Gain-clamped Erbium-doped Fiber Amplifier Research Articles

Gain-clamped erbium-doped fiber amplifier using a Sagnac loop and low-reflectivity fiber Bragg grating

Gain-clamped erbium-doped fiber amplifier using a Sagnac loop and low-reflectivity fiber Bragg grating

Stability improvement in a gain-clamped L-band erbium-doped fiber amplifier through hybrid gain control

The stability of gain-clamped erbium-doped fiber amplifiers (EDFAs) may be affected by the parameter drift of active and passive devices. We propose a hybrid gain-control scheme to enhance the working stability, which consists of an optical dual-fiber-Bragg-grating (FBG)-based linear cavity and an electrical fuzzy-based controller. The principle of optical gain clamping is then depicted and a detailed design about dual-channel fuzzy controller is given. The experimental results show that, in the dual-FBG configuration, with 20.2-dB mean gain, the designed L-band EDFA simultaneously guarantees the ±0.1-dB stability (with 30-dB dynamic range) and the ∼0.4-dB flatness in the range of 1570 to 1610 nm. In addition, under the electrical feedback control, the flatness stability of gain spectrum reaches ±0.18 dB within 60 min and the mean gain stability is about ±0.34 dB within 10-h continuous operation.

Gain-Clamped 4-LP-Mode Erbium-Doped Fiber Amplifier With Low Temporal Gain Variation

We demonstrate a ring-resonator-based gain-clamped 4-LP-mode erbium-doped fiber amplifier (EDFA). In this study, we show that a gain-clamped EDFA can reduce temporal modal gain variation simultaneously in all modes. We experimentally evaluate the transient response of a 4-LP-mode EDFA and succeed in reducing the modal gain variation for all modes at 1530 and 1550 nm from 4.0 to 1.1 dB and from 2.8 to 0.7 dB, respectively, by using a gain-clamping technique.

All-optical gain-clamped EDFA using external saturation signal for burst-mode upstream in TWDM-PONs.

While the gain-transient suppression of erbium-doped fiber amplifiers (EDFAs) has been widely studied, the large interval between upstream burst-mode signals from optical network units (ONUs) in time- and wavelength-division multiplexing passive optical networks (TWDM-PONs) presents new challenges. A non-gain-clamped EDFA acting as a preamplifier does not have the desired overshoot on the burst-mode signal when there are only a few ONUs in operation in the TWDM-PON. To solve this problem, we propose an all-optical gain-clamped EDFA (OGC-EDFA) that uses a distributed feedback laser diode to generate a saturation signal. An OGC-EDFA based on a ring laser configuration was also tested to compare the overshoot performance; the both OGC-EDFAs showed negligible overshoot performance. Given the negligible overshoot and wide input dynamic range of the OGC-EDFA, the proposed amplifier is thought to be a simple, low-cost solution for TWDM-PON applications.

Gain clamped L-band EDFA with forward–backward pumping scheme using fiber Bragg grating

The paper proposes a novel two stage L-band erbium doped fiber amplifier with forward–backward pumping scheme for transmission of 32 wavelength division multiplexed (WDM) channels. It is gain clamped with an in-line fiber Bragg grating (FBG) to provide flat gain over 45nm by restricting and reutilizing amplified spontaneous emission (ASE). We demonstrate that it provides an efficient small signal gain with minimum noise figure of over 20dB and 5.5dB, respectively, in the L-band region (1565–1610nm) by comparing with its forward and backward pumped counterparts with fixed Er3+ fiber length of 20m for −30dBm/channel input power. We also obtain the gain and noise figure dependence as a function of each of the Er3+ fiber lengths, pump power (both 1480 and 980nm), and temperature. Hence a 10nm region (1580–1590nm) has been acknowledged where temperature variations become constricted for 30°C variations (15–45°C).

Impact of Burst Size and Inter-Arrival Time in All-Optical Gain Clamping Amplification for Optical Burst Switched Networks

This paper considers an optical burst switching network of 16 WDM channels amplified by all-optical gain clamped erbium-doped fiber amplifier. Experimental and numerical investigations are carried out in order to determine the impact of the burst length and inter-arrival time in the performance of stabilized amplification. The results show that the design of synchronous burst networks should take into account the characteristics of the clamped amplifier, whereas for asynchronous transmission, the power ripples induced by the critical cases may be neglected.

