Electrooptic eo phase modulators, such as the fibercoupled version in figure 1, are. Our integrated electrooptic platform breaks the tradeo paradigm of existing active photonic circuits and could. T he electrooptic am plitude m odulator e o a m is a pockels cell type. Here we demonstrate a cmoscompatible broadband traveling wave modulator based on a reversebiased pn junction. The results suggest that it will affect the theoretical values of halfwave voltage and bandwidth as well as the optimized electrodes dimension whether considering the conductor loss or not. Starting at this dc voltage, tune to find the minimum. Osa the effect of conductor loss on halfwave voltage and. Use an electrooptic modulator to modulate a beam of laser light. Electro optical modulator system configuration options conoptics. Electro optical modulator system configuration options.
V pi is called the halfwave voltage and is defined as the voltage required to shift the output phase by. Construct an electrooptic variable retarder amplitude modulator, and measure its half wave voltage. Low voltage electrooptic amplitude and phase modulators from. 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 v.
Drive voltages at or below 1 vpp are desirable for compatibility with cmos processes. In a hybrid slotted waveguide polymer system, the nonlinear polymer provides an appealing method for the electrooptic modulator that modulation can work in the pushpull mode, null dc bias, low v. Conoptics laser modulation systems laser accessories. The applied driving voltage, is often expressed in terms of the half wave driving voltage, driving an eo phase modulator at its half wave voltage generates a phase shift equal to pi. The photograph has been kindly provided by ekspla an important property of a pockels cell is the half wave voltage u. The windows are ar coated for 425 700 nm, 700 nm, or 1064 nm. Set up and operate an acousto optic beam deflector. To compare the advantages of resonant enhancement, we can compare the halfwave voltage, vp, the voltage required to produce a p phase shift.
It features low insertion loss, high modulation bandwidth, high extinction ratio, low halfwave voltage and high damage optical power. Our pockels cells utilize wedged windows to ensure 0 offset and to minimize back reflections. For intensity modulators, the half wave voltage is the voltage required to turn the modulator output from minimum to maximum transmission or viceversa for many applications, the half wave voltage is the voltage the modulator must be fed with and it is therefore a main specification of the device. The half wave rectifier circuit is the simplest form of rectifier circuit that can be used, and although it may not provide the highest level of performance in some aspects, it is nevertheless very widely used. Custom cables will need to be used to connect the hva200 to one of our shear piezos. The calculation demonstrates that in order to switch the transmission of an identity modulator between zero and 100%, one needs to modify the applied voltage just by one halfwave voltage. The requirement that the modulating voltage driving eo amplitude modulators include both 0 v and the maximum or minimum halfwave voltage is limiting. Finally, basic bulk electrooptic modulators are described in the fourth section, modulator devices including some design considerations and performance criteria.
This product is mainly used for electro optical signal conversion in highspeed optical fiber communication systems, the generation of light sidebands, high extinction ratio light pulse generation in quantum. Tom baehrjones has designed a slotted design that achieved 0. The electrooptic amplitude modulator eoam is a pockels cell type modulator consisting of two matched lithium niobate crystals see the diagram to the right packaged in a compact housing with an rf input connector. Measurementbased models of a 40 gbits modulator and its electrical driver for transmitter design article pdf available in iee proceedings circuits devices and systems 1522.
Limited applicability of the constant optical power. Therefore, by applying a voltage across the electrodes of an electrooptic. Thorlabs allinone digital reference transmitters are based on proven lithium niobate linbo3 modulator technology driven by highfidelity rf amplifiers. Rp photonics encyclopedia pockels cells, electrooptic. Applying an ac voltage, typically a sine wave, to the phase modulator produces a timedependent phase shift. The half wave diode rectifier is used in a variety of ways and in a host of different types of circuit. In contrast to lumped electrode con gurations, traveling wave tw structures, in which the optical and radio frequency rf waves are made to travel collinearly, allow lower electrical driving power levels with longer modulator lengths. Pdf measurementbased models of a 40 gbits modulator. What is electrooptic modulator an electrooptic modulator eom is a device which can be used for controlling the power, phase or polarization of a laser beam with an electrical control signal. The electrooptic ef fect is one of several means to impose information on. If vis a sawtooth voltage signal with a period twith dc bias voltage vb, as shown in figure 2, then v is a function of time t and can be expressed as fol lows.
It typically contains one or two pockels cells, and possibly additional optical elements such as polarizers. In pockels type of electrooptic modulators like kdp, linbo 3, etc. Rp photonics encyclopedia intensity modulators, acousto. The simplest type of electro optic modulator is a phase modulator containing only a pockels cell, where an electric field applied to the crystal via electrodes changes the phase delay of a laser beam sent through the crystal. Comparison of traveling wave electrodes in lowdriver high. Eom, electro optic modulator phase retardation without external electric field. A bulk electrooptic amplitude modulator consists of a voltagetunable wave plate followed by a polarizer. The hva200 includes an smatobnc cable for connection. This is the voltage required for inducing a phase change of.
