NKT Koheras BASIK MIKRO User manual

Koheras BASIK MIKRO
PRODUCT GUIDE
Low Noise Single Frequency Laser Module

PRODUCT GUIDE
This guide includes the following NKT Photonics Lasers:
Koheras BASIK MIKRO
Low Noise Single Frequency Laser Module
Koheras BASIK MIKRO Product Description Revision 1.1 01-2020 W-10456

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GUIDE OVERVIEW
This product guide is intended to provide functional, operational and installation
information for the Koheras BASIK MIKRO laser modules. The guide is divided
into three sections:
• Koheras BASIK MIKRO Description - introduces the laser, its functionality,
interfaces and chassis variants.
• Operating the laser – provides information and procedures on how to
connect and configure communications with the laser and manage its
operation.
• Installing the laser – includes the details on how to install the laser chassis
variants and connect optional interfaces.
Warning: Do not operate the laser before first reading and understanding all warn-
ings, cautions and handling information stated within the document:
Koheras BASIK MIKRO Safety, Handling and Regulatory Information
The paper copy of this guide is included with your laser however it can also be
downloaded from:
https://www.nktphotonics.com/lasers-fibers/support/product-manuals/
Terminology The guide may refer to the Koheras BASIK MIKRO modules as “the laser”. In
specific cases where a distinction is required, the guide will use the actual laser
model names or simply as “the module”.
Target audience This guide is for technical personnel involved in the selection, planning and
deployment of lasers in laboratory and industrial settings. The guide assumes a
reasonable knowledge level of lasers, photonic principles and electrical interface
connectivity.
Chapters inside This guide includes the following chapters:
• Chapter I “Laser description” — Describes the laser including its general
operational principles, management and interfaces.
• Chapter 2 “Communicating with the Laser” — Provides information and
procedures on how to setup a PC with the laser’s management software and
connect it to the laser.
• Chapter 3 “Turning On the Laser” — Contains procedures on how to safely
turn the laser emissions on and off using the management software.
• Chapter 4 “Using CONTROL” — Includes descriptions and procedures of all
other GUI menu and panel items.

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• Chapter 5 “Software Development Kit” — Includes descriptions and
procedures for certain key settings that can be configured using the SDK.
• Chapter 6 “Mechanical Installation” — Includes information and procedures
on how to correctly install the laser chassis. Procedures within this chapter
focus on providing adequate temperature regulation.
• Chapter 7 “Connecting the laser” — This chapter provides the information on
how to physically connect the safety interlock, power, the optical collimator,
and the optional interfaces.
• Appendices — The guide includes multiple appendices including laser
specifications, support contact details, accessory descriptions, a
configuration ID cross-reference and miscellaneous procedures supporting
the laser operation and installation.
Added information
and safety notices
Lasers are highly dangerous devices that can cause serious injury and property
damage. This guide use the following symbols to either highlight important safety
information or provide further information in relation to a specific topic.
Note: Highlights additional information related to the associated topic and/or pro-
vides links or the name of the NKT guides describing the additional information.
Caution: Alerts you to a potential hazard that could cause loss of data, or damage
the system or equipment.
Warning: The laser safety warning alerts you to potential serious injury that may
be caused when using the laser.
Revision The section records the document revision details.
Date Revision Changes
2019-09 1.0 First release - documents rewritten and overhauled from earlier releases.
2020-01 1.1 Added Appendix F - Configuration IDs. Configuration ID description and
cross-reference for standard configuration IDs.

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CONTENTS
Guide Overview ................................................................................................................... 3
Terminology ............................................................................................................ 3
CONTENTS ..............................................................................................................5
TABLES .....................................................................................................................9
FIGURES ...................................................................................................................11
PROCEDURES ........................................................................................................13
Section 1 BASIK MIKRO DESCRIPTION 15
1 Laser description ................................................................................................................17
Theory of operation .............................................................................................17
Module variants ......................................................................................................... 18
Configuration ID ................................................................................................... 18
Center wavelength .............................................................................................. 18
Tuning types ......................................................................................................... 18
Laser features ............................................................................................................ 18
Thermal tuning ..................................................................................................... 18
Fast wavelength modulation ............................................................................ 19
Operating mode ................................................................................................... 19
Auto-start .............................................................................................................. 20
Emission delay ..................................................................................................... 20
Shutdown delay .................................................................................................. 20
High temperature shutdown ............................................................................ 20
Power verification ................................................................................................ 21
Miscellaneous ............................................................................................................ 21
Power supply ........................................................................................................ 21
Safety ...................................................................................................................... 21
Accessories ........................................................................................................... 21
Optical interface ....................................................................................................... 22

