Abstract

Design and fabrication of a tunable gain equalization filter for dense wavelength division multiplexed (DWDM) signals through erbium doped fiber amplifiers (EDFA) is reported. It is based on a side-polished fiber (SPF) half-coupler block loaded with a displaceable tapered multimode overlay waveguide (MMOW). A simple and accurate normal mode analysis is employed to design this filtering device for its subsequent realization. Equalization of a typical EDFA gain spectrum in the C-band within ±0.35 dB or even less in the presence of various ITU standard C-band DWDM signal channels is demonstrated under varied operating conditions like add/drop of signals. Tunability of the filter notch is achieved through displacement of the SPF relative to the MMOW.

© 2007 Optical Society of America

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    [CrossRef]
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2007 (1)

R.K. Varshney, A. Singh, K. Pande, and B.P. Pal, "Side-polished fiber-based gain-flattening filter for erbium doped fiber amplifiers," Opt. Commun. 271, 441- 444 (2007).
[CrossRef]

2005 (4)

K. T. Kim, S. Hwangbo, J. P. Mah, and K. R. Sohn, "Widely tunable filter based on coupling between a side-polished fiber and a tapered planar waveguide," IEEE Photon. Technol. Lett. 17, 142-144 (2005).
[CrossRef]

N. Kumar, M.R. Shenoy, and B.P. Pal, "A standard fiber-based loop mirror as a gain-flattening filter for erbium-doped fiber amplifiers," IEEE Photon. Technol. Lett. 17, 2056-2058 (2005).
[CrossRef]

Y.J. Rao, A.Z. Hu, and Y.C. Niu, "A novel dynamic LPFG gain equalizer written in a bend-insensitive fiber," Opt. Commun. 244, 137 -140 (2005).
[CrossRef]

J.K. Bae, J. Bae, S.H. Kim, N. Park, and S.B. Lee, "Dynamic EDFA gain-flattening filter using two LPFGs with divided coil heaters," IEEE Photon. Technol. Lett. 17, 1226-1228 (2005).
[CrossRef]

2002 (2)

I.B. Sohn, J.G. Baek, N.K. Lee, H.W. Kwon, and J.W. Song, "Gain flattened and improved EDFA using microbending long-period fiber gratings," Electron. Lett. 38, 1324-325 (2002).
[CrossRef]

M. Harumoto, M. Shigehara, and H. Suganuma, "Gain-flattening filter using long-period fiber gratings," IEEE J. Lightwave Technol. 20, 1027-1033 (2002).
[CrossRef]

2001 (1)

S. Li, K. S. Chiang, and W. A. Gambling, "Gain flattening of an erbium doped fiber amplifier using a high-birefringence fiber loop mirror," IEEE Photon. Technol. Lett. 13, 942-944 (2001).
[CrossRef]

2000 (1)

M.K. Pandit, K.S. Chiang, Z.H. Chen, and S.P. Li, "Tunable Long-Period Fiber Gratings for EDFA gain and ASE equalization," Microwave and Opt. Technol. Lett. 25, 181-184 (2000).
[CrossRef]

1999 (2)

Y. Liu, J.A.R. Williams, L. Zhang, and I. Bennion, "Phase shifted and cascaded long-period fiber gratings," Opt. Commun. 164, 27-31 (1999).
[CrossRef]

P.D. Greene and H.N. Rourke, "Tailoring long period optical fiber gratings for flattening EDFA gain spectra," Electron. Lett. 35, 1373-1374 (1999).
[CrossRef]

1998 (4)

J-C. Dung, S. Chi, and S. Wen, "Gain flattening of erbium-doped fiber amplifier using fiber Bragg gratings," Electron. Lett. 34, 555-556 (1998).
[CrossRef]

J.R. Qian and H.F. Chen, "Gain flattening fiber filters using phase shifted long period fiber gratings," Electron. Lett. 34, 1132-1133 (1998).
[CrossRef]

H.S. Kim, S.H. Yun, H. K. Kim, N. Park, and B.Y. Kim, "Actively Gain-flattened erbium-doped fiber amplifier over 35 nm by using all-fiber acousto-optic tunable filters," IEEE Photon. Technol. Lett. 10, 790 -792 (1998).
[CrossRef]

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

1997 (1)

C.R. Giles, "Lightwave applications of fiber Bragg gratings," IEEE J. Lightwave Technol. 15, 1391-1404 (1997).
[CrossRef]

1996 (4)

A. M. Vengsarkar, P. J. Lemaire, J. B. Judkins, V. Bhatia, T. Erdogan, and J. E. Sipe, "Long-period fiber gratings as band-rejection filters," IEEE J. Lightwave Technol. 14, 58-64 (1996).
[CrossRef]

R. D. Pechstedt and P. St. J. Russell, "Narrow-band in-line fiber filter using surface-guided Bloch modes supported by dielectric multilayer stacks," IEEE J. Lightwave Technol. 14, 1541-1545 (1996).
[CrossRef]

B.P. Pal, G. Raizada, and R.K. Varshney, "Modelling a Fiber Half-block with Multimode Overlay Waveguide," J. Opt. Commun. 17, 179-83 (1996).