Modeling of Wide-Band Optical Signal Amplification in an EDFA Network Using Tunable Tap

Optical amplification in C and L band region with wave division multiplexing can provide over 160 channels. The paper provides simulation studies of such a wideband erbium doped fiber amplifier which utilizes a tunable tap at the TLS source end. This isolates and provides two parallel channels for simultaneous amplification in both C and L band. Such a configuration has shown to provide a gain well over 20dB from 1525-1615nm bandwidth with average noise figure of 10dB (approx.). Gain saturation effects beyond -20dBm/channel signal level and, gain spectra at different pump powers and amplifier lengths have also been studied. Full Text: PDF References Robert E. Tench, Proc. IEEE Elecronic Componenets and Technology Conference. 9, (1999). J. F. Massicott, R. Wyatt, and B. J. Ainslie, "Low noise operation of Er 3+ doped silica fibre amplifier around 1.6 ?m", Electron. Lett. 28, 1924 (1992). CrossRef Y. Sun, A. Srivastava, J.Zhou, and J. Sulhoff, "Optical fiber amplifiers for WDM optical networks", Bell Labs Technical Journal. 4, (1999) CrossRef H. Ono, M. Yamada and Y. Ohishi, "Gain-flattened Er/sup 3+/-doped fiber amplifier for a WDM signal in the 1.57-1.60-?m wavelength region", IEEE Photon. Technol. Lett. 9, (1997). CrossRef C. Jiang, W. Hu, Q. Zeng and S. Xiao, "High detectivity GaInAs-InP quantum-well infrared photodetectors grown on Si substrates", IEEE Photon. Technol. Lett. 14, 290 (2002). CrossRef M. A. Mahdi, F. R. M. Adikan, P. Poopalan, S. Selvakennedy, W. Y. Chan, and H. Ahmad, "Long-wavelength EDFA gain enhancement through 1550 nm band signal injection", Opt. Commnun.175, 296 (2000). CrossRef H. Chen, M. Leblanc and G.W. Schinn, "Gain enhanced L-band optical fiber amplifiers and tunable fiber lasers with erbium-doped fibers", Opt. Comm. 216, 119 (2003). CrossRef M. A. Mahdi and H. Ahmad, "Gain enhanced L-band Er/sup 3+/-doped fiber amplifier utilizing unwanted backward ASE", IEEE Photon. Technol. Lett. 13, 1067 (2001). CrossRef S. W. Harun, N. Tamchek, P. Poopalan and H. Ahmad, "Gain clamping in two-stage L-band EDFA using a broadband FBG", IEEE Photon. Technol. Lett. 16, 422 (2004). CrossRef T. Sakamoto. "Wide wavelength band (1535?1560 nm and 1574?1600 nm), 28 × 10 Gbit/s WDM transmission over 320 km dispersion-shifted fibre", Electron. Lett.34, 392 (1998). CrossRef Y. Sun et al., "80 nm ultra-wideband erbium-doped silica fibre amplifier", Electron. Lett. 33,1965 (1997). CrossRef T. Kasamatsu, Y. Tano and T. Ono, 13, 31 (2001). S. K. Liaw and Y. K. Chen, "Self-phase modulation coefficient of multiple-quantum-well optical amplifiers", IEEE Photon. Tech. Lett. 8, 876 (1996). CrossRef A. Srivastava and Y. Sun, Optical Fiber Telecommunications, I. P. Kaminov and T. Li, Eds. (San Diego, CA: Academic 2002, vol. VI A). R. Anthony and S.N. Biswas, "Temperature Dependent Gain Analysis of a Cascaded C-Band EDFA DWDM Network", Elseviers Procedia Technol. 4, 92 (2012). CrossRef G. Luo, J. L. Zyskind, I. A. Nagel, and M. A. Ali, "Experimental and theoretical analysis of relaxation-oscillations and spectral hole burning effects in all-optical gain-clamped EDFA's for WDM networks", IEEE J. Lightwave Technol. 16, 527 (1998). CrossRef I.K. Bu Sohn and J.W. Song, "Gain flattened and improved double-pass two-stage EDFA using microbending long-period fiber gratings", Optical Communications. 236, 141 (2004). CrossRef R. Singh, Sunanda and E.K. Sharma, "Gain flattening by long period gratings in erbium doped fibers", Optical Communications. 240, 123 (2004). CrossRef

High Efficiency Automatic-Power-Controlled and Gain-Clamped EDFA for Broadband Passive Optical Networking Systems

