PART1 STUDY OF FUSION SPLICING MACHINE AND FACTOR

AFFECTING SPLICING LOSS

1. INTRODUCTION The capacity of optical fibers to carry high bandwidth signals over longer distances without significant attenuation has been an important asset for global communications network. The basic need of joining several of optical components is simply to gain larger distances which can be met only through fiber joints. In many applications of optical fiber it is necessary to connect fiber ends in some way such that light from one fiber can get into the other fiber without losing too much of its optical power. So it is very important to study method and technique so that we can make a fiber joint, which allow very little loss of power . In fusion splicing machine there are many parameter by which we can study that what are the major parameter which effect the splice loss most e.g. offset , arc time ,act power etc. although splicing machine show loss on the screen but we use cut back method to find the actual loss . it is found the loss by cutback method is greater as in case of splicing machine reading.

2. TYPES OF JOINTS IN FIBER:

1. FIBER OPTIC CONNECTOR : These are removable joints which allow easy, fast, manual coupling and uncoupling of fibers. The connectors mechanically couple and align the cores of fibers so that light can pass. Better connectors lose very little light due to reflection or misalignment of the fibers .typical loss due to connector is 0.5 dB.

2. MACHNICAL SPLICE : Fiber optic mechanical splice performs a similar function to the fusion splice except that the fibers are held together by mechanical means rather than by a welding technique. Mechanical splices somewhat look like fusion splice protection sleeves. In a mechanical splice, two cleaved fiber tips are mechanically aligned to each other by a special housing. Usually, index matching gel is positioned between the fiber tips to maximize coupling and minimize back reflection.There are some significant advantages of using mechanical fiber splice than fusion splices. Here are a few of them:

1) Mechanical splices require no power supplies. 2) Many mechanical fiber splice designs require no extra tools beyond a fiber stripper and fiber cleaver 3) They can be used in situations where fusion splicing is not practical or impossible 4) Mechanical splices can be made within a couple of minutes, this makes it ideal for temporary connections.Disadvantages of mechanical splice over fusion splice

1) Higher insertion loss. The typical insertion loss for a mechanical splice is about 0.2dB which is significantly higher than the 0.02dB loss for a typical fusion splice.

2) Mechanical splices are typically for multimode fibers. The tough alignment tolerance for single mode fibers makes it hard for mechanical splices to meet.

3) Since the refractive index of most index matching compounds varies with temperature, so the optical performance of a mechanical splice can be sensitive to ambient temperature

4) Mechanical splices are not thought to be as reliable as fusion splices over long periods of time

3. FUSION SPLICE : These joint are permanent and very low loss joint and hence they are very important in long distance communication. These joint are typical give loss of 0.01 dB .

FUSION SPLICING ADVANTAGE:

Over connectors and mechanical splicing, fusion splicing has many advantages as explained below.

1. Lowest back reflection (optical return loss ORL)2. Lowest insertion loss3. Highest mechanical strength4. Prevents dust and other contaminants from entering the optical path5. Permanent6. Can with stand extreme high temperature changes.

3. WORKING OF FUSION SPLICING MACHINE :

Fusion splicing is done with a specialized instrument that typically operates as follows: The two cable ends are fastened inside a splice enclosure that will protect the splices, and the fiber ends are stripped of their protective outer jacket. The ends are cleaved (cut) with a precision cleaver to make them perpendicular, and are placed into special holders in the splicer. The splice is usually inspected via a magnified viewing screen to check fiber before and after the splice. The splicer uses small motors to align the end faces together, and emits a small spark between electrodes at the gap to burn off dust and moisture. Then the splicer generates a larger spark that raises the temperature above the melting point of the glass, fusing the ends together permanently. The location and energy of the spark is carefully controlled so that the molten core and cladding do not mix, and this minimizes optical loss. A splice loss estimate is measured by the splice machine and it shows on the screen in dB .Typical value of splice loss is 0.02 dB .

Fiber splicing can be done in the following sequence

Fiber stripping , cleaving, fiber alignment , fiber welding , insertion loss estimation, pull tension strength testing, splice protection with fusion splice sleeve.