G. Raizada, B.P. Pal, and R.K. Varshney, "Estimating performance of fiber optic modulators/switches with multimode electro-optic overlay/interlay waveguide," Opt. Fib. Tech. 2, 89-97 (1996).
[CrossRef]

1995 (2)

J. Y. Pan, M. A. Ali, A. F. Elrefaie, and R. E. Wagner, "Multiwavelength fiber-amplifier cascades with equalization employing Mach-Zehnder optical filter," IEEE Photon. Technol. Lett. 7, 1501-1503 (1995).
[CrossRef]

S. Yoshida, S. Kuwano, and K. Iwashita, "Gain-flattened EDFA with high Al concentration for multistage repeatered WDM transmission systems," Electron. Lett. 31, 1765-1767 (1995).
[CrossRef]

1994 (2)

R.B. Charters, A.P. Kuczyhski, S.E. Stakes, R.P. Tatam, and G.J. Ashwell, "In-line fiber optic channel dropping filter using Langmuir-Blodgett films," Electron. Lett. 30, 594-595 (1994).
[CrossRef]

K. McCallion, W. Johnstone, and G. Fawcett, "Tunable fiber optic in-line bandpass filter," Opt. Lett. 19, 542-544 (1994).
[CrossRef] [PubMed]

1993 (2)

D.G. Moodie and W. Johnstone, "Wavelength tunability of components based on the evanescent coupling from a side-polished fiber to a high-index-overlay waveguide," Opt. Lett. 18, 1025 - 1027 (1993).
[CrossRef] [PubMed]

R. Kashyap, R.  Wyatt, and P.F. McKee, "Wavelength flattened saturated erbium amplifier using multiple side-tap Bragg gratings," Electron. Lett. 29, 1025-1026 (1993).
[CrossRef]

1990 (1)

A. Sharma, J. Kompella, and P.K. Mishra, "Analysis of fiber directional couplers and coupler half-blocks using a new simple model for single-mode fibers,"IEEE J. Lightwave Technol. 8, 143-151 (1990).
[CrossRef]

1989 (1)

C.G. Atkins, J.F. Massicott, J.R. Armitage, R. Wyatt, B.J. Ainslie, and S.P. Craig-Ryan, "High-gain, broad spectral bandwidth erbium-doped fiber amplifier pumped near 1.5 µm," Electron. Lett. 25, 910-911 (1989).
[CrossRef]

1987 (2)

A.K. Ghatak, K. Thyagarajan, and M.R. Shenoy, "Numerical analysis of planar optical waveguides using matrix approach," IEEE J. Lightwave Technol. 5, 660-667 (1987).
[CrossRef]

C.A. Millar, M. C. Brierley, and S.R. Mallinson, "Exposed-core single-mode-fiber channel-dropping filter using a high-index overlay waveguide," Opt. Lett. 12, 284-286 (1987).
[CrossRef] [PubMed]

1985 (1)

1980 (1)

R.A. Bergh, G. Kotler, and H.J. Shaw, "Single-mode fiber optic directional coupler," Electron. Lett. 16, 260-261 (1980).
[CrossRef]

Ainslie, B.J.

C.G. Atkins, J.F. Massicott, J.R. Armitage, R. Wyatt, B.J. Ainslie, and S.P. Craig-Ryan, "High-gain, broad spectral bandwidth erbium-doped fiber amplifier pumped near 1.5 µm," Electron. Lett. 25, 910-911 (1989).
[CrossRef]

Ali, M. A.

J. Y. Pan, M. A. Ali, A. F. Elrefaie, and R. E. Wagner, "Multiwavelength fiber-amplifier cascades with equalization employing Mach-Zehnder optical filter," IEEE Photon. Technol. Lett. 7, 1501-1503 (1995).
[CrossRef]

Armitage, J.R.

C.G. Atkins, J.F. Massicott, J.R. Armitage, R. Wyatt, B.J. Ainslie, and S.P. Craig-Ryan, "High-gain, broad spectral bandwidth erbium-doped fiber amplifier pumped near 1.5 µm," Electron. Lett. 25, 910-911 (1989).
[CrossRef]

Ashwell, G.J.

R.B. Charters, A.P. Kuczyhski, S.E. Stakes, R.P. Tatam, and G.J. Ashwell, "In-line fiber optic channel dropping filter using Langmuir-Blodgett films," Electron. Lett. 30, 594-595 (1994).
[CrossRef]

Atkins, C.G.

C.G. Atkins, J.F. Massicott, J.R. Armitage, R. Wyatt, B.J. Ainslie, and S.P. Craig-Ryan, "High-gain, broad spectral bandwidth erbium-doped fiber amplifier pumped near 1.5 µm," Electron. Lett. 25, 910-911 (1989).
[CrossRef]

Bae, J.

J.K. Bae, J. Bae, S.H. Kim, N. Park, and S.B. Lee, "Dynamic EDFA gain-flattening filter using two LPFGs with divided coil heaters," IEEE Photon. Technol. Lett. 17, 1226-1228 (2005).
[CrossRef]

Bae, J.K.

J.K. Bae, J. Bae, S.H. Kim, N. Park, and S.B. Lee, "Dynamic EDFA gain-flattening filter using two LPFGs with divided coil heaters," IEEE Photon. Technol. Lett. 17, 1226-1228 (2005).
[CrossRef]

Baek, J.G.

I.B. Sohn, J.G. Baek, N.K. Lee, H.W. Kwon, and J.W. Song, "Gain flattened and improved EDFA using microbending long-period fiber gratings," Electron. Lett. 38, 1324-325 (2002).
[CrossRef]

Bennion, I.

Y. Liu, J.A.R. Williams, L. Zhang, and I. Bennion, "Phase shifted and cascaded long-period fiber gratings," Opt. Commun. 164, 27-31 (1999).
[CrossRef]

Bergh, R.A.

R.A. Bergh, G. Kotler, and H.J. Shaw, "Single-mode fiber optic directional coupler," Electron. Lett. 16, 260-261 (1980).
[CrossRef]

Bhatia, V.

A. M. Vengsarkar, P. J. Lemaire, J. B. Judkins, V. Bhatia, T. Erdogan, and J. E. Sipe, "Long-period fiber gratings as band-rejection filters," IEEE J. Lightwave Technol. 14, 58-64 (1996).
[CrossRef]

Brierley, M. C.