The configuration of a simple improved high efficiency automatic-power-controlled and gain-clamped EDFA (APC-GC-EDFA) for broadband passive optical networking systems (BPON) is presented here. In order to compensate the phase and amplitude variation due to the different distance between the optical line terminal (OLT) and optical network units (ONU), the APC-GC-EDFA need to be employed. A single 980 nm laser module is employed as the primary pump. To extend the bandwidth, all C-band ASE is recycled as the secondary pump to enhance the gain efficiency. An electrical feedback circuit is used as a multi-wavelength channel transmitter monitor for the automatic power control to improve the gain-flattened flatness for stable amplification. The experimental results prove that the EDFA system can provide flatter clamped gain in both C-band and L-band configurations. The gain flatness wavelength ranging from 1530 to 1610 nm is within 32.83 ± 0.64 dB, i.e. below 1.95 %. The gains are clamped at 33.85 ± 0.65 dB for the input signal power of −40 dBm to −10 dBm. The range of noise figure is between 6.37 and 6.56, which is slightly lower compared to that of unclamped amplifiers. This will be very useful for measuring the gain flatness of APC-GC-EDFA. Finally, we have also demonstrated the records of the overall simultaneous dynamics measurements for the new system stabilization. The carrier to noise ratio (CNR) is 49.5 to 50.8 dBc which is above the National Television System Committee (NTSC) standard of 43 dBc, and both composite second order (CSO) 69.2 to 71.5 dBc and composite triple beat (CTB) of 69.8 to 72.2 dBc are above 53 dBc. The recorded corresponding rise-time of 1.087 ms indicates that the system does not exhibit any overshoot of gain or ASE variation due to the signal at the beginning of the pulse.

Single-stage gain-clamped L-band EDFA with C-band ASE saturating tone

We demonstrate a single-stage gain-clamped L-band Erbium-doped fiber amplifier with 1480 nm pump wavelength. The gain-clamping technique is achieved by utilizing the backward propagation of C-band amplified spontaneous emission (ASE). This unwanted noise is reflected back into the optical amplifier and its intensity is adjusted using the variable optical attenuator. The C-band ASE sets the population inversion level along the Erbium doped-fiber and limits the L-band signal amplification to a specific value. The whole optical bandwidth in L-band can be employed for signal amplification since the saturating tone is out of the band. The gain dynamic range of 11.7 dB is obtained between 21.7 and 10.0 dB with noise figure of less than 5.5 dB for signal power up to 2 dBm.

L-band automatic-gain-controlled erbium-doped fiber amplifier utilizing C-band backward-amplified spontaneous emission and electrical feedback monitor

A new L-band automatic-gain-controlled (AGC) erbium-doped fiber amplifier (EDFA) for dense wavelength-division-multiplexing transmission systems is presented, in which a single 1480 nm laser with an internal thermoelectric cooler is used as a primary pump for stable amplification. All C-band amplified spontaneous emission (ASE) is recycled by the secondary pump to enhance the gain efficiency. A fraction of the output signal is used as an electrical feedback monitor for the AGC to improve the gain-clamped (GC) flatness. Experimental results prove that the AGC EDFA has a gain flatness of better than 0.46 dB/40 nm, i.e., below 1.5%, and a higher gain of approximately 36.5 dB compared to that of approximately 35.3 dB for the conventional GC EDFA at -30 dBm input signal power. The best gain flatness of +/-0.25 dB can be achieved over the dynamic range greater than 20 dB. The dynamic range of noise figure is between 6.7 and 7.1. The 3 dB down bandwidth is more than 40 nm. Overall dynamics measurements for the AGC EDFA feedback stabilization have been carried out. The recorded corresponding rise time of 1.565 ms indicates that the system does not exhibit any overshoot of gain or ASE variation due to the signal at the beginning of the pulse.

Performance of an Adaptive Threshold Receiver in a Dynamic Optical Burst-Switched Network

We compare the performance of a digital receiver operating with both a fixed and adaptive decision threshold in response to gain transients arising from network operation of an optically gain-clamped erbium-doped fiber amplifier. An optical burst switching link, based on a recirculating transmission loop, is used to study the effect of transients accumulated across a number wavelength-routing nodes linked by amplified fiber spans where bursts are added and dropped at each node. The use of an adaptive threshold reduces the amount of optical feedback required by a factor of 6 and, in some cases, allows for unclamped operation.

