THORLABS Telesto Series User manual

SD-OCT Base Unit
Spectral Domain
OCT System Base Units:
Telesto, Ganymede, and
Callisto Series
User Manual

Original User Manual – not translated

SD-OCT Base Unit
Table of Contents
Chapter 1Introduction.....................................................................................................................1
1.1.Safety.......................................................................................................................... 2
1.2.Care and Maintenance .............................................................................................. 3
Optical Cleaning .............................................................................................................. 4 
Fiber Cleaning Techniques Using the FBC1 ................................................................... 4
Service ............................................................................................................................ 6
Accessories and Customization ...................................................................................... 6
Chapter 2Setup................................................................................................................................7
2.1.Unpacking .................................................................................................................. 7
2.2.System Connections................................................................................................. 7
Base Unit Connections .................................................................................................... 7
Internal Electrical Connections ....................................................................................... 7
Electrical Interfaces to Probe .......................................................................................... 8
2.3.Optical Interface to Probe......................................................................................... 8
2.4.System Installation.................................................................................................... 9
Enable External Trigger ................................................................................................ 15
Chapter 3Description....................................................................................................................16
3.1.Tutorial ..................................................................................................................... 16
Theory ........................................................................................................................... 17
Thorlabs SD-OCT System Technology ......................................................................... 18
Polarization-Sensitive Optical Coherence Tomography ............................................... 19
Nomenclature in OCT imaging ...................................................................................... 20
3.2.OCT Base Unit Components .................................................................................. 22
Base Unit ....................................................................................................................... 22
PC with Graphical User Interface .................................................................................. 22
SDK ............................................................................................................................... 23
Imaging Scanner (Accessory) ....................................................................................... 24
OCT-STAND (Accessory) ............................................................................................. 26
Chapter 4System Operation.........................................................................................................28
4.1.Starting the System................................................................................................. 28
4.2.Basic Adjustments .................................................................................................. 28
Adjusting the Focus ....................................................................................................... 28
Adjusting the Reference Intensity ................................................................................. 29
Adjusting the Reference Length .................................................................................... 29
4.3.Advanced Adjustments .......................................................................................... 31
Focus and Choice of Objective Lens ............................................................................ 31
Imaging through Refractive Media ................................................................................ 32
Optimizing the Sensitivity .............................................................................................. 33
Reflecting Surfaces and Interfaces ............................................................................... 33
Rough Surfaces ............................................................................................................ 34
4.4.Shutting Down the System..................................................................................... 34
4.5.Example Images ...................................................................................................... 35
Chapter 5Imaging Artifacts..........................................................................................................38
5.1.Saturation and Non-Linearity ................................................................................. 38
5.2.Wrong Reference Intensity Setting........................................................................ 39
5.3.Autocorrelation........................................................................................................ 40

SD-OCT Base Unit
5.4.Multiple Scattering .................................................................................................. 41
5.5.Phase Wrapping and Fringe Washout................................................................... 42
5.6.Flipped Image .......................................................................................................... 43
5.7.Shadowing ............................................................................................................... 44
5.8.Image Distortion by Refractive Media ................................................................... 45
The Group Refraction Index .......................................................................................... 46
Measurement Depth in OCT Systems .......................................................................... 47
Distortions in the Image ................................................................................................ 48
Chapter 6Troubleshooting...........................................................................................................50
6.1.Changing the Input Fuses ...................................................................................... 51
Chapter 7Certifications and Compliance...................................................................................52
7.1.Declaration of Conformity GAN2x0 Series Base Units........................................ 52
7.2.Declaration of Conformity GAN6x0 Series Base Units........................................ 53
7.3.Declaration of Conformity TEL2x0 Series Base Units ......................................... 54
7.4.Declaration of Conformity TEL2x0PS Series Base Units .................................... 55
7.5.Declaration of Conformity TEL3x0 Series Base Units ......................................... 56
7.6.Declaration of Conformity CAL1x0 Series Base Units ........................................ 57
Chapter 8Warranty........................................................................................................................58
8.1.Lasers and Imaging Systems................................................................................. 58
8.2.Non-Warranty Repairs ............................................................................................ 58
8.3.Warranty Exclusions............................................................................................... 58
Chapter 9Specifications...............................................................................................................59
Chapter 10Mechanical Drawings...................................................................................................61
Chapter 11Regulatory.....................................................................................................................62
11.1.Waste Treatment is Your Own Responsibility...................................................... 62
11.2.Ecological Background .......................................................................................... 62
Chapter 12Thorlabs Worldwide Contacts....................................................................................63

