Electro-optic modulator for high-speed Nd:YAG laser communication

Abstract

An engineering model of an electrooptic intensity modulator for Nd:YAG laser wavelength (1.O6im) was designed, manufactured, and tested under ESA contract in cooperation with the Institut für Nachrichtentechnik und Hochfrequ9ztechnik 1 Technische Universität Wien. Two Lithium Niobate crystals with O.5x0.5x4Omm each were cascaded to constitute a traveling wave electrooptic bulk modulator. The crystals were embedded in a beryllia holding structure to guarantee mechanical alignment and good heat transfer. Electronic bias voltage control was implemented to compensate thermal disturbances and ageing effects. Only materials, parts, and processes compatible with the ESA requirements for operation in space were used. The following performance data were achieved: Optical transmittance > 86%, optical power handling > 1W cw at 1.O6m, electrical bandwidth 1.8GHz, halfwave voltage 39V, extinction ratio 14dB, modulation data rate lGbit/s.

Distinguishing dxz+idyz and dx2−<

“…5 we show the spin susceptibility ratio between the superconducting and the normal states as a function of field for T = 25 mK with the applied magnetic field scaled by the upper critical field. Also shown is the experimental data for the Knight shift obtained by NMR at two different oxygen positions (for O(1) at 66 mK [10] and for O(2) at 25 mK [8]), along [10] and at 25 mK [8] and the PNS data at 60 mK [42] and at 25mK [44]. Note that the applied magnetic field has been divided by the critical field value Hp, which for the case of d with neutron scattering data measured at 60 mK [42] and 25 mK [44].…”

“…Also shown is the experimental data for the Knight shift obtained by NMR at two different oxygen positions (for O(1) at 66 mK [10] and for O(2) at 25 mK [8]), along [10] and at 25 mK [8] and the PNS data at 60 mK [42] and at 25mK [44]. Note that the applied magnetic field has been divided by the critical field value Hp, which for the case of d with neutron scattering data measured at 60 mK [42] and 25 mK [44]. Within the broad scatter of experimental points, it can be seen that both pairing types agree well with the data.…”

“…(Color online)Spin susceptibility ratio as a function of field for temperature value of 25 mK for dxz +idyz (Eg) and d x 2 −y 2 (B1g) pairing. Also presented is experimental data for the Knight shift measured at two different positions of Oxygen atoms at 66 mK[10] and at 25 mK[8] and the PNS data at 60 mK[42] and at 25mK[44]. Note that the applied magnetic field has been divided by the critical field value Hp, which for the case of d x 2 −y 2 is chosen to be the upper critical field Hp2, see the discussion of the H − T phase diagram in Sec.…”