D2-250 Heterodyne Module

D2-250 heterodyne module for creating and collecting an optical beat note between two similar-wavelength cw lasers

As low as $2,320.00


  • Now with kinematic adjustments for fast, easy alignment!
  • Conveniently overlap master & slave lasers to produce optical beat note
  • Large range of power input
  • “Pass-through” beam input configuration
  • Optical beat note delivered to detection module via fiber
  • Works with multimode fiber for easy alignment or single mode fiber for maximum signal
  • Free-space beat note monitor exit for easy alignment
  • Accessory to D2-135 OPLS
  • Also useful with other heterodyne detection schemes

User-adjustable offsets from 250 MHz to >9.5 GHz

D2-250 Heterodyne Module 
The D2-250 Heterodyne Module is designed to conveniently overlap two lasers to produce an optical beat note.  New kinematic adjustment mounts make it easier and faster than ever to co-align master and slave lasers.  The use of rotatable waveplates at the inputs and polarizing beam splitters allows adjustment of pick off a percentage for accepting a large range of powers.

After conversion of the optical beat note to an electrical signal by the D2-260 Beat Note Detector or another fast detector, the electrical signal is delivered to the D2-135 Offset Phase Lock Servo, which compares the divided-down beat note with either an internal or user-supplied reference signal, and locks the slave laser tightly to maintain the desired offset from the master.  The D2-250 is easy to align and only requires a small percentage of the total laser power from the two lasers.

D2-250 Heterodyne Module Specifications
Parameter Value
In-coupling Free-space
Wavelength range 700-1,000 nm
Power range 0.1 mW to 200 mW in each laser
Pick-off percentage 1-98% (variable)
Throughput >98% in each laser; depending on waveplate orientation
Input polarization Linear (horizontal or vertical)
Minimum power in beat note1 >50 μW, optimally 200 μW
Max power at detector1 <1 mW
Fiber connector on module FC/APC2
Compatible fiber type2 Multimode or single mode
All specifications subject to change without notice.
1The maximum power incident upon the detector in the D2-260 Beat Note Detector from the sum total of the master and slave lasers must not exceed 1 mW. Damage to the detector can occur at average powers exceeding 1 mW.
2An FC/APC to LC/PC MM fiber is provided with the D2-260 Beat Note Detector.  (For the D2-160, the cable is FC/APC to SC/PC.)