SD-OCT Base Unit Chapter 1: Introduction
Rev E, November 7, 2018 Page 1
Chapter 1 Introduction
ATTENTION
Please read the instruction manual carefully before operating the OCT base unit. All statements
regarding safety and technical specifications will only apply when the unit is operated correctly.
This equipment is intended for laboratory use only and is not certified for medical applications,
including but not limited to life support situations.
Refer to this manual whenever the following symbols are encountered on the OCT base unit:
Attention symbol indicates that additional information is given in this manual.
Laser Safety symbol indicates that laser radiation is present.
This manual describes the SD-OCT base units of the Telesto, Ganymede, and Callisto Series.
If not specified, the base units of the Telesto-PS Series are incorporated in the Telesto Series.
ATTENTION
Check the supply voltage of the system before plugging in the computer. Make sure the included
power cords for the base unit, computer, and monitor are connected to a properly grounded
outlet (100 – 240 VAC; 50 – 60 Hz).
Transportation and delivery may cause the OCT base unit to be warm or cool upon receipt.
Please wait for the system to reach room temperature before attempting to operate.
Operate this system on a flat, dry, and stable surface only.
WARRANTY WARNING
Do not open the base unit, imaging scanner or PC. There are no user serviceable parts in this
product. Opening the device will void your warranty. Any modification or servicing of this
system by unqualified personnel renders Thorlabs free of any liability. This device can only be
returned when packed into the complete original packaging, including all foam packing inserts.
If necessary, ask for replacement packaging.

SD-OCT Base Unit Chapter 1: Introduction
Page 2 MTN012389-D02
1.1. Safety
SHOCK WARNING – HIGH VOLTAGE
Before applying power to the system, make sure that the protective conductor of the three-
conductor mains power cord is correctly connected to the protective earth contact of the socket
outlet. Improper grounding can cause electrical shock resulting in severe injury or even death.
Make sure that the line voltage rating agrees with your local supply and that the appropriate
fuses are installed. Fuses should only be changed by qualified service personnel. Contact
Thorlabs for assistance. Do not operate without cover installed. Refer servicing to qualified
personnel.
ATTENTION
Do not obstruct the air-ventilation slots in the computer housing. Do not obstruct air-ventilation
into the bottom of the base unit or out of the exhaust fan on the rear of the unit.
Mobile telephones, cellular phones, or other radio transmitters are not to be used within the
range of three meters of this unit, since the electromagnetic field intensity may exceed the
maximum allowed disturbance values according to IEC 61000-6-1:2005.
The safety of any system incorporating the equipment is the responsibility of the assembler of
the system.
If equipment is used in a manner not specified by the manufacturer, the protection provided by
the equipment may be impaired.
LASER RADIATION WARNING
Laser emission may be emitted
a) from the scan lens of a scanner (intended use)
b) from the back of the base unit when the fiber cap is removed and the fiber disconnected
c) from the output of the fiber when the fiber is not connected to a scanner
Do not look into the optical output when the device is operating. The laser radiation is not visible
to the human eye and can cause serious damage to your eyesight.
The laser class information is also stated on the laser safety labels on the back of the housing.
Example given for class 1M LASER product:
INVISIBLELASERRADIATION