Charters, R.B.

R.B. Charters, A.P. Kuczyhski, S.E. Stakes, R.P. Tatam, and G.J. Ashwell, "In-line fiber optic channel dropping filter using Langmuir-Blodgett films," Electron. Lett. 30, 594-595 (1994).
[CrossRef]

Chen, H.F.

J.R. Qian and H.F. Chen, "Gain flattening fiber filters using phase shifted long period fiber gratings," Electron. Lett. 34, 1132-1133 (1998).
[CrossRef]

Chen, Z.H.

M.K. Pandit, K.S. Chiang, Z.H. Chen, and S.P. Li, "Tunable Long-Period Fiber Gratings for EDFA gain and ASE equalization," Microwave and Opt. Technol. Lett. 25, 181-184 (2000).
[CrossRef]

Chi, S.

J-C. Dung, S. Chi, and S. Wen, "Gain flattening of erbium-doped fiber amplifier using fiber Bragg gratings," Electron. Lett. 34, 555-556 (1998).
[CrossRef]

Chiang, K. S.

S. Li, K. S. Chiang, and W. A. Gambling, "Gain flattening of an erbium doped fiber amplifier using a high-birefringence fiber loop mirror," IEEE Photon. Technol. Lett. 13, 942-944 (2001).
[CrossRef]

Chiang, K.S.

M.K. Pandit, K.S. Chiang, Z.H. Chen, and S.P. Li, "Tunable Long-Period Fiber Gratings for EDFA gain and ASE equalization," Microwave and Opt. Technol. Lett. 25, 181-184 (2000).
[CrossRef]

Craig-Ryan, S.P.

C.G. Atkins, J.F. Massicott, J.R. Armitage, R. Wyatt, B.J. Ainslie, and S.P. Craig-Ryan, "High-gain, broad spectral bandwidth erbium-doped fiber amplifier pumped near 1.5 µm," Electron. Lett. 25, 910-911 (1989).
[CrossRef]

Digonnet, M.J.F.

Dung, J-C.

J-C. Dung, S. Chi, and S. Wen, "Gain flattening of erbium-doped fiber amplifier using fiber Bragg gratings," Electron. Lett. 34, 555-556 (1998).
[CrossRef]

Elrefaie, A. F.

J. Y. Pan, M. A. Ali, A. F. Elrefaie, and R. E. Wagner, "Multiwavelength fiber-amplifier cascades with equalization employing Mach-Zehnder optical filter," IEEE Photon. Technol. Lett. 7, 1501-1503 (1995).
[CrossRef]

Erdogan, T.

A. M. Vengsarkar, P. J. Lemaire, J. B. Judkins, V. Bhatia, T. Erdogan, and J. E. Sipe, "Long-period fiber gratings as band-rejection filters," IEEE J. Lightwave Technol. 14, 58-64 (1996).
[CrossRef]

Fawcett, G.

Feth, J.R.

Gambling, W. A.

S. Li, K. S. Chiang, and W. A. Gambling, "Gain flattening of an erbium doped fiber amplifier using a high-birefringence fiber loop mirror," IEEE Photon. Technol. Lett. 13, 942-944 (2001).
[CrossRef]

Ghatak, A.K.

A.K. Ghatak, K. Thyagarajan, and M.R. Shenoy, "Numerical analysis of planar optical waveguides using matrix approach," IEEE J. Lightwave Technol. 5, 660-667 (1987).
[CrossRef]

Giles, C.R.

C.R. Giles, "Lightwave applications of fiber Bragg gratings," IEEE J. Lightwave Technol. 15, 1391-1404 (1997).
[CrossRef]

Greene, P.D.

P.D. Greene and H.N. Rourke, "Tailoring long period optical fiber gratings for flattening EDFA gain spectra," Electron. Lett. 35, 1373-1374 (1999).
[CrossRef]

Harumoto, M.

M. Harumoto, M. Shigehara, and H. Suganuma, "Gain-flattening filter using long-period fiber gratings," IEEE J. Lightwave Technol. 20, 1027-1033 (2002).
[CrossRef]

Hu, A.Z.

Y.J. Rao, A.Z. Hu, and Y.C. Niu, "A novel dynamic LPFG gain equalizer written in a bend-insensitive fiber," Opt. Commun. 244, 137 -140 (2005).
[CrossRef]

Hwangbo, S.

K. T. Kim, S. Hwangbo, J. P. Mah, and K. R. Sohn, "Widely tunable filter based on coupling between a side-polished fiber and a tapered planar waveguide," IEEE Photon. Technol. Lett. 17, 142-144 (2005).
[CrossRef]

Iwashita, K.

S. Yoshida, S. Kuwano, and K. Iwashita, "Gain-flattened EDFA with high Al concentration for multistage repeatered WDM transmission systems," Electron. Lett. 31, 1765-1767 (1995).
[CrossRef]

Johnstone, W.

Judkins, J. B.

A. M. Vengsarkar, P. J. Lemaire, J. B. Judkins, V. Bhatia, T. Erdogan, and J. E. Sipe, "Long-period fiber gratings as band-rejection filters," IEEE J. Lightwave Technol. 14, 58-64 (1996).
[CrossRef]

Kanamori, T.

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

Kashyap, R.

R. Kashyap, R.  Wyatt, and P.F. McKee, "Wavelength flattened saturated erbium amplifier using multiple side-tap Bragg gratings," Electron. Lett. 29, 1025-1026 (1993).
[CrossRef]

Kim, B.Y.