4 PARAMETER AFFECTING SPLICE LOSS:

Connector and splice loss is caused by a number of factors. Loss is minimized when the two fiber cores are identical and perfectly aligned, the connectors or splices are properly finished and no dirt is present. Only the light that is coupled into the receiving fiber's core will propagate, so all the rest of the light becomes the connector or splice loss. The parameter which control loss in any fiber joining method can be classified as:

Extrinsic parameters:

1. End gap : These involves contamination at the fiber end and lateral and angular alignment gaps. End gaps cause two problems, insertion loss and return loss. The emerging cone of light from the connector will fall over the core of the receiving fiber and be lost. In addition, the air gap between the fibers causes a reflection when the light encounters the change in refractive index from the glass fiber to the air in the gap. This reflection (called fresnel reflection) amounts to about 5% loss in typical flat polished connectors, and means that no connector with an air gap can have less than 0.3 dB loss.

2. Fiber cleave angle: fiber cleave angle is another important extrinsic parameter. Proper fiber end preparation is the most fundamental step to acceptable splice loss. Generally cleave angle less than two degrees gives acceptable splice loss.

Intrinsic parameters:

Intrinsic or fiber related parameters are determined when the fiber is manufactured and cannot be controlled by the individual doing splicing. Mode Field Diameter (MFD) is the most important intrinsic parameter. More splice loss can be observed for higher difference in MFD values. The MFD is a characteristic, which describes the mode field (cross-sectional area of light) traveling down a fiber at a given wavelength. When fibers with different MFD values are spliced together, a MFD mismatch occurs at splice point. Two sources of loss are directional; numerical aperture (NA) and core diameter. Differences in these two will create connections that have different losses depending on the direction of light propagation. Light from a fiber with a larger NA will be more sensitive to angularity and end gap, so transmission from a fiber of larger NA to one of smaller NA will be higher loss than the reverse. Likewise, light from a larger fiber will have high loss coupled to a fiber of smaller diameter, while one can couple a small diameter fiber to a large diameter fiber with minimal loss, since it is much less sensitive to end gap or lateral offset

Prefuse power: It sets a span of time from the start of arc to fiber proceeding as the initial ARC POWER. In this point , if initial ARC POWER value is low, the section angle of the fiber can be bad , resulting in an axial offset. If the value is too high, the fiber can be burning or become round, causing the deterioration of splice loss

Prefuse time: It set a span of time from the start of arc to fiber proceeding as the initial arc time. Long means high power

Arc time is the time during which the fibers are fuse and stuffed into each other. Low arc times lead to incomplete fusion while high arc times lead to burning of the fiber and a high splice loss.

Arc power decides the amount of power delivered into the fusion area by the arc.

Splice loss increase: reasons and corrective measures

CHARACTERSTIC OF KEYMAN S1 SPLICING MACHINE

Characteristics: 1. Slide In 5.6" Color Monitor 2. Dual Tube Heater 3. Innovative Sleeve Loader 4. RoHS Compliant 5. Large Capacity Battery & Level Meter 6. Light Weight 7. Compact Size

Alignment: Core-to-Core Alignment Applicable Fibers: SMF(ITU-T G. 652), MMF(ITU-T G. 651), DSF(ITU-T G. 653), NZDSF(ITU-T G. 655) Fiber cleave length: 250um (Coat): 8 ~ 16mm; 250um ~ 1000um: 16mm Typical splice loss: SMF: 0.02dB, MMF: 0.01dB, DSF: 0.04dB, NZDSF: 0.04dB Return Loss: > -60dB Splice Time (typical): SPLICE: 9 sec, Tube Heat: 26 sec with S-160(60mm) Tube Program: SPLICE mode: 40; Heat mode: 13 Operating Altitude: 0 ~ 5000 m above sea level Operating Temperature: -10 ~ +50'C 95% RH (non-condensing) Wind Protection: 15 m/s Power: DC 14.8V Battery (5600 mAHr), 100 ~ 240VAC Charger Battery Life (typical): 100 cycle with S-1B, 300 cycle with S-SB Electrode: > 3000 times Tension Test: 2N / (4.4N - optional) Size (mm): 150 × 190 × 120 Weight (Kg): 2.6Kg (with battery)

EXPERIMENTS

CUTBACK METHOD:

Among the most common methods to measure fusion splice loss in the laboratory is cutback measurements. This measurement scheme consists of a calibration step and a measurement step.

Measurement is performed followed by calibration. The splice loss Γ splice can be expressed in dB

units as:

Γ splice=10 log10

Pcal

Pmeas

Where Pmeas and

Pcal are the powers measured during the measurement and calibration stages, respectively. Since the optical power measured during calibration must exceed that during

measurement, Γ splice will be a positive number.An accurate measurement was obtained by the

cutback method is described above. The experimental setup used is shown below.

