Conoptics manufactures a line of laser accessories for laser modulation, driver electronics, beam deflectors, noise reduction and optical isolators. All electro-optic modulators listed in this data sheet are of the transverse field type, that is, the electric field produced by the applied signal voltage is perpendicular to the optical propagation direction. The voltage swing required by a given modulator at a given operating wavelength to transit between the full off state to the full on state is called the Half Wave Voltage (V½).

Electro-Optic Modulators

All electro-optic modulators listed in this data sheet are of the transverse field type, that is, the electric field produced by the applied signal voltage is perpendicular to the optical propagation direction. The voltage swing required by a given modulator at a given operating wavelength to transit between the full off state to the full on state is called the Half Wave Voltage (V½). The transverse field structure allows reduction of V½ by manipulation of the crystal length to aperture ratio to a level achievable by available driver electronics. V½ is roughly proportional to wavelength and long wavelength devices usually require higher length to aperture ratios to accommodate existing driver output levels. Conoptics offers modulators constructed with three different crystal species: Ammonium Dihydrogen Phosphate (ADP), Potassium Dideuterium Phosphate (KD*P), and Lithium Tantalate (LTA). Models 370, 380, and 390 utilize ADP as the active element. The unique feature of these models is the virtual non-existence of piezoelectric resonances. Models belonging to the 360 series utilize LTA. LTA has the lowest intrinsic V½ and the longest wavelength IR cutoff.

Furthermore, it has a combination of high refractive index and relatively low dielectric constant which allows modulators to be designed which make full use of the intrinsic driver frequency response. Models in the 360 series exhibit piezoelectric resonances but they are discrete and very narrow. KD*P is used in Model 350 series modulators. In terms of optical transmission bandwidth and driver frequency response utilization, this series falls in between ADP and LTA versions. Table 1 below provides the specifications our ADP (240-to-800nm), KD*P (240-to-1100nm) and LTA (700-2000nm) series modulator product line.

 

ADP Crystal Series Wavelength Limits (240 to 800 nm)*

Model Number V½ wave @ 500nm V½ wave @ 830nm Aperture Diameter Resonances Contrast Ratio @ 633nm Length w/ Polarizer
M370 184 306 2.5mm No 500:1 158mm
M370 LA 263 437 3.5mm No 500:1 158mm
M380 92 153 2.5mm No 500:1 253mm
M390 115 190 3.5mm No 500:1 272mm

KD*P Crystal Series Wavelength Limits (240 to 1100nm)*

Model Number V½ wave @ 500nm V½ wave @ 830nm V½ wave @ 1064nm Aperture Diameter Resonances Contrast Ratio @ 633nm & 1064nm Length w/ Polarizer
M350-50 455 757 970 3.1mm Yes 500:1,700:1 106mm
M350-80 261 433 522 2.7mm Yes 500:1,700:1 137mm
M350-80LA 360 600 720 3.5mm Yes 500:1,700:1 137mm
M350-105 226 376 472 3.1mm Yes 500:1,700:1 162mm
M350-160 130 216 275 2.7mm yes 300:1,500:1 215mm
M350-210 113 188 240 3.1mm Yes 300:1,500:1 268mm

LTA Crystal Series Wavelength Limits (700 to 2000nm)

Model Number

V½ wave @ 830nm V½ wave @ 1064nm V½ wave @ 2500nm Aperture Diameter Resonances Contrast Ratio @ 1064nm Length w/ Polarizer
M360-40 312 400 950 2.7mm Yes 200:1 95mm
M360-80 143 183 430 2.7mm Yes 100:1 137mm
M360-120 107 138 323 2.7mm Yes 100:1 174mm
M360-160 71 92 215 2.7mm Yes 100:1 215mm

Table 2 Amplifier Details

Model Bandwidth Rise/Fall Times Max. Output V Typical Drive Configuration Output
25A DC-to-25MHz 14ns 145 100 Ohms B.L. Linear
25D DC-to-30MHz 8ns 175 100 Ohms B.L. Digital
50 DC-to-50MHz 7ns 90 50 Ohms B.L. Linear
100 DC-to-100MHz 3.5ns 90 50 Ohms B.L. Linear
200 10Khz-to-200MHz 2ns 170 50 Ohms S.E.
275 DC-to-8MHz 50ns 275 Lumped Capacitance Linear
302RM DC-to-250KHz 1 micro-sec 750 Lumped Capacitance Linear
302A DC-to-1MHz 350ns 350 Lumped Capacitance Linear
307 DC-to-50KHz 8ns 800 Lumped Capacitance Digital
505 5MHz-to- 100MHz 3.5ns 44 50 Ohms S.E.
550 20MHz-to- 500MHz 1.5ns 140 50 Ohms S.E.

Special Notes

  • Contrast ratio measured with 1mm beam @ 1% point.
  • Special Order wavelengths below 400nm are available, please contact sales@conoptics.com
  • Special Clamped Version available to minimize piezo-electric resonances
  • To determine the ½ wave voltage at your operating wavelength, compute the voltage listed and multiply by the ratio of the desired wavelength (i.e. M350-50 @ 700nm = 455 x 700nm / 500nm = 637 Volts)
  • The last Digits of the Model Number for the 350 and 360 Series designate the total crystal path length in millimeters.