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Electrical Interfaces .................................................................................................. 23
Main electrical interface .................................................................................... 24
Fast wavelength modulation input ................................................................. 24
Laser Control ............................................................................................................. 24
User interface ...................................................................................................... 24
Status LEDs ................................................................................................................26
Module labels ............................................................................................................ 27
Section 2 OPERATING THE LASER 29
2 Communicating with the Laser ...................................................................................... 31
CONTROL software .................................................................................................. 31
Installing the software ........................................................................................ 31
Software Development Kit ...................................................................................... 31
Generic User Interface ....................................................................................... 31
Connecting the laser to a PC with CONTROL .................................................. 32
Connecting the laser to a PC using the Generic User Interface .................. 34
3 Turning On the Laser ...................................................................................................... 35
Safety ........................................................................................................................... 35
Preparation ................................................................................................................. 35
Controlling the laser emissions ............................................................................ 36
Turning On the laser .......................................................................................... 36
4 Using CONTROL ............................................................................................................... 39
CONTROL overview ................................................................................................ 39
Relocating panels ............................................................................................... 40
Toggling panels .................................................................................................... 41
Connecting to the laser ...................................................................................... 41
Status panel ................................................................................................................ 41
Status indicators .................................................................................................. 42
System info ........................................................................................................... 42
Emission button ................................................................................................... 43
CONTROL settings ............................................................................................. 43

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CONTROL menu items ........................................................................................... 45
Serial monitor ....................................................................................................... 45
Application log .................................................................................................... 46
CONTROL – Control panel .....................................................................................47
Power mode ..........................................................................................................47
Current mode .......................................................................................................47
5 Software Development Kit ..............................................................................................49
Tuning the wavelength ........................................................................................... 49
Setting the operating mode .................................................................................. 50
Auto start .................................................................................................................... 50
Setting the emission delay ..................................................................................... 51
Section 3 INSTALLING THE LASER 53
6 Mechanical Installation ................................................................................................... 55
General ....................................................................................................................... 55
Heat dissipation .................................................................................................. 55
Installation method .................................................................................................. 55
Operating and storage environment ............................................................. 56
7 Connecting the laser ........................................................................................................57
Connecting the safety interlock ............................................................................57
Interlock operation ..............................................................................................57
LEMO connector ..................................................................................................57
Connecting an interlock switch ...................................................................... 58
Connecting power ................................................................................................... 59
Fast wavelength modulation input ...................................................................... 59
Slew rate ............................................................................................................... 60
Connecting the optical output .............................................................................. 60
Appendices
A Specifications .....................................................................................................................63

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B Service and support Information .................................................................................. 65
Servicing the laser ....................................................................................................65
Opening the laser chassis ................................................................................ 65
WARRANTY VOID IF REMOVED Label ......................................................... 65
Support contact details ........................................................................................... 66
Support Email ....................................................................................................... 66
Online support web-page ................................................................................. 66
Shipping address ................................................................................................ 66
C Interface pin assignments ...............................................................................................67
Main electrical interfaces ........................................................................................ 67
Fast wavelength modulation input ....................................................................... 67
D CONTROL installation ..................................................................................................... 69
Installing CONTROL .................................................................................................69
E RS-485 adapter ..................................................................................................................75
Main adapter ........................................................................................................ 75
F Configuration ID ................................................................................................................77
Module Configuration ID ....................................................................................77

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TABLES
Table 1: BASIK MIKRO output specifications.................................................................. 18
Table 2: Recommended Power Modes.......................................................................... 20
Table 3: Optical Interface Specifications ...................................................................... 22
Table 4: Connectors ............................................................................................................ 23
Table 5: Status LEDs............................................................................................................ 26
Table 6: Module labels.........................................................................................................27
Table 7: CONTROL panels and menu items ................................................................. 39
Table 8: Power adapter specifications ........................................................................... 59
Table 9: Fast wavelength modulation specifications.................................................. 60
Table 10: Optical .................................................................................................................. 63
Table 11: Mechanical dimensions .................................................................................... 63
Table 12: Operating and storage environment ............................................................ 63
Table 13: Electrical................................................................................................................ 64
Table 14: Safety and regulatory compliances ............................................................... 64
Table 15: Main electrical interface pin assignment.......................................................67
Table 16: Fast Wavelength Modulation input.................................................................67
Table 17: RS-485 adapter status LEDs .............................................................................75
Table 18: Standard BASIK MIKRO Configuration IDs ...................................................77