H.S. Kim, S.H. Yun, H. K. Kim, N. Park, and B.Y. Kim, "Actively Gain-flattened erbium-doped fiber amplifier over 35 nm by using all-fiber acousto-optic tunable filters," IEEE Photon. Technol. Lett. 10, 790 -792 (1998).
[CrossRef]

Kim, H. K.

H.S. Kim, S.H. Yun, H. K. Kim, N. Park, and B.Y. Kim, "Actively Gain-flattened erbium-doped fiber amplifier over 35 nm by using all-fiber acousto-optic tunable filters," IEEE Photon. Technol. Lett. 10, 790 -792 (1998).
[CrossRef]

Kim, H.S.

H.S. Kim, S.H. Yun, H. K. Kim, N. Park, and B.Y. Kim, "Actively Gain-flattened erbium-doped fiber amplifier over 35 nm by using all-fiber acousto-optic tunable filters," IEEE Photon. Technol. Lett. 10, 790 -792 (1998).
[CrossRef]

Kim, K. T.

K. T. Kim, S. Hwangbo, J. P. Mah, and K. R. Sohn, "Widely tunable filter based on coupling between a side-polished fiber and a tapered planar waveguide," IEEE Photon. Technol. Lett. 17, 142-144 (2005).
[CrossRef]

Kim, S.H.

J.K. Bae, J. Bae, S.H. Kim, N. Park, and S.B. Lee, "Dynamic EDFA gain-flattening filter using two LPFGs with divided coil heaters," IEEE Photon. Technol. Lett. 17, 1226-1228 (2005).
[CrossRef]

Kobayashi, K.

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

Kompella, J.

A. Sharma, J. Kompella, and P.K. Mishra, "Analysis of fiber directional couplers and coupler half-blocks using a new simple model for single-mode fibers,"IEEE J. Lightwave Technol. 8, 143-151 (1990).
[CrossRef]

Kotler, G.

R.A. Bergh, G. Kotler, and H.J. Shaw, "Single-mode fiber optic directional coupler," Electron. Lett. 16, 260-261 (1980).
[CrossRef]

Kuczyhski, A.P.

R.B. Charters, A.P. Kuczyhski, S.E. Stakes, R.P. Tatam, and G.J. Ashwell, "In-line fiber optic channel dropping filter using Langmuir-Blodgett films," Electron. Lett. 30, 594-595 (1994).
[CrossRef]

Kumar, N.

N. Kumar, M.R. Shenoy, and B.P. Pal, "A standard fiber-based loop mirror as a gain-flattening filter for erbium-doped fiber amplifiers," IEEE Photon. Technol. Lett. 17, 2056-2058 (2005).
[CrossRef]

Kuwano, S.

S. Yoshida, S. Kuwano, and K. Iwashita, "Gain-flattened EDFA with high Al concentration for multistage repeatered WDM transmission systems," Electron. Lett. 31, 1765-1767 (1995).
[CrossRef]

Kwon, H.W.

I.B. Sohn, J.G. Baek, N.K. Lee, H.W. Kwon, and J.W. Song, "Gain flattened and improved EDFA using microbending long-period fiber gratings," Electron. Lett. 38, 1324-325 (2002).
[CrossRef]

Lee, N.K.

I.B. Sohn, J.G. Baek, N.K. Lee, H.W. Kwon, and J.W. Song, "Gain flattened and improved EDFA using microbending long-period fiber gratings," Electron. Lett. 38, 1324-325 (2002).
[CrossRef]

Lee, S.B.

J.K. Bae, J. Bae, S.H. Kim, N. Park, and S.B. Lee, "Dynamic EDFA gain-flattening filter using two LPFGs with divided coil heaters," IEEE Photon. Technol. Lett. 17, 1226-1228 (2005).
[CrossRef]

Lemaire, P. J.

A. M. Vengsarkar, P. J. Lemaire, J. B. Judkins, V. Bhatia, T. Erdogan, and J. E. Sipe, "Long-period fiber gratings as band-rejection filters," IEEE J. Lightwave Technol. 14, 58-64 (1996).
[CrossRef]

Li, S.

S. Li, K. S. Chiang, and W. A. Gambling, "Gain flattening of an erbium doped fiber amplifier using a high-birefringence fiber loop mirror," IEEE Photon. Technol. Lett. 13, 942-944 (2001).
[CrossRef]

Li, S.P.

M.K. Pandit, K.S. Chiang, Z.H. Chen, and S.P. Li, "Tunable Long-Period Fiber Gratings for EDFA gain and ASE equalization," Microwave and Opt. Technol. Lett. 25, 181-184 (2000).
[CrossRef]

Liu, Y.

Y. Liu, J.A.R. Williams, L. Zhang, and I. Bennion, "Phase shifted and cascaded long-period fiber gratings," Opt. Commun. 164, 27-31 (1999).
[CrossRef]

Mah, J. P.

K. T. Kim, S. Hwangbo, J. P. Mah, and K. R. Sohn, "Widely tunable filter based on coupling between a side-polished fiber and a tapered planar waveguide," IEEE Photon. Technol. Lett. 17, 142-144 (2005).
[CrossRef]

Mallinson, S.R.

Massicott, J.F.

C.G. Atkins, J.F. Massicott, J.R. Armitage, R. Wyatt, B.J. Ainslie, and S.P. Craig-Ryan, "High-gain, broad spectral bandwidth erbium-doped fiber amplifier pumped near 1.5 µm," Electron. Lett. 25, 910-911 (1989).
[CrossRef]

McCallion, K.

McKee, P.F.

R. Kashyap, R.  Wyatt, and P.F. McKee, "Wavelength flattened saturated erbium amplifier using multiple side-tap Bragg gratings," Electron. Lett. 29, 1025-1026 (1993).
[CrossRef]

Millar, C.A.

