Interrogators

Lenterra Optical Interrogators (LOI)

Lenterra Optical Sensor Interrogator (LOI) is a compact, robust, fast measurement unit designed for the high resolution interrogation of optical sensors (Fiber Bragg Grating or Whispering Gallery Mode sensors) in laboratory or industrial environments.

LOI utilizes fast, low noise Distributed Feedback diode laser with narrow linewidth for full spectrum scanning. Adjustable photodiode gains allow for measurement of returned light intensity in a wide dynamic range. LOI is controlled by any standard PC through USB interface. The unit can be used with third party FBG or WGM sensors as well as with Lenterra’s RealShear™ and DFF sensors for measurements of such parameters as wall shear stress, drag force, temperature, strain, viscosity and others.

Depending on configuration, LIR consists of one or two Lenterra’s sensors (Drag Force Flow (DFF) or RealShearTM), an LOI optical interrogator and a host computer with control, measurement and data processing software. The probe placed in a desired location within the processing equipment is connected to the interrogator via fiber-optical cable. To install the probe into an apparatus, an adapter is required.

There are two basic types of LIR configurations that are determined by the type of the interrogator – a one channel LOI-2F and a two channel LOI-4F. There are total of six different configurations of LIR specified below. They are customizable, and could be converted one into another by replacing the sensor. Each configuration includes a rugged laptop pre-installed with measurement and post processing software. The LENFLOW measurement software supports all LIR configurations.

LOI-2F

This basic LOI configuration includes one DFF sensor that can be placed in various places inside the processing equipment, for example next to an agitator blade of a mixer as depicted in the figure. Depending on the flow speed and nature of the material, a DFF sensor with required sensitivity should be selected. A standard or custom adapter can be used, See available adapters here.

LOI-4F

This basic LOI configuration includes one DFF sensor that can be placed in various places inside the processing equipment, for example next to an agitator blade of a mixer as depicted in the figure. Depending on the flow speed and nature of the material, a DFF sensor with required sensitivity should be selected. A standard or custom adapter can be used, See available adapters here.

Specifications

Model LOI-2F LOI-4F
Mechanical, Environmental, Electrical Properties
Length 40 cm (15.5") 47 cm (18.5")
Width 30 cm (11.7″)
Height 10.5 cm (4.2″)
Weight 4.7 kg (10.4 lbs) 6 kg (13.2 lbs)
Voltage requirements 100-240 VAC @ 47-63 Hz
Operating temperature From 0°C to 40 °C
Storage temperature From -10 °C to 50 °C
Optical Properties
Light source DFB diode laser
Central wavelength 1540-1560 nm
Linewidth, FWHM <10 MHz
Scan range:
via laser temperature1 3.7 nm
via laser current1, 2 1.2 nm
Scan rate:
via laser temperature1 0.1 nm/s
via laser current1 from 0.33 nm/s to 650 nm/s
Scan frequency (via laser current)3 from 0.25 Hz to 500 Hz
Wavelength increment1
at 0.25 Hz 0.8 pm
at 10 Hz 0.8 pm
at 100 Hz 0.7 pm 1.6 pm
at 500 Hz 2.9 pm 5.4 pm
FBG spectrum tracking repeatability1,4
at 0.25 Hz 0.5 pm
at 10 Hz 0.3 pm
at 100 Hz 0.2 pm
at 500 Hz 0.4 pm
Number of optical channels 2 4
Connector Duplex LC/PC Two FC/APC
Photodiode amplifier gain 105, 106, 107 V/A
Data Processing Capabilities
Interface USB
Software type LabVIEW based data acquisition and control software
Software capabilities Spectra recording, spectra averaging, spectra tracking, differential spectrum (between channels 1 and 2) tracking, data logger, instrument control