All-optical Gain-clamped Erbium-doped Fiber Amplifier with Narrowband Amplified Spontaneous Emission Feedback Technique

All-optical gain clamping of an erbium-doped fiber amplifier (EDFA) based on an unique narrowband amplified spontaneous emission (ASE) feedback technique is demonstrated by incorporating a series of fiber Bragg grating at the output end of the amplifier. The reflected ASE acts as an additional signal to limit the population inversion and clamps the amplifier's gain. The gain of the proposed amplifier is clamped at 26.5 dB with dynamic input signal power up to -14 dBm and gain variation of less than 0.1 dB. The corresponding noise figure is less than 6.9 dB. The absence of any oscillating laser in this technique is advantageous since it can avoid relaxation oscillation effect.

Experimental investigation of optically gain-clamped EDFAs in dynamic optical-burst-switched networks: publisher's note

In [J. Opt. Netw.7, 151 (2008)] the wrong version of Fig. 4 was published and the image appeared identical to that of Fig. 7. The figure has been corrected online as of January 22, 2008.

GC-EDFA for a Burst Packet Mode Optical Switching System

A two-stage gain-clamped erbium doped fiber amplifier (GC-EDFA) using a pump laser diode and a 16 channel wavelength division multiplexing (WDM) with 0.8 nm spacing in C band of $1,545{\sim}1,560nm$ wavelength is experimentally demonstrated for a burst packet mode optical switching system.

Characterization of lasing-oscillation direction in optical gain-clamped erbium-doped fiber amplifiers

In this paper, the effect of ring-laser propagating direction in gain-clamped erbium-doped fiber amplifiers is investigated. The optical amplifier architecture under study is based on ring-laser cavity. The strongest gain-clamping effect is obtained for bi-traveling ring-laser in the optical amplifier. On the other hand, the low-noise figure operation can be achieved by allowing the ring-laser to co-travel with the signal propagation.

Gain-clamped dual-stage L-band EDFA by using backward C-band ASE

A dual-stage L-band gain-clamped erbium-doped fiber amplifier (GC-EDFA) by using backward C-band amplified spontaneous emission (ASE) is proposed. Compared with other similar GC-EDFAs, the proposed structure has higher and flatter clamped gain in L-band because of its optimal pump power and EDF length. The flatness from 1570nm to 1600nm arrives 0.77dB, the bandwidth of 3dB is more than 35nm and the maximal input signal power arrives −15dBm.

Tunable gain-clamped double-pass Erbium-doped fiber amplifier

A tunable, gain-clamped (GC) double-pass Erbium-doped fiber amplifier (EDFA) with a linear laser-cavity configuration has been demonstrated. It solves the problems existing in the conventional linear-cavity GC-EDFA based on two fiber Bragg gratings (FBGs), in which the clamped-gain is very difficult to be tuned. In the new GC-EDFA, the lasing oscillation for clamping the gain is produced in a linear cavity comprised by a FBG and a fiber reflection mirror (FRM). Between them, a filter filters out the lasing light, and then a variable optical attenuator changes the loss of the laser cavity for tuning the clamped-gain. Meanwhile, the double-pass configuration is used to enhance the gain efficiency, and therefore the level of the clamped-gain is greatly improved.

S-band gain-clamped grating-based erbium-doped fiber amplifier by forward optical feedback technique

An S-band gain-clamped erbium-doped fiber amplifier module, employing a fiber Bragg grating to serve as a reflected element for lasing a saturated tone injected into the module by forward optical feedback method, is proposed and investigated experimentally. Moreover, the performance and behavior of the gain and noise figure in the proposed gain-clamped S-band fiber amplifier have also been discussed in the effectively wavelength range of 1478 to 1520 nm.

Transient insensitive all-fibre gain-clamped EDFA based on highly-doped Er:Yb-fibre

A sub-metre-long optically-gain-clamped all-fibre amplifier based on a highly-doped Er-Yb-doped phosphate glass fibre of <10 cm length is demonstrated. Optical gain clamping by means of a very short laser cavity results in high insensitivity to channel power transients with only 4% extra pump power penalty. Exploiting all-fibre technology, such a device is very promising for WDM metro network applications.

All-optical gain-clamped L-band erbium-doped fiber amplifier with two feedback-loop lasing wavelengths

We experimentally investigate an optically gain-clamped (GC) L-band (1570 to 1600 nm) erbium-doped fiber amplifier (EDFA). Two lasing wavelengths in the optical feedback loop, 1568 and 1600 nm, are separately used for gain clamping with different loop attenuations. The characteristics of the EDFA with single-channel and simulated multichannel operations are examined and compared. We find that the 1568-nm lasing light is a better selection for an L-band GC EDFA to offer good channel gain with satisfactory noise figure characteristics.