Mishra, P.K.

A. Sharma, J. Kompella, and P.K. Mishra, "Analysis of fiber directional couplers and coupler half-blocks using a new simple model for single-mode fibers,"IEEE J. Lightwave Technol. 8, 143-151 (1990).
[CrossRef]

Moodie, D.G.

Mori, A.

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

Nishida, Y.

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

Niu, Y.C.

Y.J. Rao, A.Z. Hu, and Y.C. Niu, "A novel dynamic LPFG gain equalizer written in a bend-insensitive fiber," Opt. Commun. 244, 137 -140 (2005).
[CrossRef]

Ohishi, Y.

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

Oikawa, K.

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

Ono, H.

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

Pal, B.P.

R.K. Varshney, A. Singh, K. Pande, and B.P. Pal, "Side-polished fiber-based gain-flattening filter for erbium doped fiber amplifiers," Opt. Commun. 271, 441- 444 (2007).
[CrossRef]

N. Kumar, M.R. Shenoy, and B.P. Pal, "A standard fiber-based loop mirror as a gain-flattening filter for erbium-doped fiber amplifiers," IEEE Photon. Technol. Lett. 17, 2056-2058 (2005).
[CrossRef]

B.P. Pal, G. Raizada, and R.K. Varshney, "Modelling a Fiber Half-block with Multimode Overlay Waveguide," J. Opt. Commun. 17, 179-83 (1996).

G. Raizada, B.P. Pal, and R.K. Varshney, "Estimating performance of fiber optic modulators/switches with multimode electro-optic overlay/interlay waveguide," Opt. Fib. Tech. 2, 89-97 (1996).
[CrossRef]

Pan, J. Y.

J. Y. Pan, M. A. Ali, A. F. Elrefaie, and R. E. Wagner, "Multiwavelength fiber-amplifier cascades with equalization employing Mach-Zehnder optical filter," IEEE Photon. Technol. Lett. 7, 1501-1503 (1995).
[CrossRef]

Pande, K.

R.K. Varshney, A. Singh, K. Pande, and B.P. Pal, "Side-polished fiber-based gain-flattening filter for erbium doped fiber amplifiers," Opt. Commun. 271, 441- 444 (2007).
[CrossRef]

Pandit, M.K.

M.K. Pandit, K.S. Chiang, Z.H. Chen, and S.P. Li, "Tunable Long-Period Fiber Gratings for EDFA gain and ASE equalization," Microwave and Opt. Technol. Lett. 25, 181-184 (2000).
[CrossRef]

Park, N.

J.K. Bae, J. Bae, S.H. Kim, N. Park, and S.B. Lee, "Dynamic EDFA gain-flattening filter using two LPFGs with divided coil heaters," IEEE Photon. Technol. Lett. 17, 1226-1228 (2005).
[CrossRef]

H.S. Kim, S.H. Yun, H. K. Kim, N. Park, and B.Y. Kim, "Actively Gain-flattened erbium-doped fiber amplifier over 35 nm by using all-fiber acousto-optic tunable filters," IEEE Photon. Technol. Lett. 10, 790 -792 (1998).
[CrossRef]

Pechstedt, R. D.

R. D. Pechstedt and P. St. J. Russell, "Narrow-band in-line fiber filter using surface-guided Bloch modes supported by dielectric multilayer stacks," IEEE J. Lightwave Technol. 14, 1541-1545 (1996).
[CrossRef]

Qian, J.R.

J.R. Qian and H.F. Chen, "Gain flattening fiber filters using phase shifted long period fiber gratings," Electron. Lett. 34, 1132-1133 (1998).
[CrossRef]

Raizada, G.

G. Raizada, B.P. Pal, and R.K. Varshney, "Estimating performance of fiber optic modulators/switches with multimode electro-optic overlay/interlay waveguide," Opt. Fib. Tech. 2, 89-97 (1996).
[CrossRef]

B.P. Pal, G. Raizada, and R.K. Varshney, "Modelling a Fiber Half-block with Multimode Overlay Waveguide," J. Opt. Commun. 17, 179-83 (1996).

Rao, Y.J.

Y.J. Rao, A.Z. Hu, and Y.C. Niu, "A novel dynamic LPFG gain equalizer written in a bend-insensitive fiber," Opt. Commun. 244, 137 -140 (2005).
[CrossRef]

Rourke, H.N.

P.D. Greene and H.N. Rourke, "Tailoring long period optical fiber gratings for flattening EDFA gain spectra," Electron. Lett. 35, 1373-1374 (1999).
[CrossRef]

Russell, P. St. J.

R. D. Pechstedt and P. St. J. Russell, "Narrow-band in-line fiber filter using surface-guided Bloch modes supported by dielectric multilayer stacks," IEEE J. Lightwave Technol. 14, 1541-1545 (1996).
[CrossRef]

Sharma, A.

A. Sharma, J. Kompella, and P.K. Mishra, "Analysis of fiber directional couplers and coupler half-blocks using a new simple model for single-mode fibers,"IEEE J. Lightwave Technol. 8, 143-151 (1990).
[CrossRef]

Shaw, H.J.

Shenoy, M.R.

N. Kumar, M.R. Shenoy, and B.P. Pal, "A standard fiber-based loop mirror as a gain-flattening filter for erbium-doped fiber amplifiers," IEEE Photon. Technol. Lett. 17, 2056-2058 (2005).
[CrossRef]

A.K. Ghatak, K. Thyagarajan, and M.R. Shenoy, "Numerical analysis of planar optical waveguides using matrix approach," IEEE J. Lightwave Technol. 5, 660-667 (1987).
[CrossRef]

Shigehara, M.

