Optical frequency ab f2 c electro optic modulation z transmission z f. Different techniques to achieve signal coupling and for analyzing the device. Fast electrooptic wavelength selection and frequency. Algebraic approach to electrooptic modulation of light. Pdf frequency modulation response of a liquid crystal. Jaramillovillegas,1,3 poolad imany, 1carsten langrock, 4martin m. This effect is most dramatic when the crystal is driven at a frequency that coincides with an acoustic resonance. Monolithic lithium niobate photonic circuits for kerr. For example, it could not be used to generate a constant change of optical frequency of an optical signal, since that would imply a linearly increasing phase delay without any limit to the phase.
The photonic local oscillator signal generated by electrooptic phase modulation is controlled to track the frequency of the radio frequency rf signal to signi. An important practical limitation to the sensitivity of frequencymodulation spectroscopy arises because of imperfect phase modulation of the laser beam. Sandoval in partial ful llment of the requirements for the degree of doctor of philosophy august 2019. We have fabricated a twist nematic liquid crystal tn cell doped with guanine oligonucleotide g10b and measured its voltagedependent transmittance vt response. This means that the material changes its optical properties when there is an electric field. The optical power of a ld is a function of the injection current, and thus a convenient way to convert an electrical signal into an optical signal is through the direct modulation of the injection current. Acoustooptic modulation of photonic bound state in the. The basic idea behind electrooptic devices is to alter the optical properties of a. An electrooptic modulator eom is an optical device in which a signalcontrolled element exhibiting an electro optic effect is used to modulate a beam of light. In this letter, we propose a straightforward and efficient method for electrooptic frequency comb generation with a small line spacing and a large span. Here, we demonstrate electrooptic modulation of midir absorption in fewlayer black phosphorus. High q photonic resonators and electrooptic coupling. Pdf an important practical limitation to the sensitivity of frequencymodulation spectroscopy arises because of imperfect phase modulation of the. Quantum model for electrooptical amplitude modulation arxiv.
This imperfection manifests itself as residual amplitude modulation ram, and we present data from a careful series of experiments designed to elucidate its origin. Sandoval in partial ful llment of the requirements for the degree of doctor of philosophy august 2019 purdue university west lafayette, indiana. A tutorial introduction to optical modulation techniques by gary breed editorial director t his article introduces the subject of optical modulation, the process of applying information to a light wave. Integrated lithium niobate electrooptic modulators. Disk recordersvideodisk mastering has been entirely dominated by electro optic systems. Pdf residual amplitude modulation in laser electrooptic phase. Weiner1,a 1school of electrical and computer engineering and purdue quantum center, purdue university, west lafayette, indiana. Polymer electrooptic materials have the necessary properties to function in photonic. To within the accuracy of the spcm, this allows shaping of both the amplitude and phase of the antistokes photon. An electrooptic frequency comb enables frequencyagile combbased spectroscopy without using sophisticated phaselocking electronics. Electrooptic modulator, phase modulation, laser frequency stabilization techniques, residual amplitude modulation, lithium niobate crystal, nonlinear.
Optical frequency ab f2 c electrooptic modulation z transmission z f. An appropriate choice of polymers is shown to effectively eliminate the. Ybranch electrooptic amplitude modulator with two sinusoidal modulating. Residual amplitude modulation in laser electrooptic phase modulation article pdf available in journal of the optical society of america b 28. Because the spectral line spacing is set by the electrical oscillator used to drive the phase modulators as opposed to an optical resonator. A tutorial introduction to optical modulation techniques. Experimentally, we find two components to the ram, one that depends for its. A stokes photon detected by an spcm sets the time origin for shaping the antistokes photon with an electrooptic modulator. Midinfrared electrooptic modulation in fewlayer black. Before the advent of the modelocked frequency comb 2, 3, the electrooptic modulation method was a popular technique for measuring frequency differences between lasers. At low frequencies, one part of the total measured response results from a refractive index change produced by the applied electric field. Applied physics express letters open access related. One example is then when there is no electricity, light can pass through, and when there is.
Investigation of the intensity dependence of amplitude noise. An electrooptic modulator eom is an optical device in which a signalcontrolled element exhibiting an electrooptic effect is used to modulate a beam of light. Bias controller of machzehnder modulator for electrooptic. Interferometer criteria for waveguide or fiber optic based interferometer. Application of electrooptic phase modulator in pound. Investigation and cancellation of residual amplitude modulation in fiber electrooptic modulator based frequency modulation gas sensing technique. For some applications, a purely sinusoidal modulation with constant frequency is required.