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FIGURES
Figure 1: Working panel of the BASIK MIKRO ................................................................17
Figure 2: Frequency response using wavelength modulation ................................. 19
Figure 3: USB-RS485 Adapter ......................................................................................... 22
Figure 4: BASIK MIKRO equipped with fiber cord and FC/APC connector ......... 22
Figure 5: Front panel electrical connections ............................................................... 23
Figure 6: Status LEDs ......................................................................................................... 26
Figure 7: Top Panel Label Locations ...............................................................................27
Figure 8: GUI Panel Navigation ....................................................................................... 39
Figure 9: Panel dragged to a new location in the main window - ......................... 40
Figure 10: Panels dragged outside the main window ................................................ 40
Figure 11: Panels dragged outside the main window .................................................. 41
Figure 12: Welcome screen and connecting ................................................................. 41
Figure 13: Status panel ....................................................................................................... 42
Figure 14: GUI Settings ....................................................................................................... 43
Figure 15: Current mode controls .................................................................................... 44
Figure 16: Auto-start check box ....................................................................................... 44
Figure 17: View setting ....................................................................................................... 44
Figure 18: Menu Items ........................................................................................................ 45
Figure 19: Serial monitor .................................................................................................... 45
Figure 20: Serial Monitor ................................................................................................... 46
Figure 21: Operating mode set to power .......................................................................47
Figure 22: Operating Mode set to Power ......................................................................47
Figure 23: Setting Register 0x2A – Wavelength ........................................................ 49
Figure 24: Setting register 0x31 – setup bits (operating mode) ............................. 50
Figure 25: Setting Register 0x31 – Setup bits (Auto-start function) ....................... 50
Figure 26: Setting Register 0x3A – Emission delay .................................................... 51
Figure 27: Mounting the laser .......................................................................................... 56
Figure 28: IRS-485 adapter connected to a door switch (open position) ............ 58

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Figure 29: Power supply .................................................................................................... 59
Figure 30: Mechanical dimensions ...............................................................................................64
Figure 31: Warranty seal .....................................................................................................65
Figure 32: RS-485 adapter ................................................................................................ 76
Figure 33: How to read the configuration ID .................................................................77
white

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PROCEDURES
Procedure 1: Connecting CONTROL to the laser........................................................ 32
Procedure 2: Connecting the Generic User Interface to the laser......................... 34
Procedure 3: Turning on the laser using CONTROL.................................................. 36
Procedure 4: Turning on the Laser using the Generic User Interface ................... 37
Procedure 5: Relocating panels ...................................................................................... 40
Procedure 6: Connecting the door interlock circuit................................................... 58
Procedure 7: Installing CONTROL.................................................................................... 69

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SECTION 1
BASIK MIKRO DESCRIPTION
This section provides a description of the laser and its chassis types. It includes the
following topics:
•“Laser description” on page 17
•“Module variants” on page 18
•“Laser features” on page 18
•“Miscellaneous” on page 21
•“Optical interface” on page 22
•“Electrical Interfaces” on page 23
•“Laser Control” on page 24
•“Status LEDs” on page 26
•“Module labels” on page 27

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1 Laser description
The Koheras BASIK MIKRO is an industrial single frequency fiber laser housed
within a micro-casing. Further, the laser and its micro-casing (referred to as a
module) is designed for integration with industrial applications where its built-in
laser control circuits can continuously monitor the laser’s performance. Using
these monitoring circuits, the laser supports applications that demand ultra-low
noise, high wavelength stability and ultra-stable single frequency operation
unaffected by mode hops.
Figure 1 Working panel of the BASIK MIKRO
The laser is designed with distributed feedback fiber laser technology and center
wavelengths that can be specified from 1535 to 1580 nm. The laser also supports
a wide tuning range of approximately 1 nm from the specified center wavelength.
Tuning is accomplished either manually through thermal tuning or using an
external signal applied at the laser’s fast wavelength modulation input port. A
varying external signal applied to the port, modulates the output wavelength.
Modulating the output wavelength can obtain improved stabilization when
compared with the free-running wavelength specification.
The standard output of the laser utilizes either standard single mode fiber or
optional polarization-maintaining fiber to improve the linear characteristics.
Improved polarization linearity is usually required when the laser output is either
externally modulated or frequency converted.
Theory of operation The BASIK MIKRO is a fiber laser that uses a fiber Bragg grating cavity to produce
an output beam operating in single mode. The center wavelength of the laser is
configurable using either thermal substrate control or optional Piezo
components. Due to the special Bragg grating, the single mode operation is
constantly maintained and is stable over the entire operating frequency band of
the laser.