M. Harumoto, M. Shigehara, and H. Suganuma, "Gain-flattening filter using long-period fiber gratings," IEEE J. Lightwave Technol. 20, 1027-1033 (2002).
[CrossRef]

Singh, A.

R.K. Varshney, A. Singh, K. Pande, and B.P. Pal, "Side-polished fiber-based gain-flattening filter for erbium doped fiber amplifiers," Opt. Commun. 271, 441- 444 (2007).
[CrossRef]

Sipe, J. E.

A. M. Vengsarkar, P. J. Lemaire, J. B. Judkins, V. Bhatia, T. Erdogan, and J. E. Sipe, "Long-period fiber gratings as band-rejection filters," IEEE J. Lightwave Technol. 14, 58-64 (1996).
[CrossRef]

Sohn, I.B.

I.B. Sohn, J.G. Baek, N.K. Lee, H.W. Kwon, and J.W. Song, "Gain flattened and improved EDFA using microbending long-period fiber gratings," Electron. Lett. 38, 1324-325 (2002).
[CrossRef]

Sohn, K. R.

K. T. Kim, S. Hwangbo, J. P. Mah, and K. R. Sohn, "Widely tunable filter based on coupling between a side-polished fiber and a tapered planar waveguide," IEEE Photon. Technol. Lett. 17, 142-144 (2005).
[CrossRef]

Song, J.W.

I.B. Sohn, J.G. Baek, N.K. Lee, H.W. Kwon, and J.W. Song, "Gain flattened and improved EDFA using microbending long-period fiber gratings," Electron. Lett. 38, 1324-325 (2002).
[CrossRef]

Stakes, S.E.

R.B. Charters, A.P. Kuczyhski, S.E. Stakes, R.P. Tatam, and G.J. Ashwell, "In-line fiber optic channel dropping filter using Langmuir-Blodgett films," Electron. Lett. 30, 594-595 (1994).
[CrossRef]

Stokes, L.F.

Suganuma, H.

M. Harumoto, M. Shigehara, and H. Suganuma, "Gain-flattening filter using long-period fiber gratings," IEEE J. Lightwave Technol. 20, 1027-1033 (2002).
[CrossRef]

Tatam, R.P.

R.B. Charters, A.P. Kuczyhski, S.E. Stakes, R.P. Tatam, and G.J. Ashwell, "In-line fiber optic channel dropping filter using Langmuir-Blodgett films," Electron. Lett. 30, 594-595 (1994).
[CrossRef]

Thyagarajan, K.

A.K. Ghatak, K. Thyagarajan, and M.R. Shenoy, "Numerical analysis of planar optical waveguides using matrix approach," IEEE J. Lightwave Technol. 5, 660-667 (1987).
[CrossRef]

Varshney, R.K.

R.K. Varshney, A. Singh, K. Pande, and B.P. Pal, "Side-polished fiber-based gain-flattening filter for erbium doped fiber amplifiers," Opt. Commun. 271, 441- 444 (2007).
[CrossRef]

B.P. Pal, G. Raizada, and R.K. Varshney, "Modelling a Fiber Half-block with Multimode Overlay Waveguide," J. Opt. Commun. 17, 179-83 (1996).

G. Raizada, B.P. Pal, and R.K. Varshney, "Estimating performance of fiber optic modulators/switches with multimode electro-optic overlay/interlay waveguide," Opt. Fib. Tech. 2, 89-97 (1996).
[CrossRef]

Vengsarkar, A. M.

A. M. Vengsarkar, P. J. Lemaire, J. B. Judkins, V. Bhatia, T. Erdogan, and J. E. Sipe, "Long-period fiber gratings as band-rejection filters," IEEE J. Lightwave Technol. 14, 58-64 (1996).
[CrossRef]

Wagner, R. E.

J. Y. Pan, M. A. Ali, A. F. Elrefaie, and R. E. Wagner, "Multiwavelength fiber-amplifier cascades with equalization employing Mach-Zehnder optical filter," IEEE Photon. Technol. Lett. 7, 1501-1503 (1995).
[CrossRef]

Wen, S.

J-C. Dung, S. Chi, and S. Wen, "Gain flattening of erbium-doped fiber amplifier using fiber Bragg gratings," Electron. Lett. 34, 555-556 (1998).
[CrossRef]

Williams, J.A.R.

Y. Liu, J.A.R. Williams, L. Zhang, and I. Bennion, "Phase shifted and cascaded long-period fiber gratings," Opt. Commun. 164, 27-31 (1999).
[CrossRef]

Wyatt, R.

R. Kashyap, R.  Wyatt, and P.F. McKee, "Wavelength flattened saturated erbium amplifier using multiple side-tap Bragg gratings," Electron. Lett. 29, 1025-1026 (1993).
[CrossRef]

C.G. Atkins, J.F. Massicott, J.R. Armitage, R. Wyatt, B.J. Ainslie, and S.P. Craig-Ryan, "High-gain, broad spectral bandwidth erbium-doped fiber amplifier pumped near 1.5 µm," Electron. Lett. 25, 910-911 (1989).
[CrossRef]

Yamada, M.

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

Yoshida, S.

S. Yoshida, S. Kuwano, and K. Iwashita, "Gain-flattened EDFA with high Al concentration for multistage repeatered WDM transmission systems," Electron. Lett. 31, 1765-1767 (1995).
[CrossRef]

Yun, S.H.

H.S. Kim, S.H. Yun, H. K. Kim, N. Park, and B.Y. Kim, "Actively Gain-flattened erbium-doped fiber amplifier over 35 nm by using all-fiber acousto-optic tunable filters," IEEE Photon. Technol. Lett. 10, 790 -792 (1998).
[CrossRef]

Zhang, L.