DONOTSTAREINTOBEAMORVIEW
DIRECTLYWITHOPTICALINSTRUMENTS

CLASS1MLASERPRODUCT

CLASSIFIED ACCORDINGTODINEN60825‐1:2014

SD-OCT Base Unit Chapter 1: Introduction
Rev E, November 7, 2018 Page 3
1.2. Care and Maintenance
Handle the system with care during transportation and unpacking. Banging or dropping the system can damage
the unit or lower system performance. If the system is mishandled during shipment, the optical components may
become misaligned, which could lead to a decrease in image quality. If this occurs, the system will need to be
realigned by qualified personnel. Please contact Thorlabs technical support for more information.
 Do not store or operate in a damp, closed environment.
 Do not store or operate on surfaces that are susceptible to vibrations.
 Do not expose to direct sunlight.
 Do not use solvents on or near the equipment.
 Keep away from dust, dirt, and air-borne pollutants (including cigarette smoke). The system is not
designed for outdoor use. Protect the equipment from rain, snow, and humidity.
 Do not expose to mechanical and thermal extremes. Protect the equipment from rapid variation in
temperature.
 Handle all connectors, both electrical and optical, with care. Do not use unnecessary force, as this may
damage the connectors.
 Handle the optical fiber with care. Mechanical stress can decrease performance and potentially destroy
the fiber. Continual bending of the optical fiber can cause damage. It is important, therefore, to keep
the optical fiber patch cable as straight as possible to minimize bending.
Note: The most common cause of low signal intensity is contamination of the fiber due to airborne pollutants.
To minimize exposure, avoid unnecessarily disconnecting the optical fiber patch cable. In addition, it is advisable
to check the fiber before making other adjustments to the optical system, such as changing the focus or optical
path length. Be sure to check the patch cord for a loose connection, and make sure that the fiber is kept as
straight as possible.
All lasers, especially lasers with resonator cavities that are defined by mechanical tolerances, are delicate
precision instruments and must be handled accordingly. The OCT base unit is designed to withstand normal
transportation and operating conditions. Do not move the system while it is connected and in operation.

SD-OCT Base Unit Chapter 1: Introduction
Page 4 MTN012389-D02
Optical Cleaning
Good performance and image quality of the OCT imaging system relies on clean optical connections. Whenever
using the Thorlabs OCT system, the following guidelines for optical fiber connection should be followed:
1) Always make sure that the light source is switched off when you clean the fiber.
2) Always inspect and clean the fiber end before plugging it into a receptacle.
3) Always cover the fiber end that is not in use with a fiber cap or dust protection cover.
The cleaning procedure sucess could be visualized using a fiber inspection scope
Figure 1 Fiber Inspection Scope FS201
Fiber Cleaning Techniques Using the FBC1
This section details how to clean fiber bulkheads and fiber connectors using the FBC1 one-step cleaner.
Using Extended Mode
Figure 2 FBC1 Extended Mode
To use extended mode, pull the tip outward while simultaneously pushing down on the lock button. Extended
mode is useful for panels with multiple bulkhead connectors or other tight spaces.

SD-OCT Base Unit Chapter 1: Introduction
Rev E, November 7, 2018 Page 5
Cleaning Fiber Bulkheads
Figure 3 Cleaning Fiber Bulkheads
Remove the guide cap completely from the device, and insert the tip of the cleaner into the bulkhead connector.
Push the case to start the cleaning process; a click indicates that the cleaning is complete.
Cleaning Fiber Connectors
Figure 4 Cleaning Fiber Connectors
Open the cover on the guide cap, and insert the fiber connector over the guide cap. Push the case to start the
cleaning process; a click indicates that the cleaning is complete.

SD-OCT Base Unit Chapter 1: Introduction
Page 6 MTN012389-D02
Service
Only trained and approved Thorlabs personnel are allowed to service the system. Please contact Thorlabs
technical support for more information.
Accessories and Customization
The OCT base unit can easily be adapted for custom interfaces. To achieve the listed specifications, however,
this system should only be used with the accessories that Thorlabs provides. Any modification or maintenance
by unqualified personnel will render the warranty null and void, leaving Thorlabs free of liability. Please contact
Thorlabs technical support for questions on customization.

SD-OCT Base Unit Chapter 2: Setup
Rev E, November 7, 2018 Page 7
Chapter 2 Setup
2.1. Unpacking
Carefully unpack the components from the transport boxes. Make sure that all components are delivered
according to the packing list included in the transport box. After unpacking, store the packing cartons and inserts.
You may need them in case of a service or upgrade of your OCT system.
2.2. System Connections
Base Unit Connections
All OCT base unit connections are located in the rear (see Figure 5).
Figure 5 Rear View of OCT Base Unit
A. Power Plug
B. USB Data Port to Connect PC (USB 2.0 Type B Interface)
C. Fiber Connection to the Imaging Scanner (FC/APC)
o In Telesto-PS Series base units a fiber cable is permanently installed
D. Auxiliary Fiber Connection to Imaging Scanner (FC/APC) – Not in Telesto Series and some
Ganymede Series base units
E. Probe Connection Port (LEMO, 19 Pin)
F. Auxiliary Connection Port (LEMO, 14 Pin)
G. CameraLink Connection:
o Med/Full – Only in some Ganymede and some Telesto Series Base Units
o Camera 0 – Only in Telesto-PS Series base units (not shown above)
H. CameraLink Connection
o Base – Not in Callisto Series base units
o Camera 1 - Only in Telesto-PS Series base units (not shown above)
I. Trigger Connection SMB – Not in Callisto Series base units
Internal Electrical Connections
The USB connection to the PC is used for the control communication between the Software and base unit.
The acquisition and synchronization of the spectral information is using the CameraLink and the Trigger
connection.