Conclusions we have demonstrated a frequency offset estimator using electrooptic processing for optical ofdm systems, with the potential to be generalized for coherent optical communication systems. Electrooptic modulator simple english wikipedia, the. In that case, it is often beneficial to use an electrically not mechanically resonant electrooptic modulator, containing a resonant lc circuit. Electrooptic phase modulation, frequency comb generation, nonlinear spectral broadening, and applications a dissertation submitted to the faculty of purdue university by oscar e. The modulation may be imposed on the phase, frequency, amplitude, or polarization of the beam. Electrooptic frequency offset estimator for optical ofdm. The polarization change measured by such techniques is linearly dependent on the electric. This combination delivers high power density and 7ns rise and falltimes. The input voltage of the device can then be substantially lower than the voltage across the electrodes of the pockels cell. The basic idea behind electro optic devices is to alter the optical properties of a. Quantum modelling of electrooptic modulators arxiv. Apes external electrooptic modulator eom is an accessory for laser sources based on apes long standing experience in designing optoelectronics. Modulation bandwidths extending into the gigahertz range are possible with the use of lasercontrolled modulators.
Broadband electrooptic frequency comb generation in a. Osa residual amplitude modulation in laser electrooptic. According to this approach, phase modulation of laser radiation results from the interaction of cavity eigenmodes caused by time periodic modulation of the dielectric constant of the nonlinear crystal placed in the resonator. The modulation may be imposed on the phase, frequency, amplitude. Electrooptic modulation eom is an essentially important optical manipulation for onchip photonics, optical communication and optical sensing. Frequency modulation of probe laser using electrooptic. The strong electrooptic pockels effect in ln leads to a linear change of its refractive index in response to an applied voltage, on. Investigation of the intensity dependence of amplitude. A microphotonic mmwave modulator using simultaneous rf and optical resonance in an electrooptic medium is presented. Note that an electro optic modulator is not suitable for frequency modulation, or precisely speaking only for limited shortterm frequency changes. Electrooptic modulator, phase modulation, laser frequency stabilization techniques, residual amplitude modulation, lithium niobate crystal, nonlinear optical effects, linear electrooptic effect, photorefractive effect, photothermal effect, photorefractive erasure, beam fanning, laser beam shaping, spatial light. Our experimental and theoretical results find that, within the doping range obtainable in our samples, the quantum confined franzkeldysh effect is the dominant mechanism of electrooptic modulation. It is a dedicated modulator that was designed to be used in stimulated raman scattering srs and other applications that.
A continuouswave laser is coupled into the resonator and an optical frequency comb is generated at the output. Acoustooptic modulators can perform other tasks in modulating the laser beam in addition to. Highq microphotonic electrooptic modulator sciencedirect. Theory and simulation of modulator operation is discussed, and experimental results demonstrating modulation using simultaneous resonance in the mmwave range are reported. Applying a voltage across the electrodes of an electrooptic crystal changes the effective refractive index and thus the phase of light as it passes through the crystal. Electrooptic modulation is an important functionality in an optical transmitter, which translates electrical signals into the optical domain. Pdf broadband modulation of light by using an electrooptic.
Pdf investigation and cancellation of residual amplitude. It is found that the operating voltage of a tn cell doped with g10b is higher than. Broadband modulation of light by using an electrooptic. Polymer electrooptic materials have the necessary properties to function in photonic devices beyond the 40ghz bandwidth currently available. Osa dense electrooptic frequency comb generated by two. Meanwhile, the intensity of the laser was also modulated with an electro optic modulator to generate sidebands, producing a frequency tone at.
Our amplitude modulators span the frequency range from dc to 250 mhz while our phase modulators span an impressive frequency. Pdf residual amplitude modulation in laser electrooptic. Because all electrooptic crystals are also piezoelectric, sometimes phase modulation can be accompanied by unwanted amplitude modulation and beam deflection. Nevertheless, dense electrooptic frequency combs over broad spans have yet to be developed. It is made of a material that has a socalled electrooptical effect. Rp photonics encyclopedia electrooptic modulators, eom. Apl photonics 2, 011 2016 highspeed switching of biphoton delays through electrooptic pump frequency modulation ogaga d. Those light waves may be sent through a transparent medium as a laser beam, or contained within a fiber optic cable. The material properties of ln are well suited for realizing ultrafast modulation, lowvoltage operation and low optical losses at the same time. Electro optic phase modulation, frequency comb generation, nonlinear spectral broadening, and applications a dissertation submitted to the faculty of purdue university by oscar e.1033 982 1057 506 1257 829 123 1541 995 595 808 1014 395 1482 944 751 906 1070 1295 397 838 71 1194 371 1480 1227 381 1392 166 767 1171 120 852 1429 1476 493 573 624 528 1270 532 488 93 723 42 268 1086