Y. Liu, J.A.R. Williams, L. Zhang, and I. Bennion, "Phase shifted and cascaded long-period fiber gratings," Opt. Commun. 164, 27-31 (1999).
[CrossRef]

Electron. Lett. (9)

C.G. Atkins, J.F. Massicott, J.R. Armitage, R. Wyatt, B.J. Ainslie, and S.P. Craig-Ryan, "High-gain, broad spectral bandwidth erbium-doped fiber amplifier pumped near 1.5 µm," Electron. Lett. 25, 910-911 (1989).
[CrossRef]

S. Yoshida, S. Kuwano, and K. Iwashita, "Gain-flattened EDFA with high Al concentration for multistage repeatered WDM transmission systems," Electron. Lett. 31, 1765-1767 (1995).
[CrossRef]

R. Kashyap, R.  Wyatt, and P.F. McKee, "Wavelength flattened saturated erbium amplifier using multiple side-tap Bragg gratings," Electron. Lett. 29, 1025-1026 (1993).
[CrossRef]

J-C. Dung, S. Chi, and S. Wen, "Gain flattening of erbium-doped fiber amplifier using fiber Bragg gratings," Electron. Lett. 34, 555-556 (1998).
[CrossRef]

J.R. Qian and H.F. Chen, "Gain flattening fiber filters using phase shifted long period fiber gratings," Electron. Lett. 34, 1132-1133 (1998).
[CrossRef]

P.D. Greene and H.N. Rourke, "Tailoring long period optical fiber gratings for flattening EDFA gain spectra," Electron. Lett. 35, 1373-1374 (1999).
[CrossRef]

I.B. Sohn, J.G. Baek, N.K. Lee, H.W. Kwon, and J.W. Song, "Gain flattened and improved EDFA using microbending long-period fiber gratings," Electron. Lett. 38, 1324-325 (2002).
[CrossRef]

R.A. Bergh, G. Kotler, and H.J. Shaw, "Single-mode fiber optic directional coupler," Electron. Lett. 16, 260-261 (1980).
[CrossRef]

R.B. Charters, A.P. Kuczyhski, S.E. Stakes, R.P. Tatam, and G.J. Ashwell, "In-line fiber optic channel dropping filter using Langmuir-Blodgett films," Electron. Lett. 30, 594-595 (1994).
[CrossRef]

IEEE J. Lightwave Technol. (6)

R. D. Pechstedt and P. St. J. Russell, "Narrow-band in-line fiber filter using surface-guided Bloch modes supported by dielectric multilayer stacks," IEEE J. Lightwave Technol. 14, 1541-1545 (1996).
[CrossRef]

A. Sharma, J. Kompella, and P.K. Mishra, "Analysis of fiber directional couplers and coupler half-blocks using a new simple model for single-mode fibers,"IEEE J. Lightwave Technol. 8, 143-151 (1990).
[CrossRef]

A.K. Ghatak, K. Thyagarajan, and M.R. Shenoy, "Numerical analysis of planar optical waveguides using matrix approach," IEEE J. Lightwave Technol. 5, 660-667 (1987).
[CrossRef]

M. Harumoto, M. Shigehara, and H. Suganuma, "Gain-flattening filter using long-period fiber gratings," IEEE J. Lightwave Technol. 20, 1027-1033 (2002).
[CrossRef]

A. M. Vengsarkar, P. J. Lemaire, J. B. Judkins, V. Bhatia, T. Erdogan, and J. E. Sipe, "Long-period fiber gratings as band-rejection filters," IEEE J. Lightwave Technol. 14, 58-64 (1996).
[CrossRef]

C.R. Giles, "Lightwave applications of fiber Bragg gratings," IEEE J. Lightwave Technol. 15, 1391-1404 (1997).
[CrossRef]

IEEE Photon. Technol. Lett. (7)

S. Li, K. S. Chiang, and W. A. Gambling, "Gain flattening of an erbium doped fiber amplifier using a high-birefringence fiber loop mirror," IEEE Photon. Technol. Lett. 13, 942-944 (2001).
[CrossRef]

N. Kumar, M.R. Shenoy, and B.P. Pal, "A standard fiber-based loop mirror as a gain-flattening filter for erbium-doped fiber amplifiers," IEEE Photon. Technol. Lett. 17, 2056-2058 (2005).
[CrossRef]

M. Yamada, A. Mori, K. Kobayashi, H. Ono, T. Kanamori, K. Oikawa, Y. Nishida, and Y. Ohishi, "Gain-Flattened Tellurite-Based EDFA with a Flat Amplification Bandwidth of 76 nm," IEEE Photon. Technol. Lett. 10, 1244-1246 (1998).
[CrossRef]

J. Y. Pan, M. A. Ali, A. F. Elrefaie, and R. E. Wagner, "Multiwavelength fiber-amplifier cascades with equalization employing Mach-Zehnder optical filter," IEEE Photon. Technol. Lett. 7, 1501-1503 (1995).
[CrossRef]

H.S. Kim, S.H. Yun, H. K. Kim, N. Park, and B.Y. Kim, "Actively Gain-flattened erbium-doped fiber amplifier over 35 nm by using all-fiber acousto-optic tunable filters," IEEE Photon. Technol. Lett. 10, 790 -792 (1998).
[CrossRef]

J.K. Bae, J. Bae, S.H. Kim, N. Park, and S.B. Lee, "Dynamic EDFA gain-flattening filter using two LPFGs with divided coil heaters," IEEE Photon. Technol. Lett. 17, 1226-1228 (2005).
[CrossRef]

K. T. Kim, S. Hwangbo, J. P. Mah, and K. R. Sohn, "Widely tunable filter based on coupling between a side-polished fiber and a tapered planar waveguide," IEEE Photon. Technol. Lett. 17, 142-144 (2005).
[CrossRef]

J. Opt. Commun. (1)

B.P. Pal, G. Raizada, and R.K. Varshney, "Modelling a Fiber Half-block with Multimode Overlay Waveguide," J. Opt. Commun. 17, 179-83 (1996).

