Bartosz J. Bortnik

Electrooptic Polymer Ring Resonator Modulation up to 165 GHz

Modulation is demonstrated at 84, 111, 139, and 165 GHz resonances of a traveling-wave electrooptic polymer ring-resonator-based modulator. The modulation response is characterized throughout the W-band, illustrating the resonant response at 84 and 111 GHz. A traveling-wave analysis that includes the compound effect of microwave loss and optical/microwave velocity mismatch in a ring-resonator-based modulator is presented and shows a good agreement with experimental results. The ring modulator shows superior performance compared to the Mach-Zehnder modulator in the presence of these limitations when both structures have the same equivalent low-frequency Vpi

Predistortion technique for RF-photonic generation of high-power ultrawideband arbitrary waveforms

By employing an RF-photonic arbitrary waveform generator, the authors experimentally obtained complex high-power RF waveforms with spectra spanning more than a decade and voltage amplitudes of more than 13 V in a system limited by a gain ripple of up to 5 dB and phase distortion of over 200/spl deg/. A spectral predistortion technique tailored to photonically assisted waveform generators that can overcome substantial RF amplifier gain ripple and phase distortion in order to generate high-power (> 30 dBm) ultrawideband arbitrary RF waveforms is presented.

Side-chain electro-optic polymer modulator with wide thermal stability ranging from −46°Cto95°C for fiber-optic gyroscope applications

Electro-optic (EO) polymer modulators with a wide range of thermal stability from −46°Cto95°C for fiber-optic gyroscope applications are reported. The synthesized EO side-chain polymer used has a glass transient temperature (Tg) of 200°C and a large EO coefficient of 25.2pm∕V in a real device measurement. Mach–Zehnder (MZ) intensity and optical phase modulators are implemented based on this high-Tg side-chain EO polymer, exhibiting ∼3.75V half-wave voltage with 1.5cm interaction length and 2.3cm total length at 1.55μm wavelength. The optical fiber-to-lens insertion loss is ∼7.5dB in the MZ interferometers and ∼6dB in the straight waveguides. We examine the long-term thermal stability of these devices and demonstrate their ability to meet the strict requirements of various EO device applications, particularly fiber-optic gyroscopes.

Serrodyne frequency translation of continuous optical signals using ultrawide-band electrical sawtooth waveforms

Serrodyne frequency translation of continuous optical signals by /spl plusmn/1.28 GHz is reported, significantly exceeding the highest previously published serrodyne shifts. To achieve these shifts, an ultrawide-band high-power electrical sawtooth created by spectral modulation of dispersed optical pulses was used. Its amplification involved a novel predistortion technique to compensate for the gain and phase ripple in the amplifier bandwidth.

Electro-optic polymer frequency shifter activated by input optical pulses

We demonstrate electro-optic frequency shifting of 1.55-microm optical pulses by as much as 86 GHz in a polymer traveling-wave phase modulator. The optical pulses were modulated with the linear region of quasi-sinusoidal microwave pulses. In the implemented configuration the electro-optic frequency shifter does not require synchronization with the source of the optical pulses, making it transparent to the optical-pulse repetition rate and increasing its utility. Electro-optic frequency conversion has a number of advantages compared with other methods of all-optical frequency conversion, including no need for a second optical source, high conversion efficiency, and simple control of the output frequency.

High-speed photonically assisted analog-to-digital conversion using a continuous wave multiwavelength source and phase modulation

A more simple photonically assisted analog-to-digital conversion system utilizing a cw multiwavelength source and phase modulation instead of a mode-locked laser is presented. The output of the cw multiwavelength source is launched into a dispersive device (such as a single-mode fiber). This fiber creates a pulse train, where the central wavelength of each pulse corresponds to a spectral line of the optical source. The pulses can then be either dispersed again to perform discrete wavelength time stretching or demultiplexed for continuous time analog-to-digital conversion. We experimentally demonstrate the operation of both time stretched and interleaved systems at 38 GHz. The potential of integrating this type of system on a monolithic chip is discussed.

Suppressed Carrier Optical Transmitter with Intracavity Modulation for Coherent Analog Optical Links

A suppressed carrier optical heterodyne link was demonstrated experimentally with high dynamic range. An efficient laser ring oscillator for heterodyne links is proposed where an intracavity modulator outputs a suppressed carrier signal while recirculating the carrier around the ring.

GHz-range serrodyne frequency shifting of continuous optical signals

Serrodyne frequency shifting of continuous optical signals by /spl plusmn/ 1..28 GHz is reported, exceeding the highest previously published serrodyne shifts by over two orders of magnitude. Electrical sawtooth created by spectral modulation of dispersed optical pulses was used.

Dynamic-Range Enhancement and Linearization in Electrooptically Modulated Coherent Optical Links

We present a general analysis of various electrooptic-modulation configurations on the system performance of a coherent analog optical link. We evaluate the dependence of the modulation scheme of the optical modulator and its properties on the system dynamic range and linearity. Linearization of a coherent optical link based on extending the length of a directional-coupler modulator is also described, illustrating the unique considerations when linearizing a coherent link. System-level modeling of an analog coherent optical link under different modulation configurations is presented.

Ultra-wideband continuous sawtooth generation using RF-photonic technique

We report the first continuous-time implementation of the RF-photonic arbitrary waveform generator. The technique utilizes wavelength-to-time mapping of a broadband optical source to convert spectral modulation into a high fidelity time domain signal. The repetition rate of the system is modified to seamlessly interleave adjacent waveforms. As a proof of concept, an ultra-wideband continuous sawtooth is generated with 260 ps duration and fast 30 ps rise time.