3.5. SuperlumBS

Summary:

Plugin for Superlum BraodSweeper BS-840-1-HP, BS-840-2-HP, BS-1060-1-HP, BS-1060-2-HP.

Type:

DataIO

License:

licensed under LGPL

Platforms:

Windows, (Linux possible but yet not implemented)

Devices:

Lightsource from company SuperlumBS

Author:

J. Krauter, ITO, University Stuttgart

3.5.1. Overview

The SuperlumBS is an itom-plugin, which can be used to communicate with a Superlum BroadSweeper. Different BroadSweeper types (BS-840-1-HP, BS-840-2-HP, BS-1060-1-HP, BS-1060-2-HP) are implemented. Only BS-840-1-HP is tested. The company website can be found under http://www.superlumdiodes.com This system needs a serial port, which differs depending on the controller type. The parameters of the serial port (besides port number) are set automatically during initialization.

It is initialized by dataIO(“SuperlumBS”, SerialIO).

Applications:

  • biomedical imaging

  • optical coherence tomography

  • spectroscopy

  • optical metrology

Features:

  • 3-mW output power ex fiber.

  • Tuning/sweeping range adjustable up to 50 nm.

  • Instantaneous linewidth of less than 0.05 nm.

  • 200 Hz sweep rate over 50 nm.

  • 2 kHz sweep rate over 5 nm.

  • 1 kHz wavelength alternation rate for any two selected wavelengths within full tuning range.

  • PM- or SM-fiber output.

  • Powered directly from a wall outlet.

  • RS-232 remote control capability.

Description:

Broadsweeper BS840 is a widely tunable external cavity laser based on a broadband SOA in a 840-nm band. Fast and narrow-band Acousto-Optic Tunable Filter (AOTF) isused as a selective intracavity element for tuning and sweeping the laser wavelength. Active temperature control of AOTF ensures excellent stability of the wavelength. The absence of moving parts in external cavity ensures high accuracy of wavelength setting and excellent sweep-to-sweep reproducibility of an instantaneous wavelength. A specially designed power control loop allows the Broadsweeper to demonstrate a flat-top tuning characteristic even at the maximum tuning rate. The following modes of operation are available for the standard version: - Operation at any selected wavelength within the full tuning range. - Alternation of the two desired wavelengths (any two wavelengths from the full tuning range may be chosen). - Linear sweep of wavelength with a rate of 200 Hz overthe full tuning range (50 nm), and of 2 kHz over any 5-nm interval within the full tuning range. Broadsweeper’s external cavity is based on a PM-fiber. The standard version is shipped with FC/APC-terminated SM-fiber cable for connection to the optical adapter on the front panel. Output power is measured at the end of this cable. PM-PANDA-fiber cable with main polarization aligned to the key of the connector is optionally available upon request.

3.5.2. Initialization

The following parameters are mandatory or optional for initializing an instance of this plugin:

  • serial: Union[itom.dataIO, itom.actuator]

    An opened serial port (the right communcation parameters will be set by this Superlum BroadSweeper).

    Only plugin “SerialIO” is allowed

  • deviceName: str, optional

    Device name of the Superlum BroadSweeper [BS-840-1-HP].

    Match: “BS-840-1-HP”, Default: “BS-840-1-HP”

To communicate with the device, you need to perform the following settings for the serial port communication using the Plugin SerialIO.

The parameter are as follow:

Baud rate (bits per second)

57600

Data bits

8

Parity

none

Stop bits

1

Flow control

none

Data type

ASCII string

Then create a new instance of the plugin SuperlumBS using the instance of the SerialIO plugin.

serial = dataIO("SerialIO", COM-Port, Baudrate, endline="\r\n")
bs = DataIO("SuperlumBS", serial)

After the initialization of the plugin SuperlumBS the remote communication is set. The plugin works only, if the remote access is available, Master-Key is in position I and the remote Interlock is closed. If the instance of SuperlumBS is deleted, the remote access is switched to the local mode.

3.5.3. Parameters

These parameters are available and can be used to configure the SuperlumBS instance. Many of them are directly initialized by the parameters of the constructor. During the runtime of an instance, the value of these parameters is obtained by the method getParam, writeable parameters can be changed using setParam.

comPort: {int}, read-only

The current com-port ID of this specific device. -1 means undefined.

full_tuning_range_HIGH_end: {float}, read-only

FULL spectral tuning range of sweeping in AUTOmatic OR EXTernal sweep mode in LOW power mode.

full_tuning_range_HIGH_start: {float}, read-only

FULL spectral tuning range of sweeping in AUTOmatic OR EXTernal sweep mode in HIGH power mode.

full_tuning_range_LOW_end: {float}, read-only

FULL spectral tuning range of sweeping in AUTOmatic OR EXTernal sweep mode in LOW power mode.

full_tuning_range_LOW_start: {float}, read-only

FULL spectral tuning range of sweeping in AUTOmatic OR EXTernal sweep mode in HIGH power mode.

local: {int}

( 0 ) local or ( 1 ) remote mode.

master_key: {int}, read-only

Master Key is in position O (0) or position I (1).

modification_end_wavelength: {float}

end modification wavelength in AUTOmatic or EXTernal sweep mode.

modification_start_wavelength: {float}

start modification wavelength in AUTOmatic or EXTernal sweep mode.

modulation_frequency: {float}

Modulation frequency in Two-Wavelength MODulation mode.

name: {str}, read-only

Name of plugin.

operation_booster: {int}, read-only

( -1 ) booster module is not installed, ( 0 ) optical output of booster is disabled, ( 1 ) optical output of booster is enabled.

operation_mode: {int}

( 1 ) MANual, ( 2 ) AUTOmatic, ( 3 ) EXTernal, ( 4 ) MODulation.

optical_output: {int}

( 0 ) optical output is disabeld, ( 1 ) optical output is enabled.

power_mode: {int}

( 0 ) LOW Power mode, ( 1 ) HIGH Power mode.

remote_interlock: {int}, read-only

Remote Interlock is in open (0) or is closed (1).

serial_number: {str}, read-only

Serial number of device.

sweep_speed: {int}

sweep speed in AUTOmatic or EXTernal mode between 2nm/s - 10000nm/s. Increment: 1nm/s.

wavelength: {float}

operation wavelength [nm] in MANual Mode. Increment: 0.05nm.

wavelength_first: {float}

first wavelength in Two-Wavelength MODulation mode.

wavelength_second: {float}

second wavelength in Two-Wavelength MODulation mode.

3.5.4. Usage

First open the serial port and assign it to the variable serial. For example COM Port 1, Baud rate 57600, endline = “\r\n”.

serial = dataIO("SerialIO", 1, 57600, endline="\r\n")

Then create a new instance of the acuator plugin SuperlumBS. A Mandatory parameter is the serialIO instance. Assign it to the variable bs.

bs = DataIO("SuperlumBS", serial)

All the parameter can be changed by using the function setParam. This example shows how the wavelength in the MANual Mode can be changed.

bs.setParam("wavelength", 850.00)

The light of the Broadsweeper is enabled by setting the parameter optical_output to 1 or disabled by setting it to 0.

bs.setParam("optical_output", 1)

The parameters can be queried by using the function getParam. This example shows how to get the Operation Mode of the BroadSweeper device. The return integer value will be 1 for MANual, 2 for AUTOmatic, 3 for EXTneral and 4 for MODulation Mode.

>>bs.getParam("operation_mode")
1
>>

3.5.5. Changelog

  • plugin type changed to dataIO