Microwave and Opt. Technol. Lett. (1)

M.K. Pandit, K.S. Chiang, Z.H. Chen, and S.P. Li, "Tunable Long-Period Fiber Gratings for EDFA gain and ASE equalization," Microwave and Opt. Technol. Lett. 25, 181-184 (2000).
[CrossRef]

Opt. Commun. (3)

Y.J. Rao, A.Z. Hu, and Y.C. Niu, "A novel dynamic LPFG gain equalizer written in a bend-insensitive fiber," Opt. Commun. 244, 137 -140 (2005).
[CrossRef]

R.K. Varshney, A. Singh, K. Pande, and B.P. Pal, "Side-polished fiber-based gain-flattening filter for erbium doped fiber amplifiers," Opt. Commun. 271, 441- 444 (2007).
[CrossRef]

Y. Liu, J.A.R. Williams, L. Zhang, and I. Bennion, "Phase shifted and cascaded long-period fiber gratings," Opt. Commun. 164, 27-31 (1999).
[CrossRef]

Opt. Fib. Tech. (1)

G. Raizada, B.P. Pal, and R.K. Varshney, "Estimating performance of fiber optic modulators/switches with multimode electro-optic overlay/interlay waveguide," Opt. Fib. Tech. 2, 89-97 (1996).
[CrossRef]

Opt. Lett. (4)

Other (10)

R.K. Varshney, "Side-polished fiber coupler half block and devices," in Guided Wave Optics, A. Sharma, ed. (Viva Books Pvt. Ltd., New Delhi, India, 2005), pp. 110-121.

W. Johnstone, "Side polished evanescently coupled optical fiber overlay devices: a review," in Guided wave optical components and devices: basics, technology and applications, B.P. Pal., ed. (Academic Press, Elsevier, Burlington, 2006), pp. 225-232.

B.P. Pal, "All-fiber guided wave components," in Electromagnetic fields in unconventional structures and materials, A. Lakhtakia and O.N. Singh, eds. (John Wiley, New York, 2000), pp. 359-432.

A. Srivastava and Y. Sun, Chapter 12 "Erbium doped fiber amplifiers for dynamic optical networks," in Guided wave optical components and devices: basics, technology and applications, B.P. Pal., ed. (Academic Press, Elsevier, Burlington, 2006), pp. 181-203

W.V. Sorin, "Broadband tunable in-line filter for fiber optics," US Patent no. 4.986,623 (1991).

S. Zhao and B. Pi, "Mach-Zehnder interferometers and applications based on evanescent couplings through side-polished fiber coupling ports," US Patent no. 6,501,875 B2, (2002).

M. Lelic, G.J. Cowley, and N. Menon, "Dynamic controller for a multichannel optical amplifier," US Patent No. 6,535,330 (2003).

B.Y. Kim, S.H. Yun, and B.W. Lee, "Acousto-optic filter", US Patent No. 6,532,323 B2 (2003).

A. Mori, Y. Ohishi, M. Yamada, H. Ono, Y. Nishida, K. Oikawa, and S. Sudo, "1.5 ?m broadband amplification by tellurite-based EDFA’s," in Optical Fiber Communication conference, Technical Digest (Optical Society of America, 1997), post-deadline paper PD1.

M. Yamada, H. Ono, A. Mori, T. Kanamori, S. Sudo, and Y. Ohishi, "Ultra-broadband and gain-flattened EDFA’s for WDM signals," in Optical Amplifiers and Their Applications, Technical Digest (Optical Society of America, 1997), paper MB1.

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Figures (8)

Fig. 1.
Fig. 1.

Schematic diagram of (a) SPF loaded with tapered MMOW (b) position of SPF half block relative to tapered MMOW.

Fig. 2.
Fig. 2.

Diagram illustrating the staircase approximation (for taking into account curvature of the fiber and tapered nature of overlay waveguide) used to model the GEF device (see text).

Fig. 3.
Fig. 3.

Three sample results to demonstrate tunability of transfer function of the device through controlled translation of SPF half-coupler block relative to the tapered MMOW; (a) tuning of the notch position (b) tuning of the notch depth.

Fig. 4.
Fig. 4.

Measured signal output spectra for 8 amplified DWDM signal channels from the EDFA in an OSA (a) without and (b) with the GEF integrated with the EDFA; signal power was -20 dBm and pump power was 140 mW.

Fig. 5.
Fig. 5.

(a) Equalized signal output spectra from the EDFA in the presence of eight DWDM signal channels when signal power was changed from -20 dBm to -15 dBm; pump power was kept fixed at 140 mW; (b) Corresponding results when the pump power was reduced from 140 mW to 85 mW; input signal power level was kept at -20 dBm.

Fig. 6.
Fig. 6.

Equalized signal output spectra from the EDFA; for case (a) 6 DWDM channels were dropped and for case (b) two channels were added.

Fig. 7.
Fig. 7.

Variation of peak signal power with respect to the average gain for all the gain flattening results shown above (average power level is set to zero for each case).

Fig. 8.
Fig. 8.

(a) Various curves showing the variations in throughput power spectra for ±2% variations in the parameter S 0 from its optimum value; (b) Corresponding curves for ±10% variations in the parameter R c.

Equations (1)

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S i S 0 + L eff 2 i × d z 2 2 R c

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