SD-OCT Base Unit Chapter 2: Setup
Page 8 MTN012389-D02
Electrical Interfaces to Probe
For the connection to a scanner application there are two different interfaces available.
 The probe connection port is intended to be used together with dedicated Thorlabs imaging scanners
OCTG and OCTP.
 The auxiliary connection port is intended to be used together with dedicated Thorlabs imaging
scanner OCTH and furthermore allows the use of a custom scanner. It hosts two analog signals for
driving separate actuators (e.g. Galvanometer scanner), communication lines and supply voltages.
Electrical Probe Connection Interfaces
Probe Connection Port Lemo ECG.2B.319.CLL
Auxiliary Connection Port Lemo ECA.1B.314.CLL
Table 1 Electrical Probe Connection Interface
Please contact Thorlabs’ tech support for information regarding the pin configuration.
2.3. Optical Interface to Probe
The base unit can incorporate one or two FC/APC fiber interfaces depending on the internal fiber architecture
(see also chapter 3.1.2):
 Base units with an integrated circulator-support-only port.
 Base units comprising an internal coupler support two FC/APC interfaces. These ports could be used
to build a dual path setup with minimum optical loss. The optical path length difference between the two
ports is not defined.
 The Telesto-PS Series base units already comes with an attached polarization maintaining fiber and no
additional fiber is needed.
If not different due to customization the single mode fiber used in the base units is given in Table 2:
Optical Probe Connection Interface
Base Unit Series Fiber Connector Single Mode Fiber
Callisto / Ganymede FC/APC Nufern 780
Telesto FC/APC Corning SMF28 Ultra
or Corning HI-1060
Telesto-PS Permanently Attached to
Base Unit
Corning PANDA PM13-U25A
Key Aligned to Slow Axis
Table 2 Optical Probe Connection Interface

SD-OCT Base Unit Chapter 2: Setup
Rev E, November 7, 2018 Page 9
2.4. System Installation
ATTENTION
Make sure the included power cords for the base unit, computer and monitor are connected to a
properly grounded outlet (100 – 240 VAC; 50 – 60 Hz).
Transportation and delivery may cause the OCT base unit to be warm or cool upon receipt.
Please wait for the system to reach room temperature before attempting to operate.
Operate this system on a flat, dry, and stable surface only.
1) Install the PC, monitor, mouse and keyboard according to the documentation provided by the PC
manufacturer.
2) If applicable, assemble the OCT-STAND as described in the documents provided in the OCT-STAND
box.
3) If applicable, mount the scanner in the OCT-STAND by sliding the dove tail at the back of the scanner
into the dove tail slide of the OCT-STAND.
Figure 6 Mounting the OCTG Scanner into the Dove Tail Slide of the OCT-STAND

SD-OCT Base Unit Chapter 2: Setup
Page 10 MTN012389-D02
4) Connect the CameraLink and the SMB cables between the base unit and the PC (not for CAL-Series
base units).
a. In the Telesto-PS Series base units connect the long SMB cable between the base unit and
the SMB tee connector which is plugged into the PC. Use the short cable to connect the
second framegrabber with the open port of the SMB tee connector.
Figure 7 Connection of SMB to both Framegrabber Cards (Telesto-PS Series Base Units only)
5) Attach the USB cable to the base unit and to the PC.
6) Connect the power supply plug to the socket of the base unit and connect the other end to an electrical
outlet.

SD-OCT Base Unit Chapter 2: Setup
Rev E, November 7, 2018 Page 11
7) Attach the electric connection cable to the imaging scanner.
Align the red dot of the plug to the alignment mark of the electric connection port of the scanner
(e.g.: OCTG).
Figure 8 Plugging the Electric Connector into the Scanner
Figure 9 Electric Connector Plugged into the Scanner
Push the connector into the receptacle until a “click” sound is heard.

