RESUMEN
In this paper, we analyze the dynamics of optical injection in an external cavity based Fabry-Pérot laser diode (ECFP-LD) for wide tunable microwave signal generation. The ECFP-LD is a specially designed FP-LD that has a self-locked single dominant mode. The injected beam power is varied to analyze the dynamics of optical beam injection on the ECFP-LD. The ECFP-LD shows the interesting behavior of red-shift followed by hopping to another self-injected mode equivalent to FP-LD external and internal cavity modes separation, which provides the fine and coarse tuning of the self-injected mode. The optical beating of the injected beam and the self-injected mode, whether it is the fine red-shifted self-injected mode or the hopped self-injected mode equivalent to the external or internal cavity mode separation, provides a wide tunable range of microwave generation. We obtained fine tuning of 3 GHz for every self-injected mode, and coarse tuning of 15 GHz and 150 GHz, which is equivalent to the free spacing tuning of the external cavity (0.12 nm) and internal FP-LD cavity (1.17 nm), with change in the power of the injected beam. The maximum coarse tuning range is about 3.72 nm, and the corresponding beating frequency tuning range is 330 GHz. Hence, a wide tunable microwave frequency can be obtained by optical beating of the shifted/hopped self-injected mode and the injected beam.
RESUMEN
In this paper, we use optical feedback injection technique to generate tunable microwave, millimeter-wave and submillimeter-wave signals using single-mode Fabry-Pérot laser diode. The beat frequency of the proposed generator ranges from 30.4 GHz to 3.40 THz. The peak power ratio between two resonating modes at the output spectrum of can be less than 0.5 dB by judiciously selecting feedback wavelength. In the stabilization test, the peak fluctuation of photonic signal is as low as 0.19 dB within half hour. Aside from locking regions, where the laser is easily locked by the injection beam, the side-mode suppression ratio is well over 25 dB with the maximum value of 36.6 dB at 30.4 GHz beat frequency. In addition, the minimum beat frequency interval between two adjacent photonic signals is as low as 10 GHz.
RESUMEN
We propose and demonstrate a novel scheme for short pulse controlled all-optical switch using external cavity based single mode Fabry- Pérot laser diode (SMFP-LD). The proposed scheme consists of control unit and switching unit as two essential blocks. The basic principle of the proposed scheme is the optical bistability property of SMFP-LD for the control unit and the suppression of the dominant beam of SMFP-LD with injection locking for the switching unit. We also present the analysis of hysteresis width and rising/falling time with change in wavelength detuning which helps to find the optimum wavelength detuning value and power of light beams at different stages of the proposed scheme that gives wide input dynamic power range, high ON/OFF contrast ratio, and low rising/falling time. Input data of 10 Gb/s Non Return to Zero (NRZ) signal is switched at output ports depending upon the control signal generated by the control unit, which comprises of optical SR latch. Output waveforms, clear eye diagrams with extinction ratio of about 11 dB, rising/falling time of about 30 ps and 40 ps, and bit error rate (BER) are measured to validate proposed scheme. No noise floor is observed at output ports up to BER of 10-(12) and the maximum power penalty recorded is about 1.7 dB at a BER of 10-(9) which shows good performance of the proposed short pulse controlled optical switch using SMFP-LDs.
RESUMEN
We propose a novel idea for the suppression of the dominant mode of the single-mode Fabry-Pérot laser diode (SMFP-LD) to realize all-optical multi-logic functions and a digital adder. The basic principle of the proposed scheme is the power management of input beams to suppress the dominant mode of the SMFP-LD for multi-input injection locking. The proposed principle is explained and implemented to realize all-optical multi-logic functions and a digital adder at an input data rate of 10 Gbps. A clear eye opening with an extinction ratio of about 12 dB and a rising-falling time of less than 40 ps are observed at the outputs. The bit error rate (BER) performance is measured for all logic gates and half adder operation. We found there is no BER floor up to BER of 10(-12) and the maximum power penalty of about 1.2 dB at a BER of 10(-9).
