Birefringent modulator

Fig. 1. Representative device configurations exploiting electrooptic second-order nonlinear optical materials are shown. Schematic representations are given for (a) a Mach-Zehnder interferometer, (b) a birefringent modulator, and (c) a directional coupler. In (b) the optical input to the birefringent modulator is polarized at 45 degrees and excites both transverse electric (TE) and transverse magnetic (TM) modes. The appHed voltage modulates the output polarization. Intensity modulation is achieved using polarizing components at the output.

Compared to the Mach-Zehnder modulator, the modulation efficiency of the birefringent modulator is lower because is 1.5 times higher, ie,... 

Birefringent (BR) LCDs, 15 115 Birefringent modulator, 17 446 Birkeland-Eyde process, 17 291-292... 

Fig. 1 - Three common electro-optic device configurations Top Mach-Zehnder interferometer middle birefringent modulator bottom directional coupler...

Equation (9) defines r33 while Eq. (10) defines r13. For electrically poled polymer materials, it is common to assume that r33=3(n0/ne)4r13 [3]. However, the reader should note that this is not always the case [13,14] and is seldom the case with use of laser-assisted (photochemical) poling [15,16]. Thus, we need only consider Eq. (4) in our further discussion. However, it should be noted that devices such as the birefringent modulator depend on the difference between r33 and r13 so that both components can enter the equation for device performance. 

Although Pockels cells were used as CD modulators almost exclusively in older commercial CD instruments (including older J-20 models), some new approaches, such as the use of an elastooptic modulator, have been described (Breeze and Ke, 1972 Cheng et al, 1976). The new CD spectropolarimeters from JASCO and Jobin Yvon are furnished with piezoelastic or elastooptic birefringence modulators, respectively. 

Fig. 3.11 Electro-optic device configurations, (a) Mach-Zehnder interferometer, (b) birefringent modulator. TM and TE denote transverse magnetic and transverse electric polarization, respectively.

As a consequence of the voltage-controlled destructive interference, the applied electrical signal is transduced onto the optical beam as an amplitude modulation. The birefringent modulator depicted in Eig. 3.11b functions as an electri-cal-to-optical signal transducer. Here, both TM and TE optical modes traverse... 

The three most common basic configurations of polymeric modulators are the Mach-Zehnder interferometer, the birefringent modulator, and the directional cou-... 

Fig. 8. Mach Zehnder interferometer (top), birefringent modulator (middle), and directional coupler (bottom) device configurations are shown.

OFC) S - flow straightener R - resistance plate F - flowmeter P - magnetic drive pump Lwet - wetting length, (b) Schematic illustration of the ellipsometer L - He-Ne laser P - polarizer Q -quarterwave plate BM - birefringence modulator Gg - Brewster angle A - analyser PMT - photomultiplier tube. Reprinted with permission from [7a]. (1997) Elsevier. 

RIKES Raman-induced birefringence Modulation of 0)2, is CW Induced change in 0) polarization for 0) -0)2 = ft>Raman Nonresonant background can be suppressed, no phase matching Limited sensitivity, susceptible to turbulence and birefringence from windows, optics, sample... 

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