PROCEDURE :

A He-Ne Laser source at 632.8 nm was used as source. The power was coupled to the fiber using a microscope objective. A large piece of fiber 4 was taken and the power was measured at the other end. Then a piece of about 4 - 5 inches was broken from the far end and then spliced with the input fiber. The output power was measured again. Using these measured values of power experimentally measured loss for each splice was calculated with the help of above formula. A cladding mode stripper (liquid Paraffin) was used at all places where jacket was removed to avoid the power coupled due to cladding modes.

1. Measurement of splice loss with splice between similar and dissimilar fiber

S no. Fiber 1 Fiber 2 Power before Splicing (mW)

Power after Splicing (mW)

Loss (dB)

1 MMF MMF 5.18 3.87 1.7622 SMF SMF 3.08 1.98 1.9243 MMF SMF 5.99 2.64 3.6544 SMF MMF 3.16 2.23 3.095

2. VARIATION IN SPLICE LOSS WITH ARC TIME

When transmitting and receiving both fiber are multimode fiber (MMF-MMF)

S NO. ARC TIME(ms) Power (mW)before splice

Power(mW)after splice

Loss (dB)

1 800 6.76 3.74 2.5642 1200 6.76 3.98 2.3343 1800 6.76 4.25 2.0124 2400 6.76 3.98 2.3265 2900 6.76 3.63 2.7366 3500 6.77 3.31 3.1657 4000 6.76 3.01 3.512

MMF-SMF

S no. ARC TIME(ms) Power(mW)before splice

Power(mW) after splice

Loss (dB)

1 800 6.56 1.58 4.142 1200 6.56 3.39 2.863 1600 6.56 4.68 1.464 2500 6.56 5.31 0.915 3000 6.56 4.80 1.356 3500 6.56 4.15 1.987 4000 6.56 3.66 2.53

3. Variation in splice loss with Arc power

When transmitting and receiving fiber are multimode fiber (MMF-MMF)

S no. Arc power bit Power(mW)Before splice

Power(mW)After splice

Loss (dB)

1 10 5.45 4.45 0.8762 15 5.45 4.65 0.6893 20 5.45 4.72 0.6224 25 5.45 4.64 0.6965 30 5.45 4.37 0.9586 35 5.45 3.71 1.66

GRAPHS:

500 1000 1500 2000 2500 3000 3500 4000 45000

0.51

1.52

2.53

3.54

loss vs arc time for MMF-MMF

arc time (ms)

loss

in d

B

500 1000 1500 2000 2500 3000 3500 4000 45000

0.51

1.52

2.53

3.54

4.5

loss vs arc time for MMF-SMF

arc time in ms

loss

in d

B

500 1000 1500 2000 2500 3000 3500 40000

0.20.40.60.8

11.21.41.61.8

loss vs arc power for MMF-MMF

power in bit

loss

in d

B

7. RESULTS

1. Splice loss for different combination of fiber is observed . It was observed the loss for

similar fiber splice was less than the loss of dissimilar fibers.

2. Arc time variation is more sensitive as in case of MMF-SMF than MMF-MMF .In both the

case we found a Arc time at which the loss is minimum.

3. Selection of Arc power in splicing is also critical as we can see graph for this case.

8 . Discussion:

Coupling from one fiber to another depend on the mode field diameter which depend on fiber parameter and wave length of laser. Mode field diameter is different in case of MMF and SMF so we can expect more difference in the power coupling. The loss is significant different when we exchange the transmitting fiber with receiving fiber and vice versa.

9. REFERENCES

1. User Manual of Keyman F1 splicer (company ILSINTECH high precision technology)2. “Small Fusion Splicer and Fiber Cleaver” by Yoshinori Iwashita et al. For Precision instrument product department.3. “Small Fusion Splicer and Fiber Cleaver” by Yoshinori Iwashita et al. For Precision instrument product department.

4. “Introduction to Fiber Optics” Prof. A.K Ghatak and Prof. K.Thyagarajan (Cambridge University 5. “Introduction to Fiber Optics” Prof. A.K Ghatak and Prof. K.Thyagarajan (Cambridge University Press)Minimization of Splice Loss Between a Single Mode Fiber and an Erbium Doped Fiber” by Salil Pradhan, Amir Mazloom, John Arbulich and K. Srihari, PhD. (IEEE Electronic Components and Technology Conference.)