The required halfwave voltage needed to drive the eo modulators. The 3 db electrical bandwidth is 33 ghz, with an 18 db extinction ratio. Electrooptic modulation referred to as eo modulation systems are a critical. It is proportionately smaller at shorter wavelengths, and is much smaller for resonant devices due to the. Accurate models of the machzehnder electrooptic modulator and its electrical driver are fundamental for concurrent design of the two devices, and allow careful optimisation of the overall performance of the transmitter. The kyam series electrooptic intensity modulator utilizes the electrooptical effect of lithium niobate,and pushpull machzehnder interference structure to achieve intensity modulation of optical signals. It can also output one 1010v dc voltage for electrooptic intensity modulator bias voltage adjustment, gain and bias voltage are displayed adjustable. From the measured values, calculate the birefringence as a function of applied voltage. The thorlabs hva200 high voltage amplifier is a preferred driver for our electrooptic eo modulators, as well as our shear piezo chips. Conoptics laser modulation systems laser accessories, laser.
There has been great interest in the silicon platform as a material system for integrated photonics. Our integrated electro optic platform breaks the tradeo paradigm of existing active photonic circuits and could. In the calculating results, the comprehensive characterization of the polymer modulator with 1. Electrooptic intensity modulator electrooptic modulator. Electrooptic periodically poled lithium niobate bragg. Jul 01, 2009 what is electrooptic modulator an electrooptic modulator eom is a device which can be used for controlling the power, phase or polarization of a laser beam with an electrical control signal. The theoretical value of the halfwave voltage of the integrated electrooptic modulator or switching voltage can be calculated using the expression where. The pockels cell is an electrooptic device much like an electrooptic modulator that consists of an electrooptic crystal through which light is transmitted.
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 va. Observe the effect of polarization on the phase modulation. If the input polarization is oriented at 45 to the crystal axes, the applied voltage will produce a variable phase delay between the ordinary and extraordinary field components. The photograph has been kindly provided by ekspla an important property of a pockels cell is the halfwave voltage u. The parameter that quanti es the required driving power is the half wave voltage or v. Proposed approach for driving eo phase modulators thorlabs. Halfwave voltage polymeric electrooptic modulators. The phase modulation is then typically transformed into an intensity modulation by sending the light through a polarizer. Measure the half wave voltage, the extinction ratio, and the modulation frequency. Here a measurementbased 40 gbits model of the two devices is proposed and an implementation using the agilentadvanced design system tool is described. Estimate the half wave voltage for the phase modulator.
A key challenge is the development of a lowpower, low drive voltage, broadband modulator. The electrode is designed to be an extension of the driving transmission line. The type of driver you need depends on which modulator you have and how its. Thus, the modulation of the intensity is a sin2 function. Applying an ac voltage, typically a sine wave, to the.
Electrooptic intensity modulator, containing a pockels cell between two polarizers. The applied driving voltage, is often expressed in terms of the halfwave driving voltage, driving an eo phase modulator at its halfwave voltage generates a phase shift equal to pi. All electrooptic modulators listed in this data sheet are of the transverse field. Maldonado department of electrical engineering the uni y ersity of texas at arlington arlington, texas 1 3.
Half wave diode rectifier circuit electronics notes. The kyam series electro optic intensity modulator utilizes the electro optical effect of lithium niobate,and pushpull machzehnder interference structure to achieve intensity modulation of optical signals. The basic question concerning an electrooptic modulator is the voltage required to produce a given change in transmittance. Longitudinal kdp modulator for this to be used as a phase modulator the light must be polarized along x or y and the phase shift is the halfwave voltage is and the modulation depth is. Pockels cell half wave voltage china manufacturers. As opposed to doping, the electron mobility is not impaired by impurity scattering. Improvement in link perfor mance depends on decreasing the halfwave voltage v, because link. They are designed for highspeed fiber optic test and measurement applications. The polarization of the input beam often has to be aligned with one of the optical axes of the crystal, so that the polarization state is not changed.
Eopm half wave voltage vs wavelength 350 300 250 200 150 100 50 0 400 500 600 700 800 900 1100 halfwave voltage wavelength nm eophase modulator specifications specification description modulator crystal lithium niobate linbo 3 wavelength range c1 600nm to 900nm c2 900nm to 1250nm c3 1250nm to 1650nm. The half wave voltage length product of the highperformance devices is 3. Electrooptic modulators are fast optical amplitude or phase modulators based on. Nov 12, 2019 the optical modulator, a machzehnder type, exhibited a halfwave voltage v. Use an electro optic modulator to modulate a beam of laser light. The hva200 includes an smatobnc cable for connection to our freespace electro optic modulators, a usb 2. New focus offers a broad line of electrooptic modulators and drivers that are. Typically, one would vary the voltage between zero and the halfwave voltage, although in principle one may also vary it between.
The discussion presented in this chapter applies to any electrooptic material, any direction of the applied voltage, and any direction of the wave vector. Modulation bandwidths extending into the gigahertz range are possible with the use of lasercontrolled modulators. And electrooptic modulator is based on a pockels cell, which acts as a phase modulator. Design rules and optimization of electrooptic modulators. Photonic integration based on a ferroelectric thinfilm. The transverse field structure allows reduction of va. The thorlabs hva200 high voltage amplifier is a preferred driver for our electro optic eo modulators, as well as our shear piezo. Here c and d are the lengths along y and z direction of the strip of electrooptic material. It can also output one 1010v dc voltage for electro optic intensity modulator bias voltage adjustment, gain and bias voltage are displayed adjustable. Electrooptic modulators with both kerr and pockel types of nonlinearity have wide applications in optics for modulation, demodulation, harmonic generation of light, parametric oscillation and many others schemes. For amplitude modulation, the transmission is given by v sin ot where v tween the emerging optical components. Phase modulators are particularly useful for the generation of frequency side bands on a laser source. This product is mainly used in microwave photonics, rf optical transmission system, picosecond pulse amplification, fiber delay line and other fields. Leysop, manufacturer and supplier of electrooptic modulators and low voltage pockels cells.
Impact of the bias drift to the transfer charts of the modulator if the mzm module is equipped with monitor photodiode working in radiating mode photocurrent i pd increases as the output optical power p o decreases, it is. The results suggest that it will affect the theoretical values of half wave voltage and bandwidth as well as the optimized electrodes dimension whether considering the conductor loss or not. The presented amplitude modulator with an interaction region length of 2. An electrooptic modulator eom or electrooptic modulator is a device which can be used for controlling the power intensity modulators, phase phase modulators or polarization of light with an electrical control signal. The corresponding transfer chart is depicted by black curve in fig.
A pockels cell based on kd p, which can be used for q switching of solidstate lasers. The effect of conductor loss on halfwave voltage and. Osa ultralow drive voltage silicon travelingwave modulator. Highspeed, fiberoptic, digital reference transmitters. Integrated lithium niobate electrooptic modulators operating. A bulk electrooptic amplitude modulator consists of a voltagetunable wave.
Conoptics manufactures a line of laser accessories for laser modulation systems, driver electronics, beam deflectors, noise reduction and optical isolators. The aperture size and halfwave voltage the voltage required to change the. Apr 20, 2020 we not only will try our best to offer excellent services to every customer, but also are ready to receive any suggestion offered by our customers for pockels cell half wave voltage, pockels cell half wave voltage, pockels cell quarter wave voltage, we are seeking for extensive cooperation with honest customers achieving a new cause of glory with customers and strategic partners. Electrooptic phase modulator electrooptic modulator. The modulation may be imposed on the phase, frequency, amplitude, or polarization of the beam.
In this paper, we theoretically deduce the expressions of half wave voltage and 3db modulation bandwidth in which conductor loss is taken into account. With a voltage gain of 20, the amplifier produces a maximum output voltage of 200 v, a continuous current output of 100 ma, a 1 mhz bandwidth, and low noise. Driver available m250 low voltage electrooptic light modulators em 200a em400a this is a very low voltage adp transverse modulator designed to operate at all wavelengths in the visible and is en. This way we demonstrate for the first time data encoding with an soh electrooptic modulator. The required half wave voltage needed to drive the eo modulators.
In this paper, we theoretically deduce the expressions of halfwave voltage and 3db modulation bandwidth in which conductor loss is taken into account. Measure the halfwave voltage, the extinction ratio, and the modulation frequency. The transverse field structure allows reduction of v. Due to the pushpulloperation the half wave voltage of an amplitude modulator is the half of that of a phase modulator with equal electrode length. 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. The hva200 includes an smatobnc cable for connection to our freespace electrooptic modulators, a usb 2. This is the voltage specified either at dc or at the maximum operating frequency required to achieve a phase shift equal to p 3. Measure the diffraction angle and identify the ao modulator material. The kypm series electro optic phase modulator utilizes the electro optical effect of lithium niobate to achieve phase modulation of optical signals, and uses titanium diffusion or proton exchange process to fabricate optical waveguides, which can achieve dualpolarization or singlepolarization phase modulation.