Integrated Optics - Applied Optics Fundamentals and Device Applications - page 224

at 0.86 μm can be built with better than 20 dB gain [7]; therefore in terms
of system loss, the addition of this one additional component on the chip
is advantageous. Furthermore, since the structure required for the optical
amplifier is identical to the laser diode structure, the fabrication complexity
will not be significantly increased.
Numerous current and downstream applications for 0.86 μm integrated
optics technology provide substantial justification for its continued develop-
ment. A powerful motivation for working in the 0.86 μm region is the blos-
soming area of nonlinear optics, or exitonic absorption phenomena, which
are expected to permit the realization of modulation and switching speeds
on the order of 100 fs (10 −13 s). Optical systems with this capability will find
application in optical signal processing for digital computation and for total
information wide-band processing as required in the multi-information

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16

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13

Kuznetsov

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11

Marcatili

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7

λ 0 = 1.3 µm
a = b = 5.0 µm
N D = 11×10 17 cm -3
α ~ 0.57 dB cm -1

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5

4

Parallel channel
directional coupler
L versus C

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2

1

0

1 2 3 4 5 6 7 8 9 10 11 12 13 14

(a) C (µm)

FIGURE 5.14
(a) λ 0 = 1.3 μm; a = b = 5.0 μm; N D = 11 × 10 17 cm −3 parallel direction channel directional coupler L
versus C .