Push-pull modulated analog photonic link with enhanced sfdr

We demonstrate an analog photonic link (APL) with a high multioctave spurious-free dynamic range (SFDR) of 120 dB.Hz2/3 at the frequency of 2.50 GHz. The APL consists of a pair of distributed-feedback laser diodes (DFB LDs), modulated in a push-pull manner, and a balanced photodetector aiming at suppressing the second-order intermodulation distortion (IMD2). At the frequency of 2.50 GHz, an IMD2 suppression of 40 dB, relative to the case of a single arm APL with one laser, is obtained. In a wide frequency range of 600 MHz (2.60 to 3.20 GHz), an improvement of 5 to 18 dB of the second-order SFDR relative to the single arm APL has been achieved.\ud \u

Enhanced dynamic range in a directly modulated analog photonic link

We demonstrate a directly modulated analog photonic link (APL) capable of a high multioctave spurious-free dynamic range (SFDR). The APL consists of a pair of laser diodes, modulated in a push–pull manner, and a balanced photodetector aiming at suppressing the second-order intermodulation distortion (IMD2). In a wide frequency range of 600 MHz (2.60–3.20 GHz), an IMD2 suppression as high as 23 dB and an improvement of 5–18 dB of the second-order SFDR, relative to a conventional single arm photonic link, have been achieved. In this frequency range, the APL SFDR is in excess of 116 dB.Hz2/3}

Enhancement of multioctave dynamic range in a push-pull modulated analog photonic link

We demonstrate an analog photonic link with a high multioctave spurious-free dynamic range (SFDR) using a push-pull modulation technique of laser diodes combined with a balanced detection scheme. SFDR enhancements ranging from 5 dB to 18 dB, relative to the case of a single arm link, have been obtained in a frequency range of 2.5 GHz to 3.2 GHz

A Novel Modulation Scheme for Noise Reduction in Analog Fiber Optic Links

A novel balanced modulation and detection scheme for analog fiber optic links is proposed to overcome the limitations in signal-to-noise ratio (SNR) and dynamic range (DR). In this scheme, the modulating signal is split into positive and negative halves and applied to a pair of laser diodes. Both arms of the link will convey a half-wave rectified version of the signal. At the receiving end the signal is restored via differential detection. Calculation results show that significant improvement in link SNR together with suppression of second-order distortions are achieved

Interleavers

The chapter describes principles, analysis, design, properties, and implementations of optical frequency (or wavelength) interleavers. The emphasis is on finite impulse response devices based on cascaded Mach-Zehnder-type filter elements with carefully designed coupling ratios, the so-called resonant couplers. Another important class that is discussed is the infinite impulse response type, based on e.g. Fabry-Perot, Gires-Tournois, or ring resonators

Direct experimental observation of pulse temporal behavior in integrated-optical ring-resonator with negative group velocity

We report a direct experimental observation of pulse temporal behavior in an integrated optical two-port ring-resonator circuit as a function of coupling strength, including the transition across the critical coupling point. We demonstrate the observation of pulse ‘advancement’ in the negative v_g regime and pulse delay in the positive v_g regime. We also observed a smooth transition of the pulse shape from highly negative to highly positive v_g (or vice versa) through a pulse splitting phenomenon. The observed phenomena agree well to theoretical simulations

Passband flattened binary-tree structured add-drop multiplexers using sion waveguide technology

When writing this introduction I saw the following press release on the Internet: “Nielsen//Netratings reports a record half billion people worldwide now have home internet access‿. The number of home users grew worldwide with 5 % over the last quarter of 2001. The growth was nearly doubled compared to Q3 2001. The growth in Europe was 4.9%, almost equal to the world growth. One in three households in Europe/Middle East and Africa have Internet access, compared with over half in the US. The Netherlands has 52 % of the households connected to the Internet and 82 % of the computers is connected to the Internet. Another press release also fromNielsen//Netratings was titled as “Broadband Usage Outpaces Narrowband for the first time.‿ 1.19 billion of the total 2.3 billion hours was spent by broadband surfers online in January 2002 in the US. The broadband time spent in January 2002 was 64 % higher than in January 2001. Nearly 21.9 million surfers (in the US) at-home accessed the Internet via broadband connection in January 2002 compared to 13.1 million in January 2001, a boost of 67% in one year time. So there is an unstoppable march towards broadband. (See www.nielsen-netratings.com) This demand can be fulfilled with the tremendous bandwidth of the optical fiber of 30 THz (1420-1670 nm). It is not possible to directly address this complete band, since the current maximum speed of the electronics and modulators is 40-100 GHZ. Wavelength division multiplexing (WDM) is used to divide the band in multiple sub bands. The spacing between the sub band channels is defined by the ITU grid. Common spacings between channels are 12.5, 25, 50, 100 and 200 GHz. The device that combines these channels onto one fiber is called a Multiplexer (Mux) and the device that does the opposite, spatial separation of frequency channels onto different fibers, is called a demultiplexer (Demux). When Mux and Demux are combined it is possible to select only one (or more) channel to be dropped or added and leaving the remaining channels undisturbed. Such a device is called an Add-drop multiplexer(ADM). Optical transmission systems 3.28 Tbit/s over a few hundred of kilometers[Nielsen 2000] or 2 Tbit/s over almost ten thousand kilometers [Yamada 2002] have already be reported