SD-OCT Base Unit Chapter 2: Setup
Page 12 MTN012389-D02
8) Connect the fiber to the imaging scanner.
ATTENTION
When installing the fiber, make sure that the fiber tip does not get contaminated by dust.
Do not touch the fiber tip!
Remove the dust caps from one fiber end and from the FC/APC fiber connection at the imaging
scanner. Store these with the system packaging.
Inspect the fiber and clean it according to chapter 1.2.2.
Figure 10 Fiber Connection to the Imaging Scanner
A) Slide the fiber tip into the center bore of the fiber connection.
B, C) The fiber needs to be oriented in rotation so that the alignment key slides into the mating
part of the probe connector as shown in Figure 10C.
NOTE: If the key is not properly aligned, you will still be able to secure the fiber, but there
will be significant light losses produced by this incorrect connection.
D) Secure the fiber connection by turning the lock cap clockwise. No force is needed for this
operation.
A
DC
B

SD-OCT Base Unit Chapter 2: Setup
Rev E, November 7, 2018 Page 13
9) Attach the electric connection cable to the base unit.
Align the red dot upwards, facing the alignment mark in the base unit.
Figure 11 Installing the Electric Connection Cable at the Base Unit
Push the connector into the receptacle until a “click” sound is heard.

SD-OCT Base Unit Chapter 2: Setup
Page 14 MTN012389-D02
10) Connect the fiber to the base unit. (Not in Telesto-PS Series base units.)
ATTENTION
When installing the fiber, make sure that the fiber tip does not get contaminated by dust.
Do not touch the fiber tip!
Remove the dust caps from the fiber end and from the FC/APC fiber connection at the base unit.
Inspect the fiber and clean it according to chapter 1.2.2.
Figure 12 Fiber Connection to the Base Unit
A) Slide the fiber tip into the center bore of the fiber connection.
B), C) The fiber needs to be oriented in rotation, so that the alignment key slides into the mating
part of the probe connector.
D) Secure the fiber connection by turning the lock cap clockwise. No force is needed for this
operation.
A
DC
B

SD-OCT Base Unit Chapter 2: Setup
Rev E, November 7, 2018 Page 15
11) Pull the protective cap off the scan objective.
Do not touch the optical surface of the lens.
Figure 13 Protective Cap Removal
Enable External Trigger
To enable the option to use an external trigger, a tee connector must be inserted into the trigger connection to
allow inserting the trigger signal.
The location of this connector is shown in Figure 14. This option is not available in Callisto and Telesto-PS
Series base units.
ATTENTION
To make use of the external trigger the checkbox to activate the external trigger mode under
"Hardware" in the "Settings" dialog for external A-scan triggering must be active.
If not, the internal trigger is still active and the scanner process will be disturbed.
For more details, please refer to the OCT software manual.
Figure 14 External Trigger Attached using an SMB Tee Connector

SD-OCT Base Unit Chapter 3: Description
Page 16 MTN012389-D02
Chapter 3 Description
3.1. Tutorial
Frequency Domain Optical Coherence Tomography (FD-OCT) is based on low-coherence interferometry,
which utilizes the coherent properties of a light source to measure optical path length delays in a sample.
To obtain cross-sectional images with micron-level resolution using OCT, an interferometer is set up to measure
optical path length differences between light reflected from the sample and reference arms.
There are two types of FD-OCT systems, each characterized by its light source and detection schemes;
 Time-encoded Frequency Domain OCT (teFD-OCT),
also named Swept Source OCT (SS-OCT).
 Spatially-encoded Frequency Domain OCT (seFD-OCT),
also named Fourier Transform Domain OCT (FD-OCT) and Spectral Domain OCT (SD-OCT).
Thorlabs uses the abbreviations SD-OCT for the spatially-encoded camera-based OCT systems and SS-OCT
for the time-encoded systems.
In both types of systems, light is split by a fiber coupler into the sample and reference arms of an interferometer
setup.
Back reflected light, attributed to variations in the index of refraction within a sample, recouples into the sample
arm fiber and then combines with the light that has traveled a fixed optical path length along the reference arm.
The resulting interferogram is measured by either a spectrometer (SD-OCT) or balanced photodetectors
(SS-OCT).
The frequency of the interferogram measured by the sensor is related to the depth location of the reflector in
the sample. As a result, a depth reflectivity profile (A-scan) is produced by taking a Fourier transform of the
detected interferogram. 2D cross-sectional images (B-scans) are produced by scanning the OCT sample beam
across the sample; by doing so, a series of A-scans are collected to create the 2D image. Similarly, when the
OCT beam is scanned in a second direction, a series of 2D images is collected to produce a 3D volume dataset.
Figure 15 FD-OCT Signal Processing