Thorlabs Inc.
Visit the Mach-Zehnder Type Interferometer page for pricing and availability information

Mach-Zehnder Type Interferometer

  • OCT-Proven Clock for Swept Source Systems
  • Compact Design that Allows Subassembly Integration
  • Several Wavelengths Available

INT-MZI-1300

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OVERVIEW

Item # Wavelength
Rangea
Detector
Type
Free
Spectral Range
Insertion
Lossa
INT-MZI-850 780 - 925 nm Si/PIN 103.3 GHz ± 5% <1.5 dB (Typ.),
3 dB (Max)
INT-MZI-1300 1225 - 1375 nm InGaAs/PIN <0.7 dB (Typ.),
1 dB (Max)
  • For the interferometer

Features

  • For 850 nm or 1300 nm Center Wavelengths
  • Ideal for Swept Source Output Frequency Monitoring
  • Balanced Detection Output
  • Low Insertion Loss: <3 dB
  • Flat Wavelength Response
  • Integrated Signal Detection for Power Monitor and k-Clock Signals
  • Interferometer Power Supply Included

Thorlabs' Mach-Zehnder interferometer clock box subassemblies are designed to be used inside a swept source OCT system with a central wavelength of either 850 nm or 1300 nm. The internal fiber couplers are optimized for flat wavelength responses and coupling losses that have a very low polarization dependence, which make the output signals independent of input polarization changes. The clock box contains two detectors, providing a power monitor signal and a k-clock signal that monitors the output frequency of the swept source. Both outputs have a 200 MHz bandwidth, and the k-clock uses a balanced detection scheme to maximize rejection of common mode noise.

Although originally designed for OCT systems, this clock can also be used for other synchronization applications.
For more details on the clock, please see the Operating Principles Tab.

Note: Custom models are available with a choice of free spectral range and wavelength. Please contact Tech Support for more information.


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SPECS

Item # INT-MZI-850 INT-MZI-1300
Optical Specifications
Interferometer Wavelength Range 780 - 925 nm 1225 - 1375 nm
Free Spectral Range 103.3 GHz ±5% 103.3 GHz ±5%
Fiber Type Nufern 780-HP™ Corning SMF28™
Input/Output Connection FC/APC Pigtail, 50 cm Long
Insertion Lossa <1.5 dB (Typ.), 3 dB (Max) <0.7 dB (Typ.), 1 dB (Max)
Electrical Specifications
Detector Material/Type Si/PIN InGaAs/PIN
Detector Wavelength Range 320 - 1000 nm 800 - 1700 nm
Typical Responsivity (Max) 0.53 A/W 1.0 A/W
MZI Output Bandwidth (3dB) DC - 200 MHz
Conversion Gain Power Monitorb 30 V/W (±25%) 60 V/W (±25%)
Conversion Gain MZI Outputb ±30 V/W (±25%) ±60 V/W (±25%)
Saturation Power 100 mW @ 850 nm 50 mW @ 1300 nm
Maximum Input Power 250 mW (Photodiode Damage Threshold)
Electrical Outputs SMA
Impedance 50 Ω
DC Offset < ±5 mV
Power Supply ±12 V @ 250 mA
(100/120/230 VAC, 50 - 60 Hz, Switchable)
General Specifications
Dimensions 120 mm x 80 mm x 16 mm
  • Includes connector losses of the Input and Output pigtail, measured at the central wavelength
  • Conversion gain measured with respect to the output power using a high impedance load, half value with a 50 Ω impedance.

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OPERATING PRINCIPLES

Operating Principles

Rapidly swept laser sources typically use sinusoidal tuning elements to achieve the very fast optical frequency sweep speeds required for OCT imaging applications. Hence, accurate and reliable re-calibration of the OCT signal is required so that the final data points are equidistant in frequency. The Thorlabs swept source laser features a built-in Mach-Zehnder Interferometer (MZI) with balanced detector output that can be used for just this purpose. A frequency clock is derived from the zero crossings of the MZI interference fringe signal; these zero crossings are equally spaced in optical frequency (k-space). While this clock is intended for OCT applications, it can also be used in other synchronization applications.

MZI data
Figure 1: MZI Clock Signal

The schematic of the system is shown in figure 2 below. An internally fiber network is used to tap 5% of the input light to generate Power Monitor and k-clock signals. The remaining light is transmitted to the Output pigtail. Specially designed couplers are used to achieve a flat wavelength response for both the transmitted and the Power Monitor signal. (see figures 3 and 4 below). Both signals of the MZI are detected by an ultra-low noise amplified balanced photo detector.

Schematic diagram of INT-MZI-1300
Figure 2: Schematic of MZI Series Clock Box

graph of coupling ratio from input to output for INT-MZI-1300
Figure 3: Coupling Ratio for INT-MZI-1300 from Input to Output
graph of coupling ratio from input to power for MZI
Figure 4: Coupling Ratio for INT-MZI-1300 from Input to Power Monitor

Hide Pin Diagrams

PIN DIAGRAMS

Power Monitor Output

SMA Female

SMA Female

0 - 1.8 V (50 Ω) or 0 - 3.6 V (High Z)

Mach-Zehnder Interferometer Output

SMA Female

SMA Female

0 - 1.8 V (50 Ω) or 0 - 3.6 V (High Z)


Hide Part Numbers
Part Number
Description
Price
Availability
INT-MZI-850
850 nm Mach-Zehnder Interferometer Clock Box
$2,198.84
Lead Time
INT-MZI-1300
1300 nm Mach-Zehnder Interferometer Clock Box
$2,198.84
2 Weeks