Module variants
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Module variants
The Koheras BASIK MIKRO modules are available in two variants: the E15 and
C15 modules. The modules are classified by their phase noise, intensity and
power level. Table 1 describes the technical differences between the two
variants.
Table 1 BASIK MIKRO output specifications
Configuration ID Koheras modules are defined by their configuration ID which includes the
options. Refer to Appendix F for a list of Koheras BASIK MIKRO configuration IDs.
Center wavelength The center wavelength of a standard BASIK MIKRO laser is set to 1550.12 nm (ITU
DWDM C-BAND Channel 34). On ordering, the lasers can also be modified at the
factory to other center wavelengths from 1535 to 1580 nm.
Tuning types Both module variants can be further specified with different tuning options. The
options include narrow and wide thermal tuning for coarse adjustment and Piezo
tuning for finer adjustment. The tuning options must be specified when the laser
is ordered from the factory.
Piezo tuning
The standard Piezo tuning option allows the laser to implement fine fast
wavelength modulation. For further information see “Fast wavelength modulation”
on page 19).
Thermal tuning
Thermal tuning options available are:
• Narrow thermal tuning – provides narrow thermal tuning suitable for
systems where a wide tuning range is not required but vibration immunity is
vital.
• Wide thermal tuning – provides a wider thermal tuning range at the expense
of reduced immunity to vibration and acoustic pickup.
Laser features
Thermal tuning The wavelength of the laser can be controlled using a thermal tuning technique
that changes the temperature of the laser’s fiber. The fiber laser is mounted
under tension on a substrate. When the temperature of the substrate changes,
Module Type Maximum Output Power Phase Noise RIN
C15 10 mW Low Ultra-low
E15 40 mW Ultra-low Low
2

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Laser features
the laser cavity length also changes due to thermal contraction or expansion.
Further, the temperature of the laser cavity itself also changes such that the laser
wavelength changes in response to both thermo-optic and physical changes in
the optical path length. See “Tuning the wavelength” on page 49.
Fast wavelength
modulation
As an option, the laser includes the capability to use an external signal to
modulate the emission wavelength using a Piezo. Laser modules with this option
can be modulated using an external electrical signal.
Wavelength+/- Signal
The Wavelength+/- signal is the external signal connected to the laser which
modulates the wavelength. As this signal varies and increases its positive
potential, the wavelength increases. Figure 2 shows the frequency response
when the fast wavelength modulation feature is utilized. The graph shows the
response for both standard and wide thermal tuning substrates.
Figure 2 Frequency response using wavelength modulation
The response shown in Figure 2 is for a laser with a wavelength at 1550 nm. The
response is scaled linearly with the wavelength of the laser.
Further in Figure 2, the Narrow Thermal Tuning module which has less vibration
sensitivity, shows resonances that are higher in frequency. These modules are
therefore more suitable for applications where modulations between 30 and 45
kHz are required.
Note: The frequency response is relatively flat up to 20 kHz, but resonances are
seen at frequencies at and above the first resonance occurring at approximately
30 kHz. Wavelength modulation can be used for frequencies above 20 kHz, but it
is recommended to avoid modulating the laser at the resonance frequencies.
Operating mode The lasers can operate using either current or power mode. Each mode
describes how the emission level of the laser is regulated:
• Current mode – the current in the pump feeding the fiber laser is held stable.
Wide thermal tuning
Narrow thermal tuning

Laser features
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• Power mode – the power out of the fiber laser is held at a fixed level.
The mode set depends on both the model and the application, refer to Table 2 for
the recommended mode to use. See “Setting the operating mode” on page 50.
Table 2 Recommended Power Modes
Note: Modules are configured from the factory to operate in Power mode.
Auto-start The laser includes an Auto-start control bit, when the bit is set, laser emission is
enabled immediately after power is connected. This mode can be useful for
applications where no communication with the module is possible. See “Auto
start” on page 50.
Emission delay The laser has an Emission Delay register which is set to 1.5 seconds by default.
When emission is enabled, the emission LED on the front of the module and the
emission output pin of the electrical interface will immediately indicate emission.
However with this feature, the emission of actual laser light is delayed by the
time set with the register. See “Setting the emission delay” on page 51.
Shutdown delay This feature delays disabling laser emission by 100 ms after the interlock/enable
pins (See “Main electrical interface” on page 24) are set to low or a disable
command is sent. When the laser is integrated with an amplified system, the
shutdown delay ensures the laser’s seed signal does not disappear before an
interfacing amplifier is turned off.
High temperature
shutdown
To prevent thermal run-away when the laser module temperature exceeds 65 °C,
the emission is automatically turned off. The high temperature shutdown feature
uses the thermal control function inside the laser to turn off the emission.
Note: The laser remains ON and has communications enabled, only the emission
is turned off by the feature.
Auto-Start
If after the high temperature shutdown feature turns off emission, the module
temperature drops below 60 °C, laser emission is automatically re-initiated. This
only occurs if laser emission was on before the high temperature shut down and
auto-start is enabled.
BASIK MIKRO
Model
Power Mode Current Mode
C15 Better Power Stability Better Frequency Stability
E15 Better Performance Not Recommended