PART 2 Study of mini-OTDR (E6000C company: Agilent technology)

INTRODUCTION

An optical time-domain reflectometer (OTDR) is an optoelectronic instrument used to characterize an optical fiber. An OTDR injects a series of optical pulses into the fiber under test. It also extracts, from the same end of the fiber, light that is scattered (Rayleigh backscatter) or reflected back from points along the fiber.An OTDR may be used for estimating the fiber's length and overall attenuation, including splice and mated-connector losses. It may also be used to locate faults, such as breaks, and to measure optical return loss.The optical dynamic range of an OTDR is limited by a combination of optical pulse output power, optical pulse width, input sensitivity, and signal integration time. Higher optical pulse output power, and better input sensitivity, combine directly to improve measuring range,

Working principle of OTDR

An OTDR combines a laser source and a detector to provide an inside view of the fiber link. The laser source sends a signal into the fiber where the detector receives the light reflected from the different elements of the link. This produces a trace on a graph made in accordance with the signal received, and a post-analysis event table that contains complete information on each network component is then generated. The signal sent is a short pulse that carries a certain amount of energy. A clock then precisely calculates the time of flight of the pulse, and time is converted into distance—knowing the properties of this fiber. As the pulse travels along the fiber, a small portion of the pulse’s energy returns to the detector due to the reflection of the connections and the fiber itself. When the pulse has entirely returned to the detector, another pulse is sent—until the acquisition time is complete. Therefore, many acquisitions will be performed and averaged in a second to provide a clear picture of the link’s components.

After the acquisition has been completed, signal processing is performed to calculate the distance, loss and reflection of each event, in addition to calculating the total link length, total

link loss, ORL and fiber attenuation. The main advantage of using an OTDR is the single-ended test—requiring only one operator and instrument to qualify the link or find a fault in a network.

Figure 1 below illustrates the block diagram of an OTDR.

Parameters that can be measured with the OTDR

The location (distance) of events on the link,the end of the link or a break, The attenuation coefficient of the fiber in the link, The loss of an individual event(for example a splice), or total end to end loss of the link, The magnitude of the reflection (or reflectance) of an event, such as a connector.

Events

Events are changes in the fiber causing the trace to deviate from a straight line. Events can be Reflective or Non-Reflective.Reflective Events Reflective Events occur when some of the pulse energy reflected ,for example at a connector. Reflective Events produce a spike in the trace (you see a steep rise and fall in the graph: see the first diagram below).Non-Reflective Events Non-Reflective Events occur at parts of the fiber where there is some loss but no light is reflected. Non-Reflective Events produce a dip on the trace (see the seconddiagram below).

OTDR Resolution

Instrument resolution is a measure of how close two events can be spaced and still be recognized as two separate events. The duration of the measurement pulse and the data sampling interval create a resolution limitation for OTDRs: the shorter the pulse duration and the shorter the data sampling interval, the better the instrument resolution,

A trace obtained from the OTDR showing various losses like bend loss, splice loss, connector loss and end of the fiber is shown below:

The following parameters are measured between the marker A and marker B. the change in position of markers change the recorded values :

1. 2pt.L : 2-point loss between the markers. This indicate the difference in power level between the two markers.

2. 2pt.atten : 2-point attenuation. This indicates the two point loss per unit length.3. LSA-Attn : LSA attenuation indicate least square approximation for the fiber loss per unit

length between the markers.4. ORL: optical return loss which indicates the fraction of power reflected to the mini-

OTDR.5. Ins.L. at A/B: this indicates the insertion loss of event close to the marker.6. Refl. at A/B : the return loss of event close to the marker.

7. Cum.L.to A/B: the cumulative loss between the initial backscatter value interpolated to the start of fiber and the marker point.

The selection of parameters in the measurement settings screen depends on the requirements. It is given as follows :

1. Range: by selecting auto in the range display the OTDR itself selects the suitable measurement range for the fiber. Selection can also be made from the predefined ranges or the input range of our choice.

2. Pulse Width: Short pulse improves the resolution but longer pulses are required for higher dynamic range of our choice.

3. Wavelength : the available wavelength depends on how our module has been configured. It is meaningful if we a dual wavelength OTDR module.

4. Meas. Mode: The measurement mode may be real time for updating the settings while making the measurements or Averaging to reduce noise level or Continue to continue averaging the measurement that is stopped.

5. Scatter Coefficient: it indicates how much light would be scattered back in the fiber which effects the return loss and reflectance measurements.

6. Refractive Index: It influences the distance scale of OTDR. Generally it is set to any value between 1.0 and 2.0. we can select the refractive indices of selected cable vendors from the dialog box or manually input a desired value.

7. Avg time: larger averaging time increase the dynamic range by reducing the noise floor of the OTDR. The measurement is stopped automatically when this time has elapsed.

8. Optimize mode: Resolution for short fiber, dynamic for long fibers or standard mode which is compromise for the above two modes.

9. Maximum data points: Higher values improves the resolution but limits the number of traces that can be stored in the internal flash memory.

10. Front C. Thres: The front connector threshold indicates the threshold for reflectance of front connector. If the reflectance is above the threshold then a warning message is displayed.

11. Refl. Thres : Events with the reflection above threshold are displayed in the event bar and event table.

12. Nonrefl.Thres: Events with an insertion loss above this threshold are displayed in the event abr and table.

13. End Thres: The first event with an insertion loss greater than or equal to this value is declared as type end and all subsequent events are ignored. It is like setting the fiber end.

TRACE ANALYSIS

1.Measurement of reflectance of existing events

1) Move the active marker to an event.2) select the [ANALYSIS]<ANALYSE REFLECTANCE> menu option.

3) Set the level-markers for measuring reflectance.4) Read the reflectance for the event in the marker information window.

2.Measurement of insertion loss

1 Move the active marker to an Event. 2 Select the [ANALYSIS]<ANALYZE INSERTION LOSS> menu option. 3Set the Level-markers for Measuring Insertion Loss properly.4 Read the Insertion Loss for the Event in the Marker Info. Window. The Insertion Loss is written at Ins. L. at A (or Ins. L. at B, depending in the current marker).

EXPERIMENTS

1. To find break point or fiber length of given fiber spool and FIBER LINKS

OBSERVATIONS

When wavelength selected 1550 nm

S NO. Length of fiber link

Refractive index

Wavelength nm

Threshold dB

Break found (KM)

1 0.5 1.4718 1550 3.0 0.5212 1.0 1.4718 1550 3.0 0.9883 2.0 1.4718 1550 3.0 1.9874 Unknown 1.4718 1550 3.0 0.7855 Unknown 1.4718 1550 3.0 10.906 Unknown 1.4718 1550 3.0 0.198

Observations after changing wavelength to 1310 nm

S NO. Length of fiber link

Refractive index

wavelength (nm)

threshold dB

Break found (KM)

1 0.5 1.4718 1310 3.0 0.5112 1.0 1.4718 1310 3.0 0.9813 2.0 1.4718 1310 3.0 1.9474 Unknown 1.4718 1310 3.0 0.7635 Unknown 1.4718 1310 3.0 10.906 Unknown 1.4718 1310 3.0 0.198

2. TO FIND DIFFERENT EVENT IN THE COMBINATION OF FIBER SPOOL

Three fiber spool are joint using connector ,here combination is (1km +2 Km + 0.5km)

For wavelength (ʎ= 1550nm) and pulse width (100µs)

S no. event Location(km) Reflectance(dB) Insertion loss dB

Attenuation Loss dB/km

Cumulative loss dB

1 Reflective 0 -22.64 0 0.609 ----2 Reflective 1.020 -23.07 0.471 0.581 0.6893 Reflective 2.043 -58.50 -0.009 0.581 1.7514 Reflective 3.038 -23.60 0.50 0.566 2.1855 Reflective 3.565 -18.60 ---- ---- 2.437

For wavelength (ʎ= 1310nm) and pulse width (100µs)S no. event Location(km) Reflectance(dB) Insertion

loss dBAttenuation Loss dB/km

Cumulative loss dB

1 Reflective 0 -21.64 0 0.632 ----2 Reflective 1.020 -24.07 0.481 0.681 0.7893 Reflective 2.043 -58.20 -0.009 0.621 1.9514 Reflective 3.038 -24.60 0.506 0.613 2.4855 Reflective 3.565 -17.60 ---- ---- 2.737

3. To see the event of fusion(non reflective) link between MMF and SSF

For (ʎ= 1310nm)

s.no event Location km Reflectance dB

Insertion Loss dB

Attenuation loss dB/km

Cumulative loss dB

1 Reflective 0 -24.85 0.0 --- --2 Non

Reflective0.775 ---- 0.043 0.352 0.965

3 Reflective 10.900 -46.80 --- ---- 4.67

For (ʎ= 1550nm)

s.no event Location km Reflectance dB

Insertion Loss dB

Attenuation loss dB/km

Cumulative loss dB

1 Reflective 0 -23.85 0.0 --- --2 Non

Reflective0.775 ---- 0.05 0.203 0.965

3 Reflective 10.900 -36.28 --- ---- 4.67

4. Comparison of loss created by splicing machine for different offset with the OTDR reading

s.no. Offset dB Location km reflectance Insertion loss Attenuation loss dB/km

Cumulative Loss dB

1 0.5 0.775 --- 0.32 0.201 4.912 1.0 0.775 --- 0.52 0.200 4.893 1.5 0.774 --- 0.86 0.200 4.914 2.0 0.775 --- 0.92 0.201 5.015 2.5 0.775 --- 1.32 0.201 5.036 3.0 0.775 ---- 1.50 0.203 5.217 3.5 0.775 ---- 1.75 0.204 5.61

5. Reading for bending loss , here fiber is wrapped around a torch having diameter 3cm

s.no. No. of turnsAround torch

Location km reflectance Insertion loss Attenuation loss dB/km

Cumulative Loss dB

1 5 0.775 --- 0.12 0.206 4.762 10 0.775 --- 0.17 0.203 4.893 15 0.774 --- 0.21 0.202 4.914 20 0.775 --- 0.26 0.201 4.965 25 0.775 --- 0.32 0.201 4.996 30 0.775 ---- 0.40 0.203 5.117 35 0.775 ---- 0.45 0.204 5.21

6. To find resolution of OTDR

Minimum pulse width in the given OTDR is τ =10 nsRefractive index chosen n = 1.4718

Velocity of light in medium vg=cn

Vg=3 X 108

1.4718 =2.04 x 108 m/s

ΔL = Vg x τ = 2.04 meter

Theoretically it is expected resolution should be 2.04 meter

Observation 1. When only one splice point is there

For (ʎ= 1310nm)

s.no event Location km Reflectance dB

Insertion Loss dB

Attenuation loss dB/km

Cumulative loss dB

1 Reflective 0 -24.85 0.0 --- --2 Non

Reflective0.775 ---- 0.043 0.352 0.965

3 Reflective 10.900 -46.80 --- ---- 4.67

2. When two splice points are 6 meter apart

For (ʎ= 1310nm)

s.no event Location km Reflectance dB

Insertion Loss dB

Attenuation loss dB/km

Cumulative loss dB

1 Reflective 0 -24.64 0.0 --- --2 Non

Reflective0.775 ---- 0.053 0.365 0.965

3 Reflective 10.900 -46.89 --- ---- 4.66

Results:

1. Break was found for six fiber links three unknown and three known. experimentally founded fiber length was quite close to the length of the known fiber. As we change wavelength of OTDR fiber length do not affect much.

2. For combination of fiber spool connected by connector event was seen. All event was reflective typeHere cumulative loss was also found. Insertion loss produced by connector was around 0.4-0.5 dB.

3. For finding non reflective event, two fibers were fussed together and insertion loss was found 0.045 dB. We can see attenuation loss is minimum at wavelength 1550 nm i.e. 2.03 dB/km.

4. Loss showed by the splicing machine was greater than the loss showed by otdr for a fiber joint.5. As we keep on increasing no. of turns of fiber around torch, loss due to bending also increase

6. Theoretically it was expected that resolution should be 2.01 meter. but experimentally at least 6 meter resolution was not visible because otdr was showing only one non refractive event instead of two separated by a distance of 6 meter.

References

1. User manual of E6000C mini-otdr ( agilent technologies).2. “Introduction to Fiber Optics” Prof. A.K Ghatak and Prof. K.Thyagarajan (Cambridge University Press)

3. “Optical fiber communication” John M. Senior

4. “Small Fusion Splicer and Fiber Cleaver” by Yoshinori Iwashita et al. For Precision instrument product department. 5 . “Application note on Splice Loss” by Ravi Shankar, Sudipta Bhaumik, Abhay Arora. For Sterlite Optical Technologies.6. “optical fiber communication” G. Keiser7. Minimization of Splice Loss Between a Single Mode Fiber and an Erbium Doped Fiber” by Salil Pradhan, Amir Mazloom, John Arbulich and K. Srihari, PhD. (IEEE Electronic Components and Technology Conference.)