Again

take peak voltage reading and let it be V2.

13. If α is the attenuation of the fiber then we have P1/P2 =V1/V2= e[-α(L1+L2)] where

Where α = nepers/meter,

L1= Fiber length for V1

L2 = Fiber length for V2

This α is for peak wave length of 660nm

14. Switch OFF the power supply.

15. Keep SW9 towards TX1 position for SFH 756.

16. Set the jumpers to form simple analog link using LED SFH 450 V at 950nm and phototransistor SFH

350V with 1m fiber cable.

17. Switch ON power supply.

18. Repeat the same procedure as above for this link to get α at 950 nm and compare the α values.

MEASUREMENT OF BENDING LOSS:

1. Set up the 660 nm analog link using 1m fiber as per the above procedure.

2. Bend the fiber in a loop and measure the amplitude of received signal.

3. Keep reducing the diameter of bend to about 2 cm and take corresponding out voltage

readings (do not reduce loop diameter less than 1cm).

4. Plot the graph of received signal amplitude versus loop diameter repeat the procedure for second transmitter.



Figure : Jumper diagram for the study of losses

RESULT:



Exp. No. :

Date :

STUDY OF NUMERICAL APERTURE OF OPTICAL FIBER

AIM:

To measure the numerical aperture of optical fiber provided with the kit using 650nm wavelength LED and

find the V –number.

EQUIPMENTS:

1. FCL-01,

2. 1m fiber cable,

3. Ruler,

4. Power supply,

5. NA JIG.

PROCEDURE:

1. Make connections as shown in fig. Connect the power supply cables with proper polarity to FCL -01 kit.

While connecting this, ensure that power supply is OFF.

2. Slightly unscrew the cap of LED SFH 756V (660 nm).Do not remove the cap from the connector. Once

the cap is loosened, insert the fiber in to the cap. Now tighten the cap by screwing it back.

3. Keep the jumpers JP1, JP2 and JP4 on FCL 01 as shown in figure.

4. Keep the switch S2 in VI position.

5. Switch ON the power supply.

6. Insert the other end of the fiber in to the numerical aperture measurement JIG. Hold the white sheet facing

the fiber. Adjust the fiber such that its cut face is perpendicular to the axis of fiber.

7. Keep the distance of about 10mm between fiber tip and screen. Gently tighten the screw and thus fix the

fiber in the place.

8. Observe the bright red spot on the screen by varying intensity pot P3 and bias pot P4.

9. Measure exactly the distance d and also the vertical and horizontal diameters MR and PN as indicated in

the figure



10. Mean radius is calculate using the formulae r = (MR+PN)/4

11. Find the numerical aperture of the fiber using the formulae

NA= sinθmax = r / d2+r2 where θmax is the maximum angle at which light

incident is properly transmitted through the fiber.

12. V- number can be calculated using the formulae:

V=2Π* NA *a / Λ

where a is the core radius of the fiber, NA is the Numerical aperture, Λ is the wavelength .



Figure : Jumper diagram for measurement of numerical aperture



RESULT:



Exp. No. :

Date :

STUDY OF CHARACTERISTICS OF FIBER OPTIC LED AND PHOTODETECTOR:

AIM:

To study the VI characteristics of fiber optic LED and plot the graph of forward current versus output

optical energy and also to study the photo detector response.

EQUIPMENTS:

FCL-01 & FCL-02, 1meter Fiber cable, Patch chords, Jumper to crocodile wires, Power Supply, Voltmeter,

Current meter, 20 MHz Dual Channel Oscilloscope.

PROCEDURE:

1. Make connections as shown in figure. Connect the power supply with proper polarity to FCL-01 & FCL-

02 Kits. While connecting this, ensure that the power supply is off.

2. Slightly unscrew the cap of LED SFH 756V (660 nm) .Don’t remove the cap from the connector. Once

the cap is loosened, insert the 1meter fiber into the cap. Now tighten the cap by screwing it back.

3. Slightly unscrew the cap of Photo detector SFH 250V. Don’t remove the cap from the connector. Once the

cap is loosened, insert the other end of the fiber into the cap. Now tighten the cap by screwing it back.

4. Keep the jumpers JP1, JP2, JP3 & JP4 on FCL-01 as shown in figure.

5. Keep jumpers JP1 &JP2 on FCL-02 as shown in figure.

6. Keep switch S2 in VI position on FCL-01

7. Connect voltmeter and current meter as per the polarities shown in figure.

8. Switch on the power supply.

9. Keep the potentiometer P3 in its maximum position.P3 is used to control current flowing through LED.

10. Keep potentiometer P4 in its fully clockwise rotation.P4 is used to control bias voltage of LED.

11. To get the VI characteristics of LED, rotate P3 slowly and measure the forward current and

corresponding forward voltage.



12. For each reading taken above, find out power, which is the product of I and V. This is the electrical power

supplied to the LED. Data sheets for the Led specify optical power coupled into plastic fiber when

forward current was 10 mA as 200 µW. This means that the electrical power at 10 mA current is

converted into 200 µW of optical energy. Hence the efficiency of LED comes out to be approximately

1.15%.

13. With this efficiency assumed, find out optical power coupled into plastic optical fiber for each of the

reading. Plot the graph of forward current versus output optical power of the LED.

14. Similarly measure the current at the detector.

15. Plot the graph of receiver current versus output optical power of the LED.

16. Perform the above procedure again for all the combinations of the Transmitter & Receiver





RESULT:



OBSERVATION & CALCULATION

Vf= Forward voltage of LED SFH 756

If=Forward Current of LED SHF 756

Pi =V* I (Electrical Power)

Po=Pi* 1.15 % (Optical power of LED 756)

V=Output Voltage of SFH 250

I=Output Current of SFH 250

VI CHARACTERISTICS OF FIBER OPTIC LED & DETECTOR


Vf(V) If (mA) Pi(mW) Po(µW) V (V) I (µA)

Manual 19-11-11

Documents

plane setting

square wave

move micrometer

optical power

optical communication

1m fiber cable

power supply

led sfh 756v