Rangana Banerjee Chaudhuri

Bio: Rangana Banerjee Chaudhuri is an academic researcher from University of Calcutta. The author has contributed to research in topics: Radio frequency & Mach–Zehnder interferometer. The author has an hindex of 3, co-authored 8 publications receiving 16 citations.

Generation of an optical frequency comb based on two cascaded dual-parallel polarization modulators.

Abstract: Generation of an optical frequency comb (OFC) based on two cascaded dual-parallel polarization modulators (DPPolMs) is proposed for the first time, to the best of our knowledge. The proposed method offers superior spectral flatness and improved side-comb suppression ratio (SCSR), and requires low radio frequency drive voltage compared to two cascaded polarization modulators based on OFC generation found elsewhere in the literature. Detailed investigation is carried out through theory and simulation for 25, 49, 81, and 121 comb lines generated with the proposed two-stage OFC generator. Theoretically obtained parameters are used in the simulation to obtain the desired results. In particular, for 49 lines of OFC generation, 1 dB power fluctuation in amplitude and 16.5 dB SCSR are obtained at a comb frequency spacing of 3.5 GHz, which outperforms any polarization modulator-based OFC generator.

Low phase noise frequency tripled microwave signal generation using external optical modulation

Abstract: A high purity low phase noise frequency tripled microwave signal at 6 GHz is generated by applying a 2-GHz electrical drive signal to a quadrature biased Mach Zehnder intensity modulator (MZM). Frequency tripled signal is found advantageous compared to frequency doubled generation in terms of increased dynamic range of input electrical drive power and bias voltage stability of MZM. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1082–1085, 2016

Mitigation of chromatic dispersion electronically in a coherent optical communication system

Abstract: High speed optical fiber transmission performance is severely degraded due to chromatic dispersion in the fiber. Contrary to conventional dispersion compensation techniques by dispersion compensated fiber, in this work electronic compensation techniques are investigated to mitigate chromatic dispersion in a phase modulated optical coherent detection system. Such electronic compensation techniques add flexibility to the dynamically routed optical networks. Performances of electronic mitigation techniques of chromatic dispersion are compared and their applicability limits are evaluated.

Direct and Externally Modulated Fabry-Perot Laser for THz Bandwidth Frequency Comb Generation

Abstract: We report a direct and externally modulated Fabry-Perot laser based frequency comb of bandwidth ≈1.33 THz and flatness less than 6 dB. The measured RIN of the lines from DC to 15 GHz on an average is about -150 dBc/Hz and the linewidth of about 5 MHz.

Electro-optic frequency combs

Abstract: Frequency combs are optical spectra composed of a set of discrete equally spaced lines. Such spectra can be generated by diverse sources such as mode-locked lasers, resonators, or electro-optic modulators. This last possibility has shown a growing interest in the recent years for its advantageous features in providing high repetition rates, intrinsic mutual coherence, or high power per comb lines. Moreover, applications of electro-optic modulator-based combs have flourished in fundamental physics, spectroscopy, or instrumental calibrations. In this paper, we present the most recent progresses made on frequency combs generated by electro-optic modulators, along with the applications where these combs have shown a particular interest.

Direct and External Intensity Modulation in OFDM RoF Links

Abstract: Radio-over-fiber (RoF) systems comprise light modulation and transmission of millimeter-wave signals over fiber links. The aim of this study is to investigate the performance of external and direct intensity modulation in RoF links and to analyze the drawbacks induced by different components of the optical system. In external modulation, the Mach–Zehnder modulator (MZM) is used, whereas the vertical-cavity surface-emitting laser (VCSEL) is utilized in direct modulation. Both modulation schemes are tested for a vector modulation format, i.e., the quadrature amplitude modulation (QAM), where an orthogonal frequency-division multiplexing (OFDM) scheme is used to generate signal subcarriers. The simulations are carried out with the same values of common global parameters for both schemes of intensity modulation. Although VCSEL is a promising device for future RoF systems, the external modulation shows a more robust performance compared with that of VCSEL when implemented with the OFDM modulation technique.

Power efficient optical frequency comb generation using laser gain switching and dual-drive Mach-Zehnder modulator.

Abstract: We propose and experimentally demonstrate a power efficient dual-stage optical frequency comb using laser gain switching followed by a dual-drive Mach-Zehnder modulator (DD-MZM). The laser is initially gain switched at ∼ 9.5 GHz and the resultant comb is then expanded using a dual-drive Mach-Zehnder modulator driven at ∼ 19 GHz with signal amplitudes below 1.5 V. The setup generates an optical frequency comb, with 12 lines within 3 dB flatness, in a power efficient manner. Theoretical analysis is presented and verified through simulation and experimental results.

Planar triple‐band balance‐shaped slot antenna

Abstract: A novel design of planar balance-shaped slot antenna suitable for triple-band WLAN/WiMAX applications is proposed in this article. It consists of a slotted ground plane, an FR4 substrate, and an L-shaped microstrip feedline. The radiating element of the proposed antenna is composed of a horizontal H-shaped slot and an M-shaped slot, like a balance. The horizontal H-shaped slot mainly contributes to the 2.4- and 3.4-GHz resonant modes while the resonant modes at 5.4 and 5.8 GHz are generated by the M-shaped slot. The overall size of the proposed antenna is only 30 × 28 mm2, very compact, making it easy to be integrated with other RF front-end circuits. The measured results agree well with the simulated ones and demonstrate that the antenna has a triple-band characteristic entirely covering the 2.4/5.2/5.8-GHz WLAN and 2.5/3.5/5.5-GHz WiMAX operating bands. Furthermore, monopole-like radiation patterns with acceptable gains make it a good candidate as an internal antenna for WLAN/WiMAX applications. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1078–1082, 2016

Photonic generation of millimeter-wave signal through frequency 12-tupling using two cascaded dual-parallel polarization modulators

Abstract: In this paper, filterless photonic generation of millimeter-wave (mm-wave) signal through frequency 12-tupling via two cascaded dual-parallel polarization modulators (DP-PolMs) is proposed. The principle of operation of the proposed system is theoretically analysed and verified by computer simulation. From the theoretical analysis, the frequency 12-tupling mm-wave signal is shown to be generated by properly adjusting the modulation indices of PolMs, polarization directions of the modulated optical signals, and the phases of the RF drive signals applied to the DP-PolM. The simulation results show that the generated frequency 12-tupling optical mm-wave has high purity with an optical sideband suppression ratio (OSSR) of 25.1 dB and radio frequency spurious suppression ratio (RFSSR) of 19.1 dB. Theoretically obtained results are in good agreement with the simulation results. Furthermore, taking into consideration the practical implementation, the influence of non-ideal parameters on the OSSR and